# data[].attributes.headline
California's Environmental Principles and Concepts (EP&Cs)

# data[].attributes.subject
California's Environmental Principles and Concepts (EP&Cs)

# data[].attributes.attachment_link.readable_text
California's Environmental Principles and Concepts (EP&Cs) highlight the deep relationship between humans and the natural world.

Students and teachers need not memorize the five environmental principles and fifteen supporting concepts. Rather, they are "big ideas" intended to inform standards-based instruction and fuel student inquiry. Teachers can support environmental literacy by helping students to understand and apply the EP&Cs across academic disciplines and in the real world.

By law, the EP&Cs must be addressed in future California textbooks and instructional materials adopted by the state. In 2016, the EP&Cs were integrated into the revised California History-Social Science and the new California Science framework. As a result, subsequent state textbook adoptions will incorporate the EP&Cs.

Principle 1 - People Depend on Natural Systems

The continuation and health of individual human lives and of human communities and societies depend on the health of the natural systems that provide essential goods and ecosystem services.

Concept A. The goods produced by natural systems are essential to human life and to the functioning of our economies and cultures.
Concept B. The ecosystem services provided by natural systems are essential to human life and to the functioning of our economies and cultures.
Concept C. That the quality, quantity, and reliability of the goods and ecosystem services provided by natural systems are directly affected by the health of those systems.

Principle 2 - People Influence Natural Systems

The long-term functioning and health of terrestrial, freshwater, coastal, and marine ecosystems are influenced by their relationships with human societies.

Concept A. Direct and indirect changes to natural systems due to the growth of human populations and their consumption rates influence the geographic extent, composition, biological diversity, and viability of natural systems.
Concept B. Methods used to extract, harvest, transport, and consume natural resources influence the geographic extent, composition, biological diversity, and viability of natural systems.
Concept C. The expansion and operation of human communities influences the geographic extent, composition, biological diversity, and viability of natural systems.
Concept D. The legal, economic, and political systems that govern the use and management of natural systems directly influence the geographic extent, composition, biological diversity, and viability of natural systems.

Principle 3 - Natural Systems Change in Ways that People Benefit From and Can Influence

Natural systems proceed through cycles that humans depend upon, benefit from, and can alter.

Concept A. Natural systems proceed through cycles and processes that are required for their functioning.
Concept B. Human practices depend upon and benefit from the cycles and processes that operate within natural systems.
Concept C. Human practices can alter the cycles and processes that operate within natural systems.

Principle 4 - There are no Permanent or Impermeable Boundaries that Prevent Matter from Flowing Between Systems

The exchange of matter between natural systems and human societies affects the long-term functioning of both.

Concept A. The effects of human activities on natural systems are directly related to the quantities of resources consumed and to the quantity and characteristics of the resulting byproducts.
Concept B. The byproducts of human activity are not readily prevented from entering natural systems and may be beneficial, neutral, or detrimental in their effect.
Concept C. The capacity of natural systems to adjust to human-caused alterations depends on the nature of the system as well as the scope, scale, and duration of the activity and the nature of its byproducts.

Principle 5 - Decisions Affecting Resources and Natural Systems are Complex and Involve Many Factors

Decisions affecting resources and natural systems are based on a wide range of considerations and decision-making processes.

Concept A. There is a spectrum of what is considered in making decisions about resources and natural systems and how those factors influence decisions.
Concept B. The process of making decisions about resources and natural systems, and how the assessment of social, economic, political, and environmental factors has changed over time.

# data[].attributes.attachment_link.title
Environmental Principles & Concepts - California Education and the Environment Initiative (EEI)

# data[].attributes.attachment_link.description
California's Environmental Principles and Concepts (EP&Cs) highlight the deep relationship between humans and the natural world. Students and teachers need not memorize the five environmental principles and fifteen supporting concepts. Rather, they are "big ideas" intended to inform standards-based instruction and fuel student inquiry.

# data[].attributes.attachment_link.description
The Keeling Curve is a daily record of global atmospheric carbon dioxide concentration maintained by Scripps Institution of Oceanography at UC San Diego.

# data[].attributes.body
Lots of scientific details on oysters and an observed die-off in Oregon due to low pH/low saturation state waters.

# data[].attributes.headline
What's Really Warming the World? (Bloomberg)

# data[].attributes.subject
What's Really Warming the World? (Bloomberg)

# data[].attributes.attachment_link.description
What’s Really Warming the World? Climate deniers blame natural factors; NASA data proves otherwise

# data[].attributes.headline
NPR: When did Humans Start Shaping Earth's Fate? An Epoch Debate

# data[].attributes.subject
NPR: When did Humans Start Shaping Earth's Fate? An Epoch Debate

# data[].attributes.attachment_link.readable_text
Humans have had such a huge impact on the Earth that some geologists think the human era should be enshrined in the official timeline of our planet.

They want to give the age of humans a formal name, just as scientists use terms like the Jurassic or the Cretaceous to talk about the age of dinosaurs.

But some researchers think that formally establishing an "Anthropocene" - as many call it - as part of the geologic time scale would be a big mistake.

The debate is heating up as a working group is getting closer to making recommendations to the scientific organization that decides such things - the International Union of Geological Sciences. The working group's interim report is expected by next year.

"The Anthropocene does, the more you look at it, become more geologically real," says Jan Zalasiewicz of the University of Leicester in the United Kingdom, who's a member of the group. "We seem to be moving towards saying that the Anthropocene should be formalized."

"If the Anthropocene began in 1945, then the entire story of changing the surface of the Earth by cutting forests and plowing prairies occurred before the Anthropocene. Does that make sense?"

The Earth is about 4.5 billion years old. Scientists have divided up that vast stretch of time into categories and subcategories. There are eons and eras and periods and epochs, says Zalasiewicz. "Currently, formally, we live in something called the Holocene epoch."

He says the push to give an official name to the time of human domination began about 15 years ago. A prominent atmospheric chemist named Paul Crutzen spontaneously came up with the term at a meeting where people were talking about environmental change in the Holocene, and he later learned that biologist Eugene Stoermer had been using it as well.

As an informal term, it's really caught on, and all kinds of scientists are now using it. The question is whether or not to make it official. And that question is a lot trickier than it might seem. For example, scientists would first have to define when this new age began.

One early idea was that it began with the Industrial Revolution, says Zalasiewicz, "but the majority of us are beginning to favor a more recent time, in the mid-20th century."

That's because this is when human activities first left clear marks in the geologic record. Geologists like to see those kinds of unmistakable signals in the rock to mark the beginning of an official time period.

Earlier this year, scientists proposed pegging the start date of the Anthropocene at July 16, 1945 - the day of the first nuclear bomb explosion. Atom bomb tests produced fallout that can be detected in ice cores, soils and sediments all over the planet.

And about the same time, the world started to be sprinkled with a byproduct of fossil fuel combustion called spheroidal carbonaceous fly ash particles.

"They would be a good marker for the Anthropocene if it is decided that it started in the mid-20th century," Neil Rose of University College London told NPR by email. He's just published a report showing a dramatic increase in accumulations of these particles starting around 1950.

But some researchers say, wait a second - humans actually began to transform the planet thousands of years earlier, with the development of agriculture.

"If the Anthropocene began in 1945, then the entire story of changing the surface of the earth by cutting forests and plowing prairies occurred before the Anthropocene," points out Bill Ruddiman, a climate scientist at the University of Virginia. "Does that make sense?"

In the current issue of the journal Science, he and some colleagues argue that the Anthroprocene is a useful concept but that trying to formally define it isn't helpful.

"I think this formal definition would be a mistake," says Ruddiman. He compares it to a group of historians trying to say that the settlement of the American West started with the completion of the Sears Tower in Chicago in the early 1970s. "That just leaves out an enormous, rich, interesting history, if you did something like that."

Plus, the geologic time periods in use today were originally developed as scientists tried to piece together Earth's unknown history by looking at rocks and fossils - because rocks and fossils were all they had. Humanity's impact on the Earth can be traced in a totally different way, points out Stan Finney, a geologist at California State University, Long Beach.

"We have human observations. We have human written records. We have human measurements from instruments," says Finney. "Why do we have to go find something in the rock record?"

What's more, he asks, "Does it really need to be formally defined? We have many terms for major events in Earth's history that are not part of the geologic timescale."

When the first plants evolved to grow on land, there were dramatic changes to the Earth's surface and atmosphere. "We don't have a name for that incredible revolution and period in Earth's history," Finney says. "We refer to it, the time during which it occurred, as from the late Devonian through the Pennsylvanian."

He says proponents of a formal term seem motivated by the desire to make a political statement. One editorial in Nature in 2011 argued that formally defining the Anthropocene "would encourage a mindset that will be important not only to fully understand the transformation now occurring, but to take action to control it."

But the various bodies under the International Union of Geological Sciences that would have to consider the creation of a new term normally devote themselves to pondering highly technical issues in geology, rather than political questions.

"It's quite a long road ahead," says Zalasiewicz, who expects that nothing will be settled for at least a few years.

# data[].attributes.attachment_link.title
When Did Humans Start Shaping Earth's Fate? An Epoch Debate

# data[].attributes.attachment_link.description
Humans have had such a huge impact on the Earth that some geologists think the human era should be enshrined in the official timeline of our planet. They want to give the age of humans a formal name, just as scientists use terms like the Jurassic or the Cretaceous to talk about the age of dinosaurs.

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.readable_text
The amount of anthropogenic carbon dioxide (CO ₂) absorbed by Earth's life forms, ocean, and other "sinks" might decrease as time goes by. Natural carbon sinks (the carbon absorbers, as opposed to "sources," which release carbon) on land and in the ocean have become less effective over time. That is, natural sinks that removed about 60% of annual human-caused CO ₂ emissions in 1959 now remove about 55% today.

detailed answer

# data[].attributes.attachment_link.keywords[]
national aeronautics and space administration

# data[].attributes.attachment_link.title
Questions (FAQ) | Facts - Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.description
The amount of anthropogenic carbon dioxide (CO 2) absorbed by Earth's life forms, ocean, and other "sinks" might decrease as time goes by. Natural carbon sinks (the carbon absorbers, as opposed to "sources," which release carbon) on land and in the ocean have become less effective over time.

# data[].attributes.headline
NASA Global Climate Change: How Do We Know

# data[].attributes.subject
NASA Global Climate Change: How Do We Know

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.readable_text
The rate of change since the mid-20th century is unprecedented over millennia.

Earth's climate has changed throughout history. Just in the last 800,000 years, there have been eight cycles of ice ages and warmer periods, with the end of the last ice age about 11,700 years ago marking the beginning of the modern climate era - and of human civilization. Most of these climate changes are attributed to very small variations in Earth's orbit that change the amount of solar energy our planet receives.

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.) Find out more about ice cores (external site).

The current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia. It is undeniable that human activities have produced the atmospheric gases that have trapped more of the Sun's energy in the Earth system. This extra energy has warmed the atmosphere, ocean, and land, and widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred.

Do scientists agree on climate change?

Yes, the vast majority of actively publishing climate scientists - 97 percent - agree that humans are causing global warming and climate change.

detailed answer

Earth-orbiting satellites and new technologies have helped scientists see the big picture, collecting many different types of information about our planet and its climate all over the world. These data, collected over many years, reveal the signs and patterns of a changing climate.

Scientists demonstrated the heat-trapping nature of carbon dioxide and other gases in the mid-19th century. Many of the science instruments NASA uses to study our climate focus on how these gases affect the movement of infrared radiation through the atmosphere. From the measured impacts of increases in these gases, there is no question that increased greenhouse gas levels warm Earth in response.

"Scientific evidence for warming of the climate system is unequivocal."

- Intergovernmental Panel on Climate Change

Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that Earth's climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly 10 times faster than the average rate of warming after an ice age. Carbon dioxide from human activities is increasing about 250 times faster than it did from natural sources after the last Ice Age.

References

References
Header image shows clouds imitating mountains as the sun sets after midnight as seen from Denali's backcountry Unit 13 on June 14, 2019. Credit: NPS/Emily Mesner

# data[].attributes.attachment_link.title
Climate Change Evidence: How Do We Know?

# data[].attributes.attachment_link.description
Vital Signs of the Planet: Global Climate Change and Global Warming. How do we know it's happening? Here's the evidence.

# data[].attributes.attachment_link.title
Ice and Climate | Scripps Institution of Oceanography, UC San Diego

# data[].attributes.attachment_link.description
Scripps researchers, news, and research publications focusing on the polar regions, climate change, sea level rise, and sea ice dynamics.

# data[].attributes.attachment_link.title
Past Climate Change | Scripps Institution of Oceanography, UC San Diego

# data[].attributes.attachment_link.description
© 2018 Log in |Submit a Help Request Terms of Use Scripps Institution of Oceanography,UC San Diego

# data[].attributes.attachment_link.description
Visit NASA's new portal for an in-depth look at the science behind sea level change.

# data[].attributes.headline
Essential Principles of Climate Literacy

# data[].attributes.subject
Essential Principles of Climate Literacy

# data[].attributes.attachment_link.title
The Essential Principles of Climate Literacy

# data[].attributes.attachment_link.description
Climate and energy are complex topics. There are many ways to approach climate and energy depending on the grade level, course topics and instructional method.

# data[].attributes.body
Neil deGrasse Tyson explains Weather vs. Climate (Cosmos: A Spacetime Odyssey)

# data[].attributes.attachment_link.title
Weather Versus Climate Change | Cosmos: A Spacetime Odyssey

# data[].attributes.headline
Center for Western Weather and Water Extremes

# data[].attributes.subject
Center for Western Weather and Water Extremes

# data[].attributes.attachment_link.title
Center for Western Weather and Water Extremes - Center For Western Weather and Water Extremes

# data[].attributes.attachment_link.description
Center For Western Weather and Water Extremes (CW3E) Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive La Jolla, CA 92093 Directions

# data[].attributes.body
Climate Changes Evidence and Causes

# data[].attributes.attachment_link.readable_text
The US National Academy of Sciences and The Royal Society have released " Climate Change: Evidence & Causes," a new publication produced jointly by the two institutions. Written by a UK-US team of leading climate scientists and reviewed by climate scientists and others, the publication is intended as a brief, readable reference document for decision makers, policy makers, educators, and other individuals seeking authoritative information on the some of the questions that continue to be asked.

The publication makes clear what is well-established and where understanding is still developing. It echoes and builds upon the long history of climate-related work from both national academies, as well as on the newest climate-change assessment from the United Nations' Intergovernmental Panel on Climate Change. It touches on current areas of active debate and ongoing research, such as the link between ocean heat content and the rate of warming.

# data[].attributes.attachment_link.description
The US National Academy of Sciences and The Royal Society have released " Climate Change: Evidence & Causes," a new publication produced jointly by the two institutions.

# data[].attributes.headline
NPR's "It's all About Carbon" Video Series

# data[].attributes.subject
NPR's "It's all About Carbon" Video Series

# data[].attributes.body
Video's 2-5 are linked at the end of the article

# data[].attributes.attachment_link.readable_text
When the subject is global warming, our mood is usually "uh-oh." Which makes sense, because a warmer Earth will lead to all kinds of disruptions and expensive adjustments that we could do without.

But there is another way to think about all of this.

What we have done here is a chemistry lesson, one that begins with the elemental cause of global warming: the behavior of the carbon atom.

And since carbon atoms are rather small, we have turned our atom into a cartoon. Just so you can see it better.

This is the introductory segment of a five-part series that explains how carbon atoms form bonds, break apart and create the conditions that can lead to global warming. Since most of us are beginners when it comes to elemental chemistry, this is a lesson in five, easy-to-grasp steps. And grasping, by the way, is a big part of our story.

I know a lot of chemistry teachers may happen by, so let me say, right from the start that this is not even remotely hard science; this is a whet-your-appetite exercise that we hope will get lots and lots of people, especially people who don't rush to chemistry class, familiar with the root causes of our warming problem.

In this, the first lesson, we introduce our atom.

You may be surprised to know that you, the person reading this, are to a significant degree a carbon-based organism.

So are your friends, your pets, your plants, and every living thing on Earth.

And there's a reason for that, which we get to in the next episode: It's About Bonds.

# data[].attributes.attachment_link.description
To get to the heart of the global warming story, you've got to look past the polar bears and melting glaciers. Because the scientific explanation for climate change depends to a very large degree on the behavior of one very particular atom: carbon. In five animated episodes, Robert Krulwich explains why it's all about carbon.

# data[].attributes.headline
Yale's Climate Change Communication Site

# data[].attributes.subject
Yale's Climate Change Communication Site

# data[].attributes.attachment_link.provider_name
Yale Program on Climate Change Communication

# data[].attributes.attachment_link.readable_text
Politics and Global Warming: March 2018

Majority of Americans think global warming is happening

Scientific consensus message effectiveness

Americans Support Climate Education

Global Warming's Six Americas

Politics and Global Warming: March 2018

Majority of Americans think global warming is happening

Scientific consensus message effectiveness

Americans Support Climate Education

Global Warming's Six Americas

# data[].attributes.attachment_link.title
The Yale Program on Climate Change Communication

# data[].attributes.attachment_link.description
Politics and Global Warming: March 2018 Majority of Americans think global warming is happening Scientific consensus message effectiveness Americans Support Climate Education Global Warming's Six Americas Politics and Global Warming: March 2018 Majority of Americans think global warming is happening Scientific consensus message effectiveness Americans Support Climate Education Global Warming's Six Americas

# data[].attributes.headline
NOAA National Climate Assessment (NCA) Teaching Resources

# data[].attributes.subject
NOAA National Climate Assessment (NCA) Teaching Resources

# data[].attributes.attachment_link.title
2014 National Climate Assessment Resources for Educators | NOAA Climate.gov

# data[].attributes.attachment_link.description
Explore a series of guides for educators that focus on the regional chapters of the Assessment Report, helping to unpack the key messages of each region and point to related, high-quality online resources.

# data[].attributes.headline
Marine Activities, Resources & Education

# data[].attributes.subject
Marine Activities, Resources & Education

# data[].attributes.body
Look for free resources, videos, simulations for 3-5 and 6-8

# data[].attributes.attachment_link.title
MARE | Marine Activities, Resources & Education

# data[].attributes.attachment_link.description
A program of the Lawrence Hall of Science that seeks to increase ocean literacy through informal and formal education initiatives

# data[].attributes.headline
Southern CA Coastal Ocean Observing System (SCCOOS) Data System

# data[].attributes.subject
Southern CA Coastal Ocean Observing System (SCCOOS) Data System

# data[].attributes.body
SCCOOS data for El Nino, Red Algae, Oceanic Acidification, Surface Currents, Sea Temperature, etc.

# data[].attributes.body
EPA

# data[].attributes.attachment_link.readable_text
Environmental justice (EJ) is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation and enforcement of environmental laws, regulations and policies.

Fair treatment means no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies.

Meaningful involvement means:

People have an opportunity to participate in decisions about activities that may affect their environment and/or health;

The public's contribution can influence the regulatory agency's decision;

Community concerns will be considered in the decision making process; and

Decision makers will seek out and facilitate the involvement of those potentially affected.

Read the accomplishment reports to learn more about the progress that the EPA has made in advancing environmental justice principles? Click here to read annual progress reports on the Agency's most recent EJ accomplishments.

"Whether by conscious design or institutional neglect, communities of color in urban ghettos, in rural 'poverty pockets,' or on economically impoverished Native-American reservations face some of the worst environmental devastation in the nation." Dr. Robert Bullard

# data[].attributes.attachment_link.title
Learn About Environmental Justice | US EPA

# data[].attributes.attachment_link.description
Environmental justice (EJ) is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation and enforcement of environmental laws, regulations and policies. Fair treatment means no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies.

# data[].attributes.attachment_link.readable_text
This is the last of three dispatches from a New York Times reporting trip to Antarctica.

From the air, the Ross Ice Shelf looks like a vast white plain extending to the horizon. The monochromatic landscape is relieved only occasionally by rocks poking through, or by deep crevasses in the ice itself.

Only at its edge does the ice shelf become something more dramatic: a spectacular sheer cliff rising 100 feet above the ocean and extending 900 feet below the surface. From that cliff edge, icebergs occasionally calve away, completing a thousand-year journey of the ice from land to sea.

Scientists are racing to understand what is happening to the Ross Ice Shelf - and the rest of Antarctica - as the planet warms around it. They are trying to map the thickness of the ice and the shape of the sea floor beneath it in an effort to gauge how vulnerable the shelf may be to collapse, and how soon that could happen.

Scientists are also trying to measure the role of human-caused climate change in weakening some parts of the West Antarctic ice sheet, and to fathom how damaging the seas around the continent might prove to be as they warm over time.

The answers carry profound implications for humanity. In the scientists' worst-case computer simulations, continued global warming will cause the Ross Ice Shelf to weaken and collapse starting as early as the middle of this century.

Right now, the shelf works like a giant bottle-stopper that slows down ice trying to flow from the land into the sea. If it collapses, the ice could flow into the ocean more rapidly, an effect that has already happened on a much smaller scale in other areas of Antarctica.

The most vulnerable parts of the West Antarctic ice sheet could raise the sea level by 10 to 15 feet, inundating many of the world's coastal cities, though most scientists think that would take well over a century, or perhaps longer. They are worried about a possible rise of as much as six feet by the end of this century.

Whether these alarming forecasts ultimately prove right depends in part on the shape of the sea floor beneath the ice shelf, and in particular on whether it has deep channels that can funnel warming ocean water under the ice shelf and attack the West Antarctic ice sheet from below. A different undersea topography - high ridges of rock, for example - may keep warmer water out, stabilizing the ice sheet, possibly for hundreds of years.

"We're hoping to figure out how warm water can get to the edge of the ice sheet," said Robin E. Bell, head of the Columbia University laboratory that sent a team to survey the Ross Ice Shelf late last year. "What are the sort of hidden roads it can go on?"

As they flew back and forth across the vast white landscape in December, the Columbia scientists used some of the world's most sophisticated geophysical instruments to see into and beneath the ice. As the hours-long flights wore on, the scientists took turns napping, knitting or eating cold pizza, but at all times, somebody kept close watch on the instruments.

Kirsty J. Tinto, the scientist leading the field team, loved watching as the measurements stripped away the illusion that the ice was just a flat, boring pancake.

"You take a slice through it and you can see a thousand years of history, a hundred million years of history," she said.

The Ross Ice Shelf appears stable now, so the Columbia project will function somewhat like a doctor's baseline X-ray - a starting point for comparison if the ice starts to deteriorate.

Satellite evidence suggests that this is already happening in other parts of West Antarctica, and many scientists believe that relatively warm ocean water is the culprit. "It's kind of a blowtorch on the underside of the ice shelf," said Robert A. Bindschadler, a retired NASA climate scientist.

But the story is not straightforward, and the warmer water attacking the ice has not been linked to global warming - at least not directly. The winds around the continent seem to be strengthening, stirring the ocean and bringing up a layer of warmer water that has most likely been there for centuries.

Are those stronger winds tied to human-caused global warming? Some scientists think so, but others say the case is unproven. "We're not sure because we don't have enough data, for long enough, to separate signal from noise," said Eric J. Steig, a scientist at the University of Washington who has studied temperature trends in Antarctica.

Though the role of global warming is unclear now, it is likely to be a factor in the relatively near future. Many experts think warmer air temperatures could start to weaken the ice of West Antarctica from above, even as warmer ocean water attacks it from below.

The warmer water seems to be doing the most damage to a series of glaciers that flow into a region of West Antarctica called the Amundsen Sea. Satellites have identified the most rapid loss of ice there, raising a critical question: Has an unstoppable collapse of the ice sheet already begun?

The Amundsen Sea region is one of the remotest parts of the continent, far from American and British research bases. Working together, the two countries are planning to devote tens of millions of dollars to getting better measurements there, having decided that it is imperative to begin answering questions about the region's potential collapse.

For instance, scientists need to know a lot more about the ground beneath the glaciers there. Is it slick mud that may allow the ice to flow much faster, or hard rock that may slow down the ice even in a warmer world?

"What we need to know is really the details of what is occurring where the ice, ocean and land all come together," said Ted A. Scambos, a University of Colorado scientist who is helping to plan the joint research effort.

Unraveling the answers, and gaining a better understanding of how Antarctica's ice has waxed and waned in the past, may offer a rough guide to the changes that human-caused global warming could wreak in the future.

Already, scientists know enough to be concerned. About 120,000 years ago, before the last ice age, the planet went through a natural warm period, with temperatures similar to those expected in coming decades.

The sea level was 20 to 30 feet higher than it is today, implying that the ice sheets in both Greenland and Antarctica must have partly disintegrated, a warning of what could occur in the relatively near future if the heating of the planet continues unchecked.

But some research suggests that a catastrophe might not yet be inevitable. In a study last year, Robert M. DeConto of the University of Massachusetts, Amherst, and David Pollard of Pennsylvania State University used their computer model to predict what would happen if emissions were reduced sharply over the next few decades, in line with international climate goals.

Under the most ambitious scenarios, they found a strong likelihood that Antarctica would remain fairly stable.

"There's still a chance that all hell will break loose," Dr. DeConto said. "But the model is suggesting there's a way to reduce the risk of a big sea-level rise from Antarctica."

In the immersive video below, we fly past a six-mile iceberg, a tiny fragment of the Ross Ice Shelf.

# data[].attributes.attachment_link.title
Miles of Ice Collapsing Into the Sea (Published 2017)

# data[].attributes.attachment_link.description
This is the last of three dispatches from a New York Times reporting trip to Antarctica. From the air, the Ross Ice Shelf looks like a vast white plain extending to the horizon. The monochromatic landscape is relieved only occasionally by rocks poking through, or by deep crevasses in the ice itself.

# data[].attributes.body
Multiple levels of detail for many of the most common misconceptions and mistruths about climate change.

# data[].attributes.attachment_link.title
Global Warming and Climate Change skepticism examined

# data[].attributes.attachment_link.description
Examines the science and arguments of global warming skepticism. Common objections like 'global warming is caused by the sun', 'temperature has changed naturally in the past' or 'other planets are warming too' are examined to see what the science really says.

# data[].attributes.headline
San Diego Endangered and Threatened Species

# data[].attributes.subject
San Diego Endangered and Threatened Species

# data[].attributes.attachment_link.readable_text
The San Diego Audubon Society utilizes a combination of habitat restoration, citizen science, advocacy, education, and community outreach activities to support the recovery of target species within metropolitan San Diego. The following species are just some of the birds that we're helping to protect.

California Least Tern(Sterna antillarum browni)

The California Least Tern is an endangered migratory shorebird that nests on our beaches within a limited range from northern Baja California to San Francisco Bay. The Least Tern needs cleared, sandy areas for nesting and depends on estuaries, lagoons, and other open water areas for hunting small fish. Terns nest in colonies which helps them work together to defend nests and chicks from predators such as American Crows, Gulls, cats, and snakes. San Diego County supports 60% of the breeding population of this bird at 12 sites including the Tijuana Estuary, the Sweetwater Marsh National Wildlife Refuge, Mission Bay, and our coastal lagoons.
Fun Fact: Least Terns defend their nesting colony against a predator by flying up, calling loudly, and pooping on their target!
How we're helping

SDAS is working in Mission Bay and San Diego Bay to restore Least Tern nesting habitat. We currently have active projects at the D-Street Fill in the Sweetwater Marsh National Wildlife Refuge and at Mariner's Point in Mission Bay. This year, we plan to focus our conservation efforts on additional nesting sites in Mission Bay through habitat restoration and citizen science projects.

Learn More
Fish and Wildlife Services Species Profile
Western Snowy Plover (Charadrius alexandrinus nivosus)

The Western Snowy Plover is a threatened shorebird that is found on flat, open coastal beaches, in dunes, and near stream mouths. Similar to the Least Tern, the Snowy Plover nests in a shallow scrape in sand, usually lined with small pebbles and shells. Snowy Plovers are year round residents of San Diego County and nest along our coastline with breeding concentrations in Camp Pendleton and the Silver Strand. The plovers nest in loose colonies from early spring to mid-fall. Incubation duties are shared by both parents - the male keeps the eggs warm at night, while the female is responsible for day duty. Similar to other nesting shorebirds such as the Least Tern, Snowy Plovers are threatened due to human disturbance, predation, and habitat loss.
Fun Fact: Snowy Plover chicks are precocial, meaning they are able to walk just hours after birth!
How we're helping:

SDAS has collaborated with California State Parks to carry out a children's signage and education program called Share the Shore. This program engaged local schoolchildren in the creation of educational signage while teaching them about the plover. Signage is currently displayed at Silver Strand State Beach and the Tijuana Slough and has proved to be quite effective in deterring human disturbances near nesting areas.

Learn More

Westernsnowyplover.org
California State Parks Western Snowy Plover Profile

Coastal Cactus Wren (Campylorhynchus brunneicapillus sandiegensis)

The Coastal Cactus Wren is a resident, non-migratory subspecies of Cactus Wren that is listed as a Species of Special Concern. Habitat loss, degradation, and fragmentation are the most critical management issues facing this species, which have been more recently exacerbated by the 2007 wildfires which burned much of the cactus scrub that they depend on. The wrens nest in stands of prickly pear or cholla cactus throughout coastal San Diego County, with concentrations in southern Camp Pendleton/Fallbrook Naval Weapons Station, Lake Hodges/San Pasqual, Lake Jennings, and Sweetwater/Otay.
Fun Fact: Coastal Cactus Wrens are home bodies, maintaining their nests in stands of prickly pear or cholla cactus year-round.
How we're helping:

SDAS is coordinating volunteers to assist with cactus wren habitat assessments in the San Dieguito River Valley and other locations throughout the County. These assessments will support the prioritization of cactus scrub restoration and a USGS study that will examine dispersal of cactus wrens.

Learn more:
California Partners in Flight Coastal Shrub and Chaparral Bird Conservation Plan
Light-footed Ridgway's Rail (Rallus longirostris levipes)

The Light-footed Ridgway's Rail (formerly known as a Clapper Rail) is a year round resident of San Diego County's coastal salt marshes. As a result of the loss of over 90% of southern California's coastal wetlands, this species has been listed as federally-endangered for over 40 years. Ridgway's Rails prefer to nest in tidal marshes dominated by cordgrass. There are an estimated 100 pairs in San Diego County with breeding populations scattered throughout coastal lagoons and estuaries. The Tijuana River estuary is an especially critical site, supporting a record 80 pairs in 1999.
Fun Fact: The Clapper Rail's nest is constructed from hollow cordgrass stems which are weaved around upright cordgrass stems - this allows the nest to float, while secured in place, with the changing tides.
How we're helping:

SDAS has collaborated with the UC Natural Reserve System and the Ocean Discovery Institute to carry out an invasive mangrove removal project at the Northern Wildlife Preserve in Mission Bay. This invasive plant posed a threat to the Clapper Rail by displacing native cordgrass and negatively impacting the quality of the salt marsh habitat. SDAS has also partnered with the Tijuana National Estuarine Research Reserve, California State Parks, and the US Fish & Wildlife Service to carry out a vegetation monitoring program that established baseline data to evaluate changes in habitat, including salt marsh, to inform future management actions.

Learn more:
Fish and Wildlife Services Species Profile

# data[].attributes.attachment_link.description
The San Diego Audubon Society utilizes a combination of habitat restoration, citizen science, advocacy, education, and community outreach activities to support the recovery of target species within metropolitan San Diego. The following species are just some of the birds that we're helping to protect.

# data[].attributes.headline
LA Times Article about placing animals on the 'Threatened" list based on Climate Change Prediction Models

# data[].attributes.subject
LA Times Article about placing animals on the 'Threatened" list based on Climate Change Prediction Models

# data[].attributes.attachment_link.readable_text
The bearded seals congregate on ice floes over shallow waters, where they give birth to pups and nurse. The floes give the nursing mothers close access to food sources - organisms on the ocean floor - and enable the pubs to learn to dive, swim and hunt away from their predators, the court said.

# data[].attributes.attachment_link.title
Species may be listed as threatened based on climate change projections, court says

# data[].attributes.attachment_link.description
The bearded seals congregate on ice floes over shallow waters, where they give birth to pups and nurse. The floes give the nursing mothers close access to food sources - organisms on the ocean floor - and enable the pubs to learn to dive, swim and hunt away from their predators, the court said.

# data[].attributes.attachment_link.readable_text
Standing on the shores of Netarts Bay in Oregon on a sunny fall morning, it's hard to imagine that the fate of the oysters being raised here at the Whiskey Creek Shellfish Hatchery is being determined by what came out of smokestacks and tailpipes in the 1960s and '70s. But this rural coastal spot and the shellfish it has nurtured for centuries are a bellwether of one of the most palpable changes being caused by global carbon dioxide emissions - ocean acidification.

It was here, from 2006 to 2008, that oyster larvae began dying dramatically, with hatchery owners Mark Wiegardt and his wife, Sue Cudd, experiencing larvae losses of 70 to 80 percent. "Historically we've had larvae mortalities," says Wiegardt, but those deaths were usually related to bacteria. After spending thousands of dollars to disinfect and filter out pathogens, the hatchery's oyster larvae were still dying.

Finally, the couple enlisted the help of Burke Hales, a biogeochemist and ocean ecologist at Oregon State University. He soon homed in on the carbon chemistry of the water. "My wife sent a few samples in and Hales said someone had screwed up the samples because the [dissolved CO2 gas] level was so ridiculously high," says Wiegardt, a fourth-generation oyster farmer. But the measurements were accurate. What the Whiskey Creek hatchery was experiencing was acidic seawater, caused by the ocean absorbing excessive amounts of CO2 from the air.

Ocean acidification - which makes it difficult for shellfish, corals, sea urchins, and other creatures to form the shells or calcium-based structures

The region's thriving oyster hatcheries have had to scramble to adapt to these increases in acidity.

they need to live - was supposed to be a problem of the future. But because of patterns of ocean circulation, Pacific Northwest shellfish are already on the front lines of these potentially devastating changes in ocean chemistry. Colder, more acidic waters are welling up from the depths of the Pacific Ocean and streaming ashore in the fjords, bays, and estuaries of Oregon, Washington, and British Columbia, exacting an environmental and economic toll on the region's famed oysters.

For the past six years, wild oysters in Willapa Bay, Washington, have failed to reproduce successfully because corrosive waters have prevented oyster larvae from forming shells. Wild oysters in Puget Sound and off the east coast of Vancouver Island also have experienced reproductive failure because of acidic waters. Other wild oyster beds in the Pacific Northwest have sustained losses in recent years at the same time that scientists have been measuring alarmingly corrosive water along the Pacific coast.

The region's thriving oyster hatcheries have had to scramble to adapt to these increases in acidity, which pose a threat to their very existence. Some of the largest operations, such as Whiskey Creek, are buffering the water in which they grow their larvae, essentially giving their tanks a dose of antacid in the form of sodium bicarbonate.

While the operation may look modest - a handful of small buildings just yards from the shore of a wide bay - Whiskey Creek is one of the largest suppliers of oyster seed on the West Coast. Its baby oysters are grown all along the U.S. Pacific coast, where the oyster industry is currently valued at about $73 million annually. Washington's Taylor Shellfish Hatchery - the country's largest producer of farmed shellfish and one of the largest oyster producers - has also experienced dramatic losses. Its hatchery on Hood Canal, which has had some of the Pacific Northwest's highest levels of ocean acidification, experienced the loss of about three-quarters of its oyster larvae before the owners began buffering the high acidity.

Together, Whiskey Creek and Taylor Shellfish, which also raises clams and mussels, account for most of the West Coast's commercial shellfish production. Oysters are the biggest product, making up more than 80 percent of the Pacific coast shellfish produced and more than 60 percent of the revenue. According to industry and federal officials, the West Coast oyster industry generates about 3,000 jobs and has a total annual economic impact of about $207 million - significant numbers for their coastal communities.

The situation at the hatcheries has improved substantially in the past couple of years, thanks largely to an ongoing, intensive scientific monitoring effort and to measures to control the pH of seawater in the tanks where oyster larvae are raised. But ocean acidification continues apace, which makes understanding what's been happening to Whiskey Creek oysters vital to grasping what will eventually threaten every ocean organism that builds a shell or coral branch.

Because of the way seawater circulates around the world, the deep water now washing ashore in Oregon and Washington is actually 30 to 50 years old and absorbed its CO2 long before the fall of the Berlin Wall. This time lag is important because oceans absorb about 50 percent of the CO2 released by burning fossil fuels, emissions that have been rising dramatically in recent decades. According to the National Oceanic and Atmospheric Administration (NOAA) ocean acidity has increased approximately 30 percent since the Industrial Revolution, and if we continue our current rate of carbon emissions, global oceans could be 150 percent more acidic by the end of the century than they have been for 20 million years.

"This problem is real," says Hales. "There are measurable human impacts."
Click to enlarge

Once absorbed by seawater, CO2 undergoes chemical reactions that make the water more acidic, says Richard Feely, a senior scientist at NOAA's Pacific Marine Environmental Laboratory and an expert in the ocean's carbon chemistry. The chemical reactions that lower the ocean's pH also reduce the availability of the kind of calcium carbonate that a variety of sea creatures need to build shells. On a 2007 research cruise along the Pacific Coast from British Columbia to Baja California, Feely discovered that "corrosive waters were everywhere we looked."

When seasonal wind patterns change in spring, north winds create upwellings of deep and more acidic seawater off the Pacific Northwest coast. These waters - with their lowered pH and lack of available calcium carbonate in the form of what's called aragonite - are what have been killing the oyster larvae. The availability of aragonite is particularly vital at an oyster's earliest stages of development. In the first 24 to 48 hours of an oyster's life, as it forms its first shell, the larvae go from being almost 0 percent shell to at least 70 percent shell before they begin to grow more tissue, explains George Waldbusser, assistant professor of ocean ecology and biochemistry at Oregon State University's College of Oceanic and Atmospheric Sciences. Lower aragonite saturation means the tiny larvae - much smaller than a poppy seed - need to expend more energy to make their shells.

"If too much energy is used at one stage, they may not be able to survive to a subsequent stage or overcome the stress," says Waldbusser.

Acidic water sometimes kills oyster larvae outright, so that they fail to survive past the egg stage. At other times, the eggs hatch, but larvae fail after a week or two.

"A lot is happening to an egg in the first 24 hours," says Benoit Eudeline, chief scientist at the Taylor Shellfish Hatchery. "It goes from what's essentially a blob to a creature with a shell, a digestive tract, organs. The oyster has to use a lot of aragonite to make its early shell and there seems

'If too much energy is used at one stage, larvae may not be able to survive to a subsequent stage,' says an expert.

to be a strong correlation between aragonite saturation and survival of larvae at a later stage."

Waldbusser and colleagues are now researching the impacts of the stress induced by low aragonite saturation - how it may be affecting the oyster larvae's use of its food reserves, and how it may impact development. "At this stage they're floating around and eating as much as they can," explains Christopher Sabine, director of NOAA's Pacific Marine Environmental Laboratory. "Anything that's going to take energy away from shell-building is going to cost them."
MORE FROM YALE e360 An Ominous Warning on the
Effects of Ocean Acidification
In response to the devastating die-off of larvae from 2006 to 2008 - and with the help of Hales, Waldbusser, and other scientists - Whiskey Creek and Taylor Shellfish began a program of ongoing monitoring to help avoid the intake of acidic water. Particularly at Netarts Bay, where the deep ocean water is on shore in early morning, they discovered they could improve pH conditions by varying the time of day they took water into their tanks. A better, less acidic time to pull in water is later in the day, after growth of phytoplankton has been stimulated by sunlight, thus soaking up some of the excess CO2. Buffering the acid also was crucial. A half-million dollars in federal funds has helped cover the expensive work of monitoring and controlling the seawater chemistry.

At the Taylor Shellfish Hatchery, where water takes much longer than it does at Netarts to move in and out of the bay, organic matter - dead algae for example - can build up, die, and become food for bacteria that use up oxygen and further increase CO2 concentrations. This underscores the fact that controlling the flow of excess nutrients into the ocean, such as fertilizers and sewage, can to some degree offset the impacts of growing acidity.

A 2010 study said the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, science writer Carl Zimmer reported, current changes in ocean chemistry may portend a new wave of die-offs.

Feely said problems with ocean acidification are also starting to be seen on the U.S.'s Atlantic coast and in Australia. Agricultural runoff and sewage have been taking a toll on the once-thriving oyster business in the Chesapeake Bay, and now rising ocean acidity is further exacerbating the problems of CO2-laden waters there. But for shellfish growers in the Pacific Northwest, these impacts are already too clear. As Bill Dewey of Taylor Shellfish put it, Pacific Northwest oysters may be "the canary in the coal mine."

Yet on a November morning, with the snow-capped peaks of the Olympic Mountains just visible through the fog, the landscape around Taylor Shellfish looks much as it always has: the sea, the mountains, and a shore lined with fir trees. But as Dewey understands, the green-gray water is changing in a way it hasn't for eons - changes that will be with us well into the next century, and possibly longer.

"We have to find a way in our industry to adapt," says Dewey.

# data[].attributes.attachment_link.title
Northwest Oyster Die-offs Show Ocean Acidification Has Arrived

# data[].attributes.attachment_link.description
The acidification of the world's oceans from an excess of CO2 has already begun, as evidenced recently by the widespread mortality of oyster larvae in the Pacific Northwest. Scientists say this is just a harbinger of things to come if greenhouse gas emissions continue to soar.

# data[].attributes.attachment_link.readable_text
The history of conservation is a story of many victories in a losing war. Having served on the boards of global conservation organizations for more than 30 years, I know very well the sweat, tears and even blood shed by those who dedicate their lives to saving species. Their efforts have led to major achievements, but they have been only partly successful.

The extinction of species by human activity continues to accelerate, fast enough to eliminate more than half of all species by the end of this century. Unless humanity is suicidal (which, granted, is a possibility), we will solve the problem of climate change. Yes, the problem is enormous, but we have both the knowledge and the resources to do this and require only the will.

The worldwide extinction of species and natural ecosystems, however, is not reversible. Once species are gone, they're gone forever. Even if the climate is stabilized, the extinction of species will remove Earth's foundational, billion-year-old environmental support system. A growing number of researchers, myself included, believe that the only way to reverse the extinction crisis is through a conservation moonshot: We have to enlarge the area of Earth devoted to the natural world enough to save the variety of life within it.

The formula widely agreed upon by conservation scientists is to keep half the land and half the sea of the planet as wild and protected from human intervention or activity as possible. This conservation goal did not come out of the blue. Its conception, called the Half-Earth Project, is an initiative led by a group of biodiversity and conservation experts (I serve as one of the project's lead scientists). It builds on the theory of island biogeography, which I developed with the mathematician Robert MacArthur in the 1960s.

Island biogeography takes into account the size of an island and its distance from the nearest island or mainland ecosystem to predict the number of species living there; the more isolated an ecosystem, the fewer species it supports. After much experimentation and a growing understanding of how this theory works, it is being applied to the planning of conservation areas.

So how do we know which places require protection under the definition of Half-Earth? In general, three overlapping criteria have been suggested by scientists. They are, first, areas judged best in number and rareness of species by experienced field biologists; second, "hot spots," localities known to support a large number of species of a specific favored group such as birds and trees; and third, broad-brush areas delineated by geography and vegetation, called ecoregions.

All three approaches are valuable, but applying them in too much haste can lead to fatal error. They need an important underlying component to work - a more thorough record of all of Earth's existing species. Making decisions about land protection without this fundamental knowledge would lead to irreversible mistakes.

The most striking fact about the living environment may be how little we know about it. Even the number of living species can be only roughly calculated. A widely accepted estimate by scientists puts the number at about 10 million. In contrast, those formally described, classified and given two-part Latinized names (Homo sapiens for humans, for example) number slightly more than two million. With only about 20 percent of its species known and 80 percent undiscovered, it is fair to call Earth a little-known planet.

Paleontologists estimate that before the global spread of humankind the average rate of species extinction was one species per million in each one- to 10-million-year interval. Human activity has driven up the average global rate of extinction to 100 to 1,000 times that baseline rate. What ensues is a tragedy upon a tragedy: Most species still alive will disappear without ever having been recorded. To minimize this catastrophe, we must focus on which areas on land and in the sea collectively harbor the most species.

Building on new technologies, and on the insight and expertise of organizations and individuals who have dedicated their lives the environment, the Half-Earth Project is mapping the fine distribution of species across the globe to identify the places where we can protect the highest number of species. By determining which blocks of land and sea we can string together for maximum effect, we have the opportunity to support the most biodiverse places in the world as well as the people who call these paradises home. With the biodiversity of our planet mapped carefully and soon, the bulk of Earth's species, including humans, can be saved.

By necessity, global conservation areas will be chosen for what species they contain, but in a way that will be supported, and not just tolerated, by the people living within and around them. Property rights should not be abrogated. The cultures and economies of indigenous peoples, who are de facto the original conservationists, should be protected and supported. Community-based conservation areas and management systems such as the National Natural Landmarks Program, administered by the National Park Service, could serve as a model.

To effectively manage protected habitats, we must also learn more about all the species of our planet and their interactions within ecosystems. By accelerating the effort to discover, describe and conduct natural history studies for every one of the eight million species estimated to exist but still unknown to science, we can continue to add to and refine the Half-Earth Project map, providing effective guidance for conservation to achieve our goal.

The best-explored groups of organisms are the vertebrates (mammals, birds, reptiles, amphibians, fishes), along with plants, especially trees and shrubs. Being conspicuous, they are what we familiarly call "wildlife." A great majority of other species, however, are by far also the most abundant. I like to call them "the little things that run the world." They teem everywhere, in great number and variety in and on all plants, throughout the soil at our feet and in the air around us. They are the protists, fungi, insects, crustaceans, spiders, pauropods, centipedes, mites, nematodes and legions of others whose scientific names are seldom heard by the bulk of humanity. In the sea and along its shores swarm organisms of the other living world - marine diatoms, crustaceans, ascidians, sea hares, priapulids, coral, loriciferans and on through the still mostly unfilled encyclopedia of life.

Do not call these organisms "bugs" or "critters." They too are wildlife. Let us learn their correct names and care about their safety. Their existence makes possible our own. We are wholly dependent on them.

With new information technology and rapid genome mapping now available to us, the discovery of Earth's species can now be sped up exponentially. We can use satellite imagery, species distribution analysis and other novel tools to create a new understanding of what we must do to care for our planet. But there is another crucial aspect to this effort: It must be supported by more "boots on the ground," a renaissance of species discovery and taxonomy led by field biologists.

Within one to three decades, candidate conservation areas can be selected with confidence by construction of biodiversity inventories that list all of the species within a given area. The expansion of this scientific activity will enable global conservation while adding immense amounts of knowledge in biology not achievable by any other means. By understanding our planet, we have the opportunity to save it.

As we focus on climate change, we must also act decisively to protect the living world while we still have time. It would be humanity's ultimate achievement.

A version of this article appears in print on , on Page SR10 of the New York edition with the headline: The 8 Million Species We Don't Know. Order Reprints | Today's Paper | Subscribe

# data[].attributes.attachment_link.title
Opinion | The 8 Million Species We Don't Know

# data[].attributes.attachment_link.description
The history of conservation is a story of many victories in a losing war. Having served on the boards of global conservation organizations for more than 30 years, I know very well the sweat, tears and even blood shed by those who dedicate their lives to saving species.

# data[].attributes.body
PBS Sound of Climate Change

# data[].attributes.attachment_link.readable_text
Climate change is a gradual process, driven by invisible pollution. So it can be hard to wrap your brain around.

But atmospheric scientists at the University of Washington have made it possible to listen to the planet changing.

You may never have heard of the Keeling Curve, though it touches the lives of everyone on earth. It traces how much carbon dioxide is in the sky. Scientists have been watching it curve upward since the 1950s, when Scripps geochemist Charles Keeling started his measurements atop Mauna Loa, high above Hawaii's Big Island, in the middle of the Pacific Ocean. The Keeling Curve has become one of the most widely used indicators of humans' impact on the planet.

Here's what it sounds like:

Graduate student Judy Twedt and professor Dargan Frierson converted half a century of data into about a minute of sound. Twedt assigned each monthly CO2 measurement a different pitch, spanning the same range as the notes on a piano.

"Lower notes correspond with lower carbon dioxide concentrations," Frierson said. "You can hear, there's a natural up and down."

As plants breathe in CO2 each northern-hemisphere summer and breathe it out each winter, the musical pitch rises and falls.

As smokestacks, tailpipes and deforestation add more CO2, the whole cycle keeps rising, taking the earth's temperature along with it.

"Time series are particularly suitable for listening because you hear things in time," Twedt said. "It's a better medium than looking at something all at once."

Frierson, a scientist and a musician, added drums and made a music video out of the data.

"I think everything should have a drum track with it. Everything would sound better," Frierson said. "The hope is more people would listen to it if it's a little bit fun."

Climate scientists at UW have been trying some unscientific methods to get people to pay attention to the climate. They've made climate video games and even a film noir detective series about El Niño.

Fifty climate scientists at UW, including Frierson, have stepped into the political arena by endorsing a carbon tax measure on the Washington ballot this fall.

"I am a scientist, but I'm also a citizen of the world," Frierson said. "I have a daughter who's going to be experiencing a different climate because of the rise of CO2 here."

The carbon tax, which would be the nation's first, has drawn opposition from the Association of Washington Business, with cement, aluminum and paper companies making the biggest donations to its $400,000 effort to stop Initiative 732.

The measure has split the state's environmental movement over whether it does enough to fight climate change and poverty.

In addition to imposing a carbon tax, I-732 would lower the state's sales tax (a tax that hits the poor harder than higher-income taxpayers) and offer tax rebates to low-income families and manufacturers.

Unlike most measures on the Washington ballot this year, I-732 has had few large donors, and the grassroots activists with CarbonWA had little funding left after their campaign's expensive signature-gathering phase. But 11th-hour fundraising in mid-October by Audubon Washington, one of the few large environmental groups to lend support to the measure, has brought in $740,000, with the largest donation of $250,000 coming from Texas billionaire couple John and Laura Arnold.

This report first appeared on EarthFix's website. EarthFix is a public media project of Oregon Public Broadcasting and Boise State Public Radio, Idaho Public Television, KCTS 9 Seattle, KUOW Puget Sound Public Radio, Northwest Public Radio and Television, Southern Oregon Public Television and the Corporation for Public Broadcasting.

# data[].attributes.attachment_link.title
Listen to 58 years of climate change in one minute

# data[].attributes.attachment_link.description
Climate change is a gradual process, driven by invisible pollution. So it can be hard to wrap your brain around. But atmospheric scientists at the University of Washington have made it possible to listen to the planet changing. You may never have heard of the Keeling Curve, though it touches the lives of everyone on earth.

# data[].attributes.attachment_link.readable_text
Why is Oxygen Important to Life in the Ocean?

Oxygen is necessary to support life on Earth. Oxygen makes up about 21% of the air we breathe and half of this oxygen is produced by phytoplankton in the ocean. All aerobic life requires oxygen to produce energy. In water, oxygen is found in a dissolved form and is much more limiting. For this reason, we measure dissolved oxygen in water not in % but in units of umol/kg. The highest concentrations of dissolved oxygen in the ocean are found within the surface mixed layer at concentrations of > 200 umol/kg. Below the surface mixed layer, oxygen concentrations are lower due to respiration by all of the trillions of organisms and bacteria that live in the water column.

What is Ocean Deoxygenation?

Ocean deoxygenation refers to the loss of oxygen from the oceans due to climate change (Keeling et al. 2010). Long-term ocean monitoring shows that oxygen concentrations in the ocean have declined during the 20th century, and the new IPCC 5th Assessment Report (AR5 WG1) predicts that they will decrease by 3-6% during the 21st century in response to surface warming. While 3-6% doesn't seem like much, this decrease will be felt acutely in hypoxic and suboxic areas, where oxygen is already limiting. "Hypoxic" areas are defined as regions where oxygen limitation is detrimental to most organisms. This threshold differs across the world, but is usually defined as anything below 60 umol/kg. Hypoxic zones have oxygen concentrations 70-90% lower than the mean surface concentrations. "Suboxic" areas are areas where oxygen is so low (less than 5 umol/kg) that most life cannot be sustained and significant biogeochemical changes occur due to altered water chemistry. Suboxic zones have oxygen concentrations 98% lower than the mean surface concentrations. A recent study found that a 1°C warming throughout the upper ocean will result in the increase of hypoxic areas by 10% and a tripling of the volume of suboxic waters (Deutsch et al. 2011). To put this in context, a highly optimistic emissions scenario of atmospheric CO2 levels of 550 ppm by 2100 would lead to a 1.2°C warming of the upper ocean (Mora et al. 2013). Therefore, these declines in oxygen are changes we should be prepared to see. An education video on ocean deoxygenation can be viewed here.

How Are Humans Lowering the Oxygen Levels in the Ocean?

Oxygen content in the water is dependent on photosynthesis (produces oxygen), animal respiration (uses oxygen), and physical mixing. Ocean warming is reducing global ocean oxygen content through several key mechanisms (Keeling et al. 2010) including:

Stratification impacts: Anthropogenic warming causes surface waters to become warmer and thereby less dense, leading to a more stratified (layered) water column, which reduces mixing. Other impacts of climate change to the water cycle can also lead to a more stratified water column. These include inputs of freshwater to the ocean from rain, river runoff, or melting ice.

Warming effects: As a physical rule, warmer water holds less oxygen. As the surface waters warm due to climate change, the ocean loses its ability to hold oxygen, leading to an oxygen decline.

Biological effects: Changes to the biological use and production of oxygen can lead to changes in oxygen content in the water. Warmer ocean temperatures increase oxygen demand from organisms. Increased nutrient inputs (either through coastal runoff or through upwelling) also lead to more oxygen depletion at mid-depths (100-1000m).

Circulation changes: Changes in ocean circulation are also implicated with some of the observed declines in dissolved oxygen (Grantham et al. 2004). Slowing circulation and increased upwelling of oxygen-poor deep-water can lead to reductions in oxygen.

Oxygen Minimum Zones Are Expanding with Climate Change

Low oxygen areas are already present in several parts of the world and are increasing in number, volume, and intensity. Eastern boundary currents and upwelling regions occur on the eastern side of ocean basins and support some of the richest fisheries in the world. However, underlying these productive surface waters are extremely oxygen-depleted waters at 100-1000m depths. These are known as oxygen minimum zones (OMZs), which are midwater regions of the ocean that are naturally low in oxygen due to the combined processes of high oxygen use and limited oxygen replenishment (Wyrtki 1962). Already, OMZs make up ~8% of the total oceanic area (Paulmier and Ruiz-Pino 2009). OMZs are now expanding both horizontally and vertically due to climate change, resulting in habitat loss for organisms that are sensitive to low-oxygen concentrations (Gilly et al. 2013). Since the 1960s, the hypoxic area has increased by 4.5 million km2 at depths of 200-700 m in tropical and subtropical waters (Stramma et al. 2010). Meanwhile, off of California, waters at 200-300m have lost 20-30% of their oxygen in the last 25 years (Bograd et al. 2008). OMZ expansion is evident in all tropical ocean basins and throughout the subarctic Pacific, making habitat compression an increasingly global issue.

Fisheries Impacts from Oxygen Minimum Zone Expansion

The expansion of oxygen minimum zones and habitat compression is predicted to impact oceanic commercial fisheries. Already, some species range shifts have been observed due to changes in oxygen content. For example, along the Japanese continental slope decreases in mid-depth oxygen content over the last 60 years have resulted in Pacific cod shifting their distributions to shallower depths (Gilly et al. 2013, Ono et al. 2010). In the tropical Atlantic, blue marlin and tuna have experienced a 15% reduction in vertical habitat between 1960-2010 due to the expansion of oxygen minimum zones (Stramma et al. 2011). While organisms that are intolerant of low oxygen are losing habitat, other organisms are gaining habitat. Off the West Coast of the US, the Humboldt squid has greatly expanded its range, and the range expansion coincides strongly with areas of significant oxygen declines (Gilly et al. 2013).

How Will Oxygen Loss Affect Marine Ecosystems and Humans?

Oxygen plays a key role in structuring marine ecosystems and controls the distribution of essentially all marine organisms (Gilly et al. 2013). For this reason, oxygen loss in the oceans will have significant ecosystem-level consequences. Organisms exhibit a great range in tolerances to low levels of dissolved oxygen. Some are highly tolerant, such as jellyfish and squid, while other groups like fish and crustaceans require higher oxygen levels and are highly vulnerable to oxygen declines (Vacquer and Sunyer 2010). This sensitivity has been seen in many systems. For example, off Southern California mid-water fishes, which are crucial components of the ocean food web, declined 63% between periods of high and low oxygen (Koslow et al. 2011). The vulnerability of fish and crustaceans is also evident by the large fish and crustacean die-offs that have occurred during low oxygen events, including off Oregon's coast (Grantham et al. 2004) and in the Gulf of Mexico. While mortality is a direct impact of oxygen loss, marine organisms can also be indirectly impacted leading to changes in behavior, reproduction, growth and behavior. Together, direct and indirect species-level impacts can lead to significant ecosystem-level consequences such as decreased resilience, stability, and resistance to other anthropogenic stressors such as fishing and pollution. Coastal waters are experiencing significant reductions in oxygen due to nutrient pollution, but these impacts are also exacerbated by climate change. Dead zones, areas where most organisms cannot live due to oxygen limitation, are now reported for more than 479 systems, and since the 1960s, their numbers have doubled approximately every decade (Diaz and Rosenberg 2008). Currently, hypoxia and anoxia are among the most widespread deleterious anthropogenic influences on estuarine and marine environments. As surface waters warm, these low oxygen coastal areas, and the animals that live within them, experience even more oxygen stress. These changes impact the people that depend on these waters for resources.

Need for Attention to Deoxygenation By Policy-Makers

Marine ecosystems provide us with fundamental ecosystems services and changes to these ecosystems leave coastal economies vulnerable. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by the stacked impacts of warming, acidification, and deoxygenation (Mora et al. 2013). Namibia, the Philippines, India, Chile, Peru, and the US are just several of the coastal nations that are vulnerable to the impacts of deoxygenation (Hofmann et al. 2011). Because deoxygenation may have direct economic impacts on marine resources, it warrants attention by policy-makers.

The potential consequences of ocean oxygen loss are profound, but deoxygenation does not act alone. Together, warming, acidification, and deoxygenation present a triple whammy for marine life (Gruber 2011). Warming and deoxygenation are important synergistic stressors for marine organisms because oxygen requirements vary with temperature, and temperature thresholds are often limited by oxygen availability (Portner and Knust 2007). Low oxygen waters are also characterized by low pH, meaning that marine organisms are simultaneously experiencing oxygen and pH stress (Feely et al. 2008). Meanwhile, decreases in pH may require organisms to use more energy to maintain acid-base homeostasis, however, organismal metabolism may be limited by low oxygen conditions. Due to their interacting effects, warming, acidification, and deoxygenation need to be considered together in order to understand how marine ecosystems will respond to climate change.

What Can be Done?

Since climate change is the driving cause of ocean deoxygenation, reducing carbon dioxide (CO2) emissions is the only real solution. However, certain other actions can help to ameliorate the problem especially at a local level. Lessening other anthropogenic stressors such as nutrient pollution and overfishing may improve the resilience capacity of marine communities. Adopting climate-savvy fisheries management strategies that consider the spatial and temporal extent of hypoxia and are reflective of the changing nature of the marine environment, would aid in protecting oxygen-sensitive marine resources.

- written by Natalya Gallo

# data[].attributes.attachment_link.description
Oxygen is necessary to support life on Earth. Oxygen makes up about 21% of the air we breathe and half of this oxygen is produced by phytoplankton in the ocean. All aerobic life requires oxygen to produce energy. In water, oxygen is found in a dissolved form and is much more limiting.

# data[].attributes.attachment_link.description
California State Parks, State of California

# data[].attributes.attachment_link.description
Weather is a specific event-like a rainstorm or hot day-that happens over a few hours, days or weeks. Climate is the average weather conditions in a place over 30 years or more. NASA has observed that Earth's climate is getting warmer.

# data[].attributes.attachment_link.readable_text
FROM SPACE TO GENOMICS : THE NEW FRONTIERS OF OCEAN SCIENCE Technological progress regarding spatial and in situ observation, combined with improved data processing, provide real-time access to the state of the ocean. Scientific collaboration and knowledge-sharing open new perspectives for a better understanding of the interactions between ocean, climate and biodiversity. On March 27, 2018, The Ocean and Climate...

# data[].attributes.attachment_link.description
FROM SPACE TO GENOMICS : THE NEW FRONTIERS OF OCEAN SCIENCE Technological progress regarding spatial and in situ observation, combined with improved data processing, provide real-time access to the state of the ocean. Scientific collaboration and knowledge-sharing open new perspectives for a better understanding of the interactions between ocean, climate and biodiversity.

# data[].attributes.attachment_link.title
A visual tour of the world's CO2 emissions

# data[].attributes.attachment_link.description
A new high-resolution computer model created by NASA shows carbon dioxide, the greenhouse gas driving global warming, as you've never seen it before. Subscribe to our channel! http://goo.gl/0bsAjO Vox.com is news website that helps you cut through the noise and understand what's really driving the events in the headlines.

# data[].attributes.attachment_link.description
What are fossil fuels? How were they formed? Learn how human use of non-renewable energy sources, such coal, oil, and natural gas, affect climate change.

# data[].attributes.attachment_link.title
EXPLORE ACTIVITY -- 5.7 A: FORMATION OF FOSSIL FUELS (Grade Level 5)

# data[].attributes.attachment_link.readable_text
Wind turbines and solar panels are an increasingly common sight. But why? What are the benefits of renewable energies-and how do they improve our health, environment, and economy?

This page explores the many positive impacts of clean energy, including the benefits of wind, solar, geothermal, hydroelectric, and biomass. For more information on their negative impacts-including effective solutions to avoid, minimize, or mitigate-see our page on The Environmental Impacts of Renewable Energy Technologies.

Less global warming

Human activity is overloading our atmosphere with carbon dioxide and other global warming emissions. These gases act like a blanket, trapping heat. The result is a web of significant and harmful impacts, from stronger, more frequent storms, to drought, sea level rise, and extinction.

In the United States, about 29 percent of global warming emissions come from our electricity sector. Most of those emissions come from fossil fuels like coal and natural gas [ 1, 2].

What is CO2e?

Carbon dioxide (CO2) is the most prevalent greenhouse gas, but other air pollutants-such as methane-also cause global warming. Different energy sources produce different amounts of these pollutants. To make comparisons easier, we use a carbon dioxide equivalent, or CO2e-the amount of carbon dioxide required to produce an equivalent amount of warming.

In contrast, most renewable energy sources produce little to no global warming emissions. Even when including "life cycle" emissions of clean energy (ie, the emissions from each stage of a technology's life-manufacturing, installation, operation, decommissioning), the global warming emissions associated with renewable energy are minimal [ 3].

The comparison becomes clear when you look at the numbers. Burning natural gas for electricity releases between 0.6 and 2 pounds of carbon dioxide equivalent per kilowatt-hour (CO2E/kWh); coal emits between 1.4 and 3.6 pounds of CO2E/kWh. Wind, on the other hand, is responsible for only 0.02 to 0.04 pounds of CO2E/kWh on a life-cycle basis; solar 0.07 to 0.2; geothermal 0.1 to 0.2; and hydroelectric between 0.1 and 0.5.

Renewable electricity generation from biomass can have a wide range of global warming emissions depending on the resource and whether or not it is sustainably sourced and harvested.

Increasing the supply of renewable energy would allow us to replace carbon-intensive energy sources and significantly reduce US global warming emissions.

For example, a 2009 UCS analysis found that a 25 percent by 2025 national renewable electricity standard would lower power plant CO2 emissions 277 million metric tons annually by 2025-the equivalent of the annual output from 70 typical (600 MW) new coal plants [ 4].

In addition, a ground-breaking study by the US Department of Energy's National Renewable Energy Laboratory (NREL) explored the feasibility of generating 80 percent of the country's electricity from renewable sources by 2050. They found that renewable energy could help reduce the electricity sector's emissions by approximately 81 percent [ 5].

Improved public health

The air and water pollution emitted by coal and natural gas plants is linked with breathing problems, neurological damage, heart attacks, cancer, premature death, and a host of other serious problems. The pollution affects everyone: one Harvard University study estimated the life cycle costs and public health effects of coal to be an estimated $74.6 billion every year. That's equivalent to 4.36 cents per kilowatt-hour of electricity produced-about one-third of the average electricity rate for a typical US home [ 6].

Most of these negative health impacts come from air and water pollution that clean energy technologies simply don't produce. Wind, solar, and hydroelectric systems generate electricity with no associated air pollution emissions. Geothermal and biomass systems emit some air pollutants, though total air emissions are generally much lower than those of coal- and natural gas-fired power plants.

In addition, wind and solar energy require essentially no water to operate and thus do not pollute water resources or strain supplies by competing with agriculture, drinking water, or other important water needs. In contrast, fossil fuels can have a significant impact on water resources: both coal mining and natural gas drilling can pollute sources of drinking water, and all thermal power plants, including those powered by coal, gas, and oil, withdraw and consume water for cooling.

Biomass and geothermal power plants, like coal- and natural gas-fired power plants, may require water for cooling. Hydroelectric power plants can disrupt river ecosystems both upstream and downstream from the dam. However, NREL's 80-percent-by-2050 renewable energy study, which included biomass and geothermal, found that total water consumption and withdrawal would decrease significantly in a future with high renewables [ 7].

Inexhaustible energy

Strong winds, sunny skies, abundant plant matter, heat from the earth, and fast-moving water can each provide a vast and constantly replenished supply of energy. A relatively small fraction of US electricity currently comes from these sources, but that could change: studies have repeatedly shown that renewable energy can provide a significant share of future electricity needs, even after accounting for potential constraints [ 9].

In fact, a major government-sponsored study found that clean energy could contribute somewhere between three and 80 times its 2013 levels, depending on assumptions [8]. And the previously mentioned NREL study found that renewable energy could comfortably provide up to 80 percent of US electricity by 2050.

Jobs and other economic benefits

Compared with fossil fuel technologies, which are typically mechanized and capital intensive, the renewable energy industry is more labor intensive. Solar panels need humans to install them; wind farms need technicians for maintenance.

This means that, on average, more jobs are created for each unit of electricity generated from renewable sources than from fossil fuels.

Renewable energy already supports thousands of jobs in the United States. In 2016, the wind energy industry directly employed over 100,000 full-time-equivalent employees in a variety of capacities, including manufacturing, project development, construction and turbine installation, operations and maintenance, transportation and logistics, and financial, legal, and consulting services [ 10]. More than 500 factories in the United States manufacture parts for wind turbines, and wind power project installations in 2016 alone represented $13.0 billion in investments [ 11].

Other renewable energy technologies employ even more workers. In 2016, the solar industry employed more than 260,000 people, including jobs in solar installation, manufacturing, and sales, a 25% increase over 2015 [ 12]. The hydroelectric power industry employed approximately 66,000 people in 2017 [ 13]; the geothermal industry employed 5,800 people [ 14].

Increased support for renewable energy could create even more jobs. The 2009 Union of Concerned Scientists study of a 25-percent-by-2025 renewable energy standard found that such a policy would create more than three times as many jobs (more than 200,000) as producing an equivalent amount of electricity from fossil fuels [ 15].

In contrast, the entire coal industry employed 160,000 people in 2016 [ 26].

In addition to the jobs directly created in the renewable energy industry, growth in clean energy can create positive economic "ripple" effects. For example, industries in the renewable energy supply chain will benefit, and unrelated local businesses will benefit from increased household and business incomes [ 16].

Local governments also benefit from clean energy, most often in the form of property and income taxes and other payments from renewable energy project owners. Owners of the land on which wind projects are built often receive lease payments ranging from $3,000 to $6,000 per megawatt of installed capacity, as well as payments for power line easements and road rights-of-way. They may also earn royalties based on the project's annual revenues. Farmers and rural landowners can generate new sources of supplemental income by producing feedstocks for biomass power facilities.

UCS analysis found that a 25-by-2025 national renewable electricity standard would stimulate $263.4 billion in new capital investment for renewable energy technologies, $13.5 billion in new landowner income from? biomass production and/or wind land lease payments, and $11.5 billion in new property tax revenue for local communities [ 17].

Stable energy prices

Renewable energy is providing affordable electricity across the country right now, and can help stabilize energy prices in the future.

Although renewable facilities require upfront investments to build, they can then operate at very low cost (for most clean energy technologies, the "fuel" is free). As a result, renewable energy prices can be very stable over time.

Moreover, the costs of renewable energy technologies have declined steadily, and are projected to drop even more. For example, the average price to install solar dropped more than 70 percent between 2010 and 2017 [ 20]. The cost of generating electricity from wind dropped 66 percent between 2009 and 2016 [ 21]. Costs will likely decline even further as markets mature and companies increasingly take advantage of economies of scale.

In contrast, fossil fuel prices can vary dramatically and are prone to substantial price swings. For example, there was a rapid increase in US coal prices due to rising global demand before 2008, then a rapid fall after 2008 when global demands declined [ 23]. Likewise, natural gas prices have fluctuated greatly since 2000 [ 25].

Using more renewable energy can lower the prices of and demand for natural gas and coal by increasing competition and diversifying our energy supplies. And an increased reliance on renewable energy can help protect consumers when fossil fuel prices spike.

Reliability and resilience

Wind and solar are less prone to large-scale failure because they are distributed and modular. Distributed systems are spread out over a large geographical area, so a severe weather event in one location will not cut off power to an entire region. Modular systems are composed of numerous individual wind turbines or solar arrays. Even if some of the equipment in the system is damaged, the rest can typically continue to operate.

For example, Hurricane Sandy damaged fossil fuel-dominated electric generation and distribution systems in New York and New Jersey and left millions of people without power. In contrast, renewable energy projects in the Northeast weathered Hurricane Sandy with minimal damage or disruption [ 25].

Water scarcity is another risk for non-renewable power plants. Coal, nuclear, and many natural gas plants depend on having sufficient water for cooling, which means that severe droughts and heat waves can put electricity generation at risk. Wind and solar photovoltaic systems do not require water to generate electricity and can operate reliably in conditions that may otherwise require closing a fossil fuel-powered plant. (For more information, see How it Works: Water for Electricity.)

The risk of disruptive events will also increase in the future as droughts, heat waves, more intense storms, and increasingly severe wildfires become more frequent due to global warming-increasing the need for resilient, clean technologies.
Learn more: References:
[1] Environmental Protection Agency. 2017. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2015.

[2] Energy Information Agency (EIA). 2017. How much of the U.S. carbon dioxide emissions are associated with electricity generation?

[3] Intergovernmental Panel on Climate Change (IPCC). 2011. IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation. Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp. (Chapter 9).

[4] Union of Concerned Scientists (UCS). 2009. Clean Power Green Jobs.

[5] National Renewable Energy Laboratory (NREL). 2012. Renewable Electricity Futures Study. Volume 1, pg. 210.

[6] Epstein, P.R.,J. J. Buonocore, K. Eckerle, M. Hendryx, B. M. Stout III, R. Heinberg, R. W. Clapp, B. May, N. L. Reinhart, M. M. Ahern, S. K. Doshi, and L. Glustrom. 2011. Full cost accounting for the life cycle of coal in "Ecological Economics Reviews." Ann. N.Y. Acad. Sci. 1219: 73-98.

[7] Renewable Electricity Futures Study. 2012.

[8] NREL. 2016. Estimating Renewable Energy Economic Potential in the United States: Methodology and Initial Results.

[9] Renewable Electricity Futures Study. 2012.

IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation. Prepared by Working Group III of the Intergovernmental Panel on Climate Change. 2011.

UCS. 2009. Climate 2030: A national blueprint for a clean energy economy.

[10] American Wind Energy Association (AWEA). 2017. AWEA U.S. Wind Industry Annual Market Report: Year Ending 2016. Washington, D.C.: American Wind Energy Association.

[11] Wiser, Ryan, and Mark Bolinger. 2017. 2016 Wind Technologies Market Report. U.S. Department of Energy.

[12] The Solar Foundation. 2017. National Solar Jobs Census 2016.

[13] Navigant Consulting. 2009. Job Creation Opportunities in Hydropower.

[14] Geothermal Energy Association. 2010. Green Jobs through Geothermal Energy.

[15] UCS. 2009. Clean Power Green Jobs.

[16] Environmental Protection Agency. 2010. Assessing the Multiple Benefits of Clean Energy: A Resource for States. Chapter 5.

[17] UCS. 2009. Clean Power Green Jobs.

[18] Deyette, J., and B. Freese. 2010. Burning coal, burning cash: Ranking the states that import the most coal. Cambridge, MA: Union of Concerned Scientists.

[20] SEIA. 2017. Solar Market Insight Report 2017 Q2.

[21] AWEA. 2017. AWEA U.S. Wind Industry Annual Market Report: Year Ending 2016. Washington, D.C.: American Wind Energy Association.

[22] UCS. 2009. Clean Power Green Jobs.

[23] UCS. 2011. A Risky Proposition: The financial hazards of new investments in coal plants.

[24] EIA. 2013. U.S. Natural Gas Wellhead Price.

[25] Unger, David J. 2012. Are renewables stormproof? Hurricane Sandy tests solar, wind. The Christian Science Monitor. November 19.

[26] Department of Energy. 2017 U.S. Energy and Employment Report

# data[].attributes.attachment_link.description
Wind turbines and solar panels are an increasingly common sight. But why? What are the benefits of renewable energies-and how do they improve our health, environment, and economy? This page explores the many positive impacts of clean energy, including the benefits of wind, solar, geothermal, hydroelectric, and biomass.

# data[].attributes.attachment_link.readable_text
Credit:

John Sylvester/Nature's Best Photography

The threat that climate change poses to polar bears has received a lot of attention, but they are not the only Arctic species at risk. Ice-loving seals, such as harp, hooded and ringed seals, are among the many species threatened by climate change. Recent predictions suggest that warming seawater and air will melt 20 percent or more of the Arctic's ice cover in the next 40 years-a scary statistic for the many species in the Arctic that rely on seasonal ice cover for vital activities such as breeding and eating.

Harp seals (Pagophilus groenlandicus) are a prime example of why sea ice matters. These seals give birth to pure white pups on Arctic ice floes. During their first six weeks of life, before they grow large enough to spend most of their time in the water, the pups use the ice as platforms for nursing and resting. But as ice melts more quickly, pups are forced into the water before they are ready to fend for themselves. These young pups are especially at risk for hypothermia, starvation, and being crushed by moving ice in the Arctic.

Yearlings (seals between one and two years old) are also harmed by declining sea ice because their food is found along the edges of the ice. Harp seals feed primarily on small crustaceans and fish, such as krill, capelin and sand lance, which both use the sea ice edge as shelter from their own predators and feed on algae associated with the sea ice edge.

You don't have to go to the Artic to see the effects of declining sea ice. After a summer in their northern feeding grounds, harp seals migrate south. Some adults stop to spend the winter at breeding grounds in the Gulf of St. Lawrence or along the coast of Newfoundland. However, other harp seals, mostly immature seals and adult males, may continue south. Some seals swim as far south as New England and the mid-Atlantic, where since 1991, over 3,000 sick or dead harp seals have stranded on U.S. beaches. As part of a team of four scientists from the Duke University Marine Lab, we wanted to figure out whether these strandings were related to the melting Arctic ice.

We found that most of the stranded seals were yearlings, which are particularly susceptible to stranding because they tend to be smaller, weaker, and have less experience fending for themselves. Young males stranded more frequently than young females, perhaps because of their tendency to wander further than females. This wanderlust is not well understood, but it is likely to be physically stressful, further weakening the male seals. Most importantly, we found a clear relationship between the number of young seals stranded and loss of sea ice.

The increase in stranded young seals in low-ice years does not bode well for other ice-dependent marine animals, including polar bears and several species of whales, seals, and seabirds. If ice continues to decrease across the Arctic, these species will need to adapt to the changing environment in order to survive, but we do not yet know which species are capable of adaptation and at what rate.

Genetic diversity-the amount of DNA variation within a species-can provide some indication of a species' general fitness, including their ability to bounce back from threats such as disease and changing environmental conditions. Fortunately, we found high genetic diversity in harp seals sampled in the Northeast. However, it remains to be seen whether or not harp seals will be capable of adapting at the rate necessary to respond to the already occurring rapid declines in sea ice cover.

Read the paper at PLoS ONE.

# data[].attributes.attachment_link.title
Ice-Loving Seals and the Loss of Sea Ice

# data[].attributes.attachment_link.description
The threat that climate change poses to polar bears has received a lot of attention, but they are not the only Arctic species at risk. Ice-loving seals, such as harp, hooded and ringed seals, are among the many species threatened by climate change.

# data[].attributes.attachment_link.readable_text
Antarctic: Weddell seal. Weddell seals are able to stay underwater for up to 80 minutes while they look for breathing holes in the sea ice.Many different species of seal live in both Antarctica and the Arctic, and life cycles vary considerably among species. Some species depend entirely on the presence of sea ice to survive. Many give birth and nurse their pups on the ice, and they look for food near the ice edge and under the ice. Most seals never leave the ice pack, creating open breathing holes all winter, and they make lairs under snow mounds to protect newborn pups from polar bears and from the cold air above (Krajick 2001).

Many different species of seal live in both Antarctica and the Arctic, and life cycles vary considerably among species. Some species depend entirely on the presence of sea ice to survive. Many give birth and nurse their pups on the ice, and they look for food near the ice edge and under the ice. Most seals never leave the ice pack, creating open breathing holes all winter, and they make lairs under snow mounds to protect newborn pups from polar bears and from the cold air above (Krajick 2001).

Arctic Seals

Six seal species live in the Arctic: harp, hooded, ringed, bearded, spotted, and ribbon. Although sea ice affects all these seal species, harp, ringed, and bearded seals have life cycles that are tightly linked to sea ice. Harp seals follow and live at the sea ice edge all year. In the spring, harp seals migrate southward, assembling in large groups to breed near the Newfoundland and Norwegian coasts. During late February and early March, thousands of harp seal females gather to deliver their babies on the White Sea ice (Pagophilus.org 2001).

Ringed and bearded seals often use holes in the ice to breathe, and they congregate along the edges of the ice. Ringed seals use fast ice and sometimes dense pack ice for giving birth. They require sufficient snow cover on the ice to construct birth lairs, and the sea ice must be stable enough in the spring to rear the pups. Some ringed seals in the Okhotsk Sea regularly give birth on the exposed sea ice surface (Pagophilus.Org 2001). Unlike the harp seal, the ringed seal does not migrate to open water in the winter.

Decreasing sea ice extent would reduce the habitat available to ringed seals. Early ice breakup could result in premature separation of mothers and pups, leading to higher death rates among newborn pups. In the southern Baltic Sea, from 1989 to 1995, a series of nearly ice-free winters led to very high pup mortality rates (HÃ¤rkÃ¶nen et al. 1998). If autumn and winter are fairly mild, the ice is soft and thin and disintegrates easily. As a result, newborn seal pups, which are born on the ice, do not have enough time to wean properly and may not survive. Seal pups need at least 12 days on the ice before they finish nursing (Nickerson 2002).

In 1998, ice in the western Arctic broke up three weeks earlier than usual, sending pups into the water before they had been weaned. In 2002, many seal mothers had no choice but to give birth in open water because they could not find ice, which resulted in several hundred pups drowning (Johansen, in press).

Antarctic Seals

Although only four species of seal are found in Antarctica (crabeater, Weddell, leopard, and Ross), there are many more individual seals in Antarctica than in the Arctic. This is primarily due to the crabeater seal, which far outnumbers any other species; there are more crabeater seals than all other seal species combined. Despite their name, crabeaters subsist almost entirely in krill, and so they are part of the phytoplankton-based Antarctic food chain. Like Arctic seals, crabeater seals depend on pack ice for breeding and giving birth.

Although killer whales can also pose a threat, the primary predators of crabeater seals are leopard seals. Because of their large size, leopard seals cannot move easily on sea ice, and so crabeater seals often rest on floes where they are safe from predation. Clearly, a decrease in sea ice could negatively affect crabeater seal populations by increasing predation and decreasing breeding and birthing sites.

Sea ice characteristics also affect Weddell seals, the favorite among most Antarctic visitors because of their placid nature. Weddell seals spend most of their time beneath fast ice, coming onto the sea ice surface only to rest and have their pups. Modified physiology allows Weddell seals to spend up to 80 minutes underwater, sufficient time to hunt and search for cracks in the ice that they can use as breathing holes.

# data[].attributes.attachment_link.description
Antarctic: Weddell seal. Weddell seals are able to stay underwater for up to 80 minutes while they look for breathing holes in the sea ice.Many different species of seal live in both Antarctica and the Arctic, and life cycles vary considerably among species. Some species depend entirely on the presence of sea ice to survive.

# data[].attributes.attachment_link.title
Ringed, Ribbon, Spotted, and Bearded Ice Seals | NOAA Fisheries Alaska Regional Office

# data[].attributes.attachment_link.description
Ringed Seals: On December 28, 2012, NOAA Fisheries published a final rule listing the Arctic, Okhotsk, and Baltic subspecies as threatened, and the Ladoga subspecies as endangered. Arctic ringed seals occur in U.S. waters off Alaska's coast. On March 11, 2016, the U.S.

# data[].attributes.attachment_link.readable_text
Section Overview

1. What is Dissolved Oxygen

2. Dissolved Oxygen and Aquatic Life

3. Where Does Dissolved Oxygen Come From
-Dissolved Oxygen From Photosynthesis

4. Dissolved Oxygen Saturation
-What Affects Oxygen Solubility
-How Water Can be More Than 100% Saturated

5. Typical Dissolved Oxygen Levels
-Freshwater Organisms and DO Requirements
-Saltwater Organisms and DO Requirements

6. Consequences of Unusual Dissolved Oxygen Levels
-Fish Kills
-Gas Bubble Disease
-Dead Zones

7. Dissolved Oxygen and Water Column Stratification
-Lake Stratification
-Oceanic Stratification
-Estuary Stratification

8. Dissolved Oxygen Units of Measurement
-Calculating DO from % Air Saturation

9. Dissolved Oxygen Measurement Methods

10. Dissolved Oxygen Sensor Technologies

11. Applications

What is Dissolved Oxygen?

Dissolved oxygen refers to the level of free, non-compound oxygen present in water or other liquids. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water. In limnology (the study of lakes), dissolved oxygen is an essential factor second only to water itself ¹. A dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality.

Non-compound oxygen, or free oxygen (O2), is oxygen that is not bonded to any other element. Dissolved oxygen is the presence of these free O2 molecules within water.The bonded oxygen molecule in water (H2O) is in a compound and does not count toward dissolved oxygen levels. One can imagine that free oxygen molecules dissolve in water much the way salt or sugar does when it is stirred ².

Dissolved Oxygen and Aquatic Life

Dissolved oxygen is necessary to many forms of life including fish, invertebrates, bacteria and plants. These organisms use oxygen in respiration, similar to organisms on land. Fish and crustaceans obtain oxygen for respiration through their gills, while plant life and phytoplankton require dissolved oxygen for respiration when there is no light for photosynthesis ⁴. The amount of dissolved oxygen needed varies from creature to creature. Bottom feeders, crabs, oysters and worms need minimal amounts of oxygen (1-6 mg/L), while shallow water fish need higher levels (4-15 mg/L)⁵.

Microbes such as bacteria and fungi also require dissolved oxygen. These organisms use DO to decompose organic material at the bottom of a body of water. Microbial decomposition is an important contributor to nutrient recycling. However, if there is an excess of decaying organic material (from dying algae and other organisms), in a body of water with infrequent or no turnover (also known as stratification), the oxygen at lower water levels will get used up quicker ⁶.

Where Does DO Come From?

Dissolved oxygen enters water through the air or as a plant byproduct. From the air, oxygen can slowly diffuse across the water's surface from the surrounding atmosphere, or be mixed in quickly through aeration, whether natural or man-made ⁷. The aeration of water can be caused by wind (creating waves), rapids, waterfalls, ground water discharge or other forms of running water. Man-made causes of aeration vary from an aquarium air pump to a hand-turned waterwheel to a large dam.

Dissolved oxygen is also produced as a waste product of photosynthesis from phytoplankton, algae, seaweed and other aquatic plants ⁸.

Dissolved Oxygen from Photosynthesis

While most photosynthesis takes place at the surface (by shallow water plants and algae), a large portion of the process takes place underwater (by seaweed, sub-surface algae and phytoplankton). Light can penetrate water, though the depth that it can reach varies due to dissolved solids and other light-scattering elements present in the water. Depth also affects the wavelengths available to plants, with red being absorbed quickly and blue light being visible past 100 m. In clear water, there is no longer enough light for photosynthesis to occur beyond 200 m, and aquatic plants no longer grow. In turbid water, this photic (light-penetrating) zone is often much shallower.

Regardless of wavelengths available, the cycle doesn't change ⁹. In addition to the needed light, CO2 is readily absorbed by water (it's about 200 times more soluble than oxygen) and the oxygen produced as a byproduct remains dissolved in water¹⁰. The basic reaction of aquatic photosynthesis remains:

CO2 + H2O → (CH2O) + O2

As aquatic photosynthesis is light-dependent, the dissolved oxygen produced will peak during daylight hours and decline at night ⁸.

Dissolved Oxygen Saturation

In a stable body of water with no stratification, dissolved oxygen will remain at 100% air saturation. 100% air saturation means that the water is holding as many dissolved gas molecules as it can in equilibrium. At equilibrium, the percentage of each gas in the water would be equivalent to the percentage of that gas in the atmosphere - i.e. its partial pressure ¹³. The water will slowly absorb oxygen and other gasses from the atmosphere until it reaches equilibrium at complete saturation ¹⁰. This process is sped up by wind-driven waves and other sources of aeration ³.

In deeper waters, DO can remain below 100% due to the respiration of aquatic organisms and microbial decomposition. These deeper levels of water often do not reach 100% air saturation equilibrium because they are not shallow enough to be affected by the waves and photosynthesis at the surface ³. This water is below an invisible boundary called the thermocline (the depth at which water temperature begins to decline)¹¹.

What Affects Oxygen Solubility?

Two bodies of water that are both 100% air-saturated do not necessarily have the same concentration of dissolved oxygen. The actual amount of dissolved oxygen (in mg/L) will vary depending on temperature, pressure and salinity ¹.

First, the solubility of oxygen decreases as temperature increases ¹. This means that warmer surface water requires less dissolved oxygen to reach 100% air saturation than does deeper, cooler water. For example, at sea level (1 atm or 760 mmHg) and 4°C (39°F), 100% air-saturated water would hold 10.92 mg/L of dissolved oxygen. ³ But if the temperature were raised to room temperature, 21°C (70°F), there would only be 8.68 mg/L DO at 100% air saturation ³.

Second dissolved oxygen decreases exponentially as salt levels increase ¹. That is why, at the same pressure and temperature, saltwater holds about 20% less dissolved oxygen than freshwater ³.

Third, dissolved oxygen will increase as pressure increases ¹. This is true of both atmospheric and hydrostatic pressures. Water at lower altitudes can hold more dissolved oxygen than water at higher altitudes. This relationship also explains the potential for "supersaturation" of waters below the thermocline - at greater hydrostatic pressures, water can hold more dissolved oxygen without it escaping ¹. Gas saturation decreases by 10% per meter increase in depth due to hydrostatic pressure ¹². This means that if the concentration of dissolved oxygen is at 100% air saturation at the surface, it would only be at 70% air saturation three meters below the surface.

In summary, colder, deeper fresh waters have the capability to hold higher concentrations of dissolved oxygen, but due to microbial decomposition, lack of atmospheric contact for diffusion and the absence of photosynthesis, actual DO levels are often far below 100% saturation ¹⁰. Warm, shallow saltwater reaches 100% air saturation at a lower concentration, but can often achieve levels over 100% due to photosynthesis and aeration. Shallow waters also remain closer to 100% saturation due to atmospheric contact and constant diffusion ¹⁰.

If there is a significant occurrence of photosynthesis or a rapid temperature change, the water can achieve DO levels over 100% air saturation. At these levels, the dissolved oxygen will dissipate into the surrounding water and air until it levels out at 100% ³.

How Can Water be More than 100% Saturated?

100% air saturation is the equilibrium point for gases in water. This is because gas molecules diffuse between the atmosphere and the water's surface. According to Henry's Law, the dissolved oxygen content of water is proportional to the percent of oxygen (partial pressure) in the air above it ¹³. As oxygen in the atmosphere is about 20.3%, the partial pressure of oxygen at sea level (1 atm) is 0.203 atm. Thus the amount of dissolved oxygen at 100% saturation at sea level at 20° C is 9.03 mg/L ¹⁰.

The equation shows that water will remain at 100% air saturation at equilibrium. However, there are several factors that can affect this. Aquatic respiration and decomposition lower DO concentrations, while rapid aeration and photosynthesis can contribute to supersaturation. During the process of photosynthesis, oxygen is produced as a waste product. This adds to the dissolved oxygen concentration in the water, potentially bringing it above 100% saturation ¹⁴. In addition, the equalization of water is a slow process (except in highly agitated or aerated situations). This means that dissolved oxygen levels can easily be more than 100% air saturation during the day in photosynthetically active bodies of water ¹⁴.

Supersaturation caused by rapid aeration is often seen beside hydro-power dams and large waterfalls ¹². Unlike small rapids and waves, the water flowing over a dam or waterfall traps and carries air with it, which is then plunged into the water. At greater depths and thus greater hydrostatic pressures, this entrained air is forced into solution, potentially raising saturation levels over 100% ¹².

Rapid temperature changes can also create DO readings greater than 100% ¹⁴. As water temperature rises, oxygen solubility decreases. On a cool summer night, a lake's temperature might be 60° F. At 100% air saturation, this lake's dissolved oxygen levels would be at 9.66 mg/L. When the sun rises and warms up the lake to 70° F, 100% air saturation should equate to 8.68 mg/L DO ³. But if there is no wind to move the equilibration along, the lake will still contain that initial 9.66 mg/L DO, an air saturation of 111%.

Typical Dissolved Oxygen Levels

Dissolved oxygen concentrations are constantly affected by diffusion and aeration, photosynthesis, respiration and decomposition. While water equilibrates toward 100% air saturation, dissolved oxygen levels will also fluctuate with temperature, salinity and pressure changes ³. As such, dissolved oxygen levels can range from less than 1 mg/L to more than 20 mg/L depending on how all of these factors interact. In freshwater systems such as lakes, rivers and streams, dissolved oxygen concentrations will vary by season, location and water depth.

Freshwater Fluctuations: Example 1
In the Pompton River in New Jersey, mean dissolved oxygen concentrations range from 12-13 mg/L in winter and drop to 6-9 mg/L in the summer ⁸. That same river shows daily fluctuations of up to 3 mg/L due to photosynthesis production ⁸.

Freshwater Fluctuations: Example 2
Studies at Crooked Lake in Indiana show dissolved oxygen concentrations vary by season and depth from 12 mg/L (surface, winter) to 0 mg/L (32 m depth, late summer), with full lake turnovers in spring and fall equalizing DO levels around 11 mg/L for all depths ¹.

Rivers and streams tend to stay near or slightly above 100% air saturation due to relatively large surface areas, aeration from rapids, and groundwater discharge, which means that their dissolved oxygen concentrations will depend on the water temperature ¹. While groundwater usually has low DO levels, groundwater-fed streams can hold more oxygen due to the influx of colder water and the mixing it causes ¹⁵. Standard Methods for the Examination of Water and Wastewater defines dissolved oxygen in streams as the sum of photosynthetic byproducts, respiration, re-aeration, accrual from groundwater inflow and surface runoff ¹³.

Saltwater holds less oxygen than freshwater, so oceanic DO concentrations tend to be lower than those of freshwater. In the ocean, surface water mean annual DO concentrations range from 9 mg/L near the poles down to 4 mg/L near the equator with lower DO levels at further depths. There are lower dissolved oxygen concentrations near the equator because salinity is higher ¹⁶.

Some states have Water Quality Standard Acts, requiring minimum concentrations of dissolved oxygen; in Michigan, these minimums are 7 mg/L for cold-water fisheries and 5 mg/L for warm-water fish ¹⁷; in Colorado, "Class 1 Cold Water Aquatic Life" needs 6 mg/L, and "Class 1 Warm Water Aquatic Life" requires DO levels of at least 5 mg/L ¹⁵. In order to mimic ideal environmental systems, freshwater tanks ideally need around 8 mg/L DO for optimum growth and marine tank requirements range from 6-7 mg/L DO based on the salinity level ¹⁸. In other words, dissolved oxygen should be near 100% air saturation.

Examples of Freshwater Organisms and Dissolved Oxygen Requirements

Coldwater fish like trout and salmon are most affected by low dissolved oxygen levels ¹⁹. The mean DO level for adult salmonids is 6.5 mg/L, and the minimum is 4 mg/L ¹². These fish generally attempt to avoid areas where dissolved oxygen is less than 5 mg/L and will begin to die if exposed to DO levels less than 3 mg/L for more than a couple days ¹⁹. For salmon and trout eggs, dissolved oxygen levels below 11 mg/L will delay their hatching, and below 8 mg/L will impair their growth and lower their survival rates. ¹⁹ When dissolved oxygen falls below 6 mg/L (considered normal for most other fish), the vast majority of trout and salmon eggs will die. ¹⁹

Bluegill, Largemouth Bass, White Perch, and Yellow Perch are considered warmwater fish and depend on dissolved oxygen levels above 5 mg/L ²¹. They will avoid areas where DO levels are below 3 mg/L, but generally do not begin to suffer fatalities due to oxygen depletion until levels fall below 2 mg/L ²². The mean DO levels should remain near 5.5 mg/L for optimum growth and survival ¹².

Walleye also prefer levels over 5 mg/L, though they can survive at 2 mg/L DO levels for a short time.²⁴ Muskie need levels over 3 mg/L for both adults and eggs ²⁵. Carp are hardier, and while they can enjoy dissolved oxygen levels above 5 mg/L, they easily tolerate levels below 2 mg/L and can survive at levels below 1 mg/L ²⁶.

The freshwater fish most tolerant to DO levels include fathead minnows and northern pike. Northern pike can survive at dissolved oxygen concentrations as low as 0.1 mg/L for several days, and at 1.5 mg/L for an infinite amount of time ²⁷. Fathead minnows can survive at 1 mg/L for an extended period with only minimal effects on reproduction and growth.

As for bottom-dwelling microbes, DO changes don't bother them much. If all the oxygen at their water level gets used up, bacteria will start using nitrate to decompose organic matter, a process known as denitrification. If all of the nitrogen is spent, they will begin reducing sulfate ¹⁷. If organic matter accumulates faster than it decomposes, sediment at the bottom of a lake simply becomes enriched by the organic material. ²⁸.

Examples of Saltwater Organisms and Dissolved Oxygen Requirements

Saltwater fish and organisms have a higher tolerance for low dissolved oxygen concentrations as saltwater has a lower 100% air saturation than freshwater. In general, dissolved oxygen levels are about 20% less in seawater than in freshwater ³.

This does not mean that saltwater fish can live without dissolved oxygen completely. Striped bass, white perch and American shad need DO levels over 5 mg/L to grow and thrive ⁵. The red hake is also extremely sensitive to dissolved oxygen levels, abandoning its preferred habitat near the seafloor if concentrations fall below 4.2 mg/L ²⁹.

The dissolved oxygen requirements of open-ocean and deep-ocean fish are a bit harder to track, but there have been some studies in the area. Billfish swim in areas with a minimum of 3.5 mg/L DO, while marlins and sailfish will dive to depths with DO concentrations of 1.5 mg/L ³⁰. Likewise, white sharks are also limited in dive depths due to dissolved oxygen levels (above 1.5 mg/L), though many other sharks have been found in areas of low DO ³³. Tracked swordfish show a preference for shallow water during the day, basking in oxygenated water (7.7 mg/L) after diving to depths with concentrations around 2.5 mg/L ³⁴. Albacore tuna live in mid-ocean levels, and require a minimum of 2.5 mg/L ³⁵, while halibut can maintain a minimum DO tolerance threshold of 1 mg/L ³⁶.

Many tropical saltwater fish, including clown fish, angel fish and groupers require higher levels of DO, such as those surrounding coral reefs. Coral reefs are found in the euphotic zone (where light penetrates the water - usually not deeper than 70 m). Higher dissolved oxygen concentrations are generally found around coral reefs due to photosynthesis and aeration from eddies and breaking waves ³⁷. These DO levels can fluctuate from 4-15 mg/L, though they usually remain around 5-8 mg/L, cycling between day photosynthesis production and night plant respiration ³⁸. In terms of air saturation, this means that dissolved oxygen near coral reefs can easily range from 40-200% ³⁹.

Crustaceans such as crabs and lobsters are benthic (bottom-dwelling) organisms, but still require minimum levels of dissolved oxygen. Depending on the species, minimum DO requirements can range from 4 mg/L to 1 mg/L ¹³. Despite being bottom dwellers, mussels, oysters and clams also require a minimum of 1-2 mg/L of dissolved oxygen ²⁹, which is why they are found in shallower, coastal waters that receive oxygen from the atmosphere and photosynthetic sources.

Consequences of Unusual DO Levels

If dissolved oxygen concentrations drop below a certain level, fish mortality rates will rise. Sensitive freshwater fish like salmon can't even reproduce at levels below 6 mg/L ¹⁹. In the ocean, coastal fish begin to avoid areas where DO is below 3.7 mg/L, with specific species abandoning an area completely when levels fall below 3.5 mg/L ²⁹. Below 2.0 mg/L, invertebrates also leave and below 1 mg/L even benthic organisms show reduced growth and survival rates ²⁹.

Fish kill / Winterkill

A fishkill occurs when a large number of fish in an area of water die off. It can be species-based or a water-wide mortality. Fish kills can occur for a number of reasons, but low dissolved oxygen is often a factor. A winterkill is a fish kill caused by prolonged reduction in dissolved oxygen due to ice or snow cover on a lake or pond ²⁰.

When a body of water is overproductive, the oxygen in the water may get used up faster than it can be replenished. This occurs when a body of water is overstocked with organisms or if there is a large algal bloom die-off.

Fish kills are more common in eutrophic lakes: lakes with high concentrations of nutrients (particularly phosphorus and nitrogen) ⁴¹. High levels of nutrients fuel algae blooms, which can initially boost dissolved oxygen levels. But more algae means more plant respiration, drawing on DO, and when the algae die, bacterial decomposition spikes, using up most or all of the dissolved oxygen available. This creates an anoxic, or oxygen-depleted, environment where fish and other organisms cannot survive. Such nutrient levels can occur naturally, but are more often caused by pollution from fertilizer runoff or poorly treated wastewater ⁴¹.

Winterkills occur when respiration from fish, plants and other organisms is greater than the oxygen production by photosynthesis ¹. They occur when the water is covered by ice, and so cannot receive oxygen by diffusion from the atmosphere. If the ice is then covered by snow, photosynthesis also cannot occur, and the algae will depend entirely on respiration or die off. In these situations, fish, plants and decomposition are all using up the dissolved oxygen, and it cannot be replenished, resulting in a winter fish kill. The shallower the water, and the more productive (high levels of organisms) the water, the greater the likelihood of a winterkill ²⁰.

Gas Bubble Disease

Just as low dissolved oxygen can cause problems, so too can high concentrations. Supersaturated water can cause gas bubble disease in fish and invertebrates ¹². Significant death rates occur when dissolved oxygen remains above 115%-120% air saturation for a period of time. Total mortality occurs in young salmon and trout in under three days at 120% dissolved oxygen saturation ¹². Invertebrates, while also affected by gas bubble disease, can usually tolerate higher levels of supersaturation than fish ¹².

Extended periods of supersaturation can occur in highly aerated waters, often near hydropower dams and waterfalls, or due to excessive photosynthetic activity. Algae blooms can cause air saturations of over 100% due to large amounts of oxygen as a photosynthetic byproduct. This is often coupled with higher water temperatures, which also affects saturation. ¹² At higher temperatures, water becomes 100% saturated at lower concentrations, so higher dissolved oxygen concentrations mean even higher air saturation levels.

Dead Zones

A dead zone is an area of water with little to no dissolved oxygen present. They are so named because aquatic organisms cannot survive there. Dead zones often occur near heavy human populations, such as estuaries and coastal areas off the Gulf of Mexico, the North Sea, the Baltic Sea, and the East China Sea. They can occur in large lakes and rivers as well, but are more well known in the oceanic context.

These zones are usually a result of a fertilizer-fueled algae and phytoplankton growth boom. When the algae and phytoplankton die, the microbes at the seafloor use up the oxygen decomposing the organic matter ³¹. These anoxic conditions are usually stratified, occurring only in the lower layers of the water. While some fish and other organisms can escape, shellfish, young fish and eggs usually die ³².

Naturally occurring hypoxic (low oxygen) conditions are not considered dead zones. The local aquatic life (including benthic organisms) have adjusted to the recurring low-oxygen conditions, so the adverse effects of a dead zone (mass fish kills, sudden disappearance of aquatic organisms, and growth/development problems in fish and invertebrates) do not occur ³¹.

Such naturally occurring zones frequently occur in deep lake basins and lower ocean levels due to water column stratification.

Dissolved Oxygen and Water Column Stratification

Stratification separates a body of water into layers. This layering can be based on temperature or dissolved substances (namely salt and oxygen) with both factors often playing a role. The stratification of water has been commonly studied in lakes, though it also occurs in the ocean. It can also occur in rivers if pools are deep enough and in estuaries where there is a significant division between freshwater and saltwater sources.

Lake Stratification

The uppermost layer of a lake, known as the epilimnion, is exposed to solar radiation and contact with the atmosphere, keeping it warmer. The depth of the epilimnion is dependent on the temperature exchange, usually determined by water clarity and depth of mixing (usually initiated by wind) ¹¹. Within this upper layer, algae and phytoplankton engage in photosynthesis. Between the contact with the air, potential for aeration and the byproducts of photosynthesis, dissolved oxygen in the epilimnion remains near 100% saturation. The exact levels of DO vary depending on the temperature of the water, the amount of photosynthesis occurring and the quantity of dissolved oxygen used for respiration by aquatic life.

Below the epilimnion is the metalimnion, a transitional layer that fluctuates in thickness and temperature. The boundary between the epilimnion and metalimnion is called the thermocline - the point at which water temperature begins to steadily drop off ¹¹. Here, two different outcomes can occur. If light can penetrate beyond the thermocline and photosynthesis occurs in this strata, the metalimnion can achieve an oxygen maximum ¹¹. This means that the dissolved oxygen level will be higher in the metalimnion than in the epilimnion. But in eutrophic or nutrient-rich lakes, the respiration of organisms can deplete dissolved oxygen levels, creating a metalimnetic oxygen minimum ⁴².

The next layer is the hypolimnion. If the hypolimnion is deep enough to never mix with the upper layers, it is known as the monimolimnion. The hypolimnion is separated from the upper layers by the chemocline or halocline. These clines mark the boundary between oxic and anoxic water and salinity gradients, respectively. ¹¹. While lab conditions would conclude that at colder temperatures and higher pressures water can hold more dissolved oxygen, this is not always the result. In the hypolimnion, bacteria and fungi use dissolved oxygen to decompose organic material ⁶. This organic material comes from dead algae and other organisms that sink to the bottom. The dissolved oxygen used in decomposition is not replaced - there is no atmospheric contact, aeration or photosynthesis to restore DO levels in the hypolimnion ¹¹. Thus the process of decomposition "uses up" all of the oxygen within this layer.

If the lake in question is a holomictic "mixing" lake, all the layers mix at least once per year (usually spring and fall) when lake strata temperatures align. This turnover redistributes dissolved oxygen throughout all the layers and the process begins again.

Ocean Stratification

Stratification in the ocean is both horizontal and vertical. The littoral, or coastal area is most affected by estuaries and other inflow sources.⁴⁴ It tends to be shallow and tidal with fluctuating dissolved oxygen levels. The sublittoral, also known as the neritic or demersal zone, is considered a coastal zone as well. In this zone, dissolved oxygen concentrations may vary but they do not fluctuate as much as they do in the littoral zone.

This is the zone where many coral reefs grow, and DO levels remain near 100% air saturation due to eddies, breaking waves and photosynthesis ⁴⁵. This zone is also where most oceanic benthic (bottom-dwelling) organisms exist. Oceanic benthic fish do not live at the greatest depths of the ocean. They dwell at the seafloor near to coasts and oceanic shelves while remaining in the upper levels of the ocean.

Beyond the demersal zone are the bathyal, abyssal and hadal plains, which are fairly similar in terms of consistently low DO.

In the open ocean, there are five major vertical strata: epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadalpelagic ⁴⁴. The exact definitions and depths are subjective, but the following information is generally agreed upon. The epipelagic is also known as the surface layer or photic zone (where light penetrates). This is the layer with the highest levels of dissolved oxygen due to wave action and photosynthesis. The epipelagic generally reaches to 200 m and is bordered by a collection of clines.

These clines can overlap or exist at separate depths. Much like in a lake, the thermocline divides oceanic strata by temperature. The halocline divides by salinity levels and the pycnocline divides strata by density ¹⁶. Each of these clines can affect the amount of dissolved oxygen the ocean strata can hold.

The mesopelagic, meaning "twilight" zone, stretches from 200-1000 m. Depending on water clarity, some light may filter through, but there is not enough for photosynthesis to occur ⁴⁴. Within this strata, the oxygen minimum zone (OMZ) can occur. The OMZ develops because organisms use the oxygen for respiration, but it is too deep to be replenished by photosynthetic oxygen byproducts or aeration from waves. This zone tends to exist around a depth of 500 m ⁴⁵. The mesopelagic zone is bordered by chemoclines (clines based on chemistry levels, e.g. oxygen and salinity) on both sides, reflecting different dissolved oxygen and salinity levels between the strata.

Below the mesopelagic is the aphotic zone(s). These strata have lower dissolved oxygen levels than the surface water because photosynthesis does not occur but can have higher levels than the OMZ because less respiration occurs.

The bathypelagic, "midnight" zone exists between 1000-4000 m, and many creatures can still live here. The bottom layer of the ocean is the abyssopelagic, which exists below 4000 m. The hadopelagic is the name for the zone of deep ocean trenches that open below the abyssal plain, such as the Mariana Trench ⁴⁴.

Estuary Stratification

Estuary stratifications are based on salinity distributions. Because saltwater holds less dissolved oxygen than freshwater, this can affect aquatic organism distribution. The stronger the river flow, the higher the oxygen concentrations. This stratification can be horizontal, with DO levels dropping from inland to open ocean, or vertical, with the fresh, oxygenated river water floating over the low DO seawater ⁴⁶. When the stratification is clearly defined, a pycnocline divides the fresher water from the salt water, contributing to separate dissolved oxygen concentrations in each strata.

Dissolved Oxygen Units and Reporting

Dissolved oxygen is usually reported in milligrams per liter (mg/L) or as a percent of air saturation. However, some studies will report DO in parts per million (ppm) or in micromoles (umol). 1 mg/L is equal to 1 ppm. The relationship between mg/L and % air saturation has been discussed above, and varies with temperature, pressure and salinity of the water. One micromole of oxygen is equal to 0.022391 milligrams, and this unit is commonly used in oceanic studies ⁴⁷. Thus 100 umol/L O2 is equal to 2.2 mg/L O2.

Calculating DO from % Air Saturation

To calculate dissolved oxygen concentrations from air saturation, it is necessary to know the temperature and salinity of the sample. Barometric pressure has already been accounted for as the partial pressure of oxygen contributes to the percent air saturation ⁷. Salinity and temperature can then be used in Henry's Law to calculate what the DO concentration would be at 100% air saturation ¹⁰. However, it is easier to use an oxygen solubility chart. These charts show the dissolved oxygen concentration at 100% air saturation at varying temperatures, and salinities. This value can then be multiplied by the measured percent air saturation to calculate the dissolved oxygen concentration 7.
O2 mg/L = (Measured % DO)*(DO value from chart at temperature and salinity)
Example:
70% DO measured
35 ppt salinity
15°C

.70 * 8.135 = 5.69 mg/L DO

Cite this work:
Fondriest Environmental, Inc. "Dissolved Oxygen." Fundamentals of Environmental Measurements. 19 Nov. 2013. Web. < http://www.fondriest.com/environmental-measurements/parameters/water-quality/dissolved-oxygen/ >.

Additional Resources:

# data[].attributes.attachment_link.title
Dissolved Oxygen - Environmental Measurement Systems

# data[].attributes.attachment_link.description
Section Overview What is Dissolved Oxygen Dissolved Oxygen and Aquatic Life Where Does Dissolved Oxygen Come From -Dissolved Oxygen From Photosynthesis Dissolved Oxygen Saturation -What Affects Oxygen Solubility -How Water Can be More Than 100% Saturated Typical Dissolved Oxygen Levels -Freshwater Organisms and DO Requirements -Saltwater Organisms and DO Requirements

# data[].attributes.attachment_link.keywords[]
Boats and boating--Equipment and supplies

# data[].attributes.body
Scientific literacy involves understanding global climate change & what people can do about it

# data[].attributes.attachment_link.readable_text
Practice Brief 12 -- Topics: InformalEd Instruction Background Teaching Climate

Scientific literacy involves understanding global climate change & what people can do about it

Teachers should engage students in the analysis of multiple strands of authentic climate change data, including historic, current, and predictive datasets and models.

District staff & PD providers should provide sustained PD opportunities that engage teachers in learning to teach about climate change from an interdisciplinary science perspective.

School leaders and state-level policymakers should provide resources that help teachers focus instruction on contemporary climate change.

What is the Issue?

The complexities of climate change and its interdisciplinary nature can make it feel like a daunting teaching task. However, this complexity reflects the systemic nature of many of today's environmental challenges-making it an ideal platform for implementing practice-based instruction focused on contemporary science in the classroom. The science and engineering practices of modeling, analyzing data, argumentation, and designing solutions should be a central focus of any climate change curriculum.

Authors:

BY VERONICA MCGOWAN - MAY 2015

Reflection Questions

What particular aspects of climate change could be relevant to practice-based instruction in your classroom?

Consider the claim from the NRC Framework: "It is clear not only that human activities play a major role in climate change but also that impacts of climate change...have begun to influence human activities." How can this site help you engage students and community members with understanding this idea?

Things to Consider

All young people are entitled to develop a scientific understanding of climate change and to know how engineering solutions can allow us to mitigate impacts, adapt practices, and build resilient systems.

Climate change is an interdisciplinary science topic. Aspects of the topic can be taught in different science classes without losing the big picture ideas of systems thinking, managing uncertainty, and building arguments based on multiple lines of data. Here are examples of climate subsystem topics across different subjects:
Biology: Students can study how shifts in climate can disrupt ecosystems (LS2.C) and have and will continue to affect biological life cycles, called phenology. Phenological shifts and phenological mismatches are already being observed among plants and wildlife.
Chemistry: Students can study how ocean acidification results from the absorption of excess CO2 from the atmosphere in seawater and can have large-scale impacts on marine life. They can also study how climate changes impacts agriculture by reducing arable land.
Physics: Changes in atmospheric gas composition are already impacting the flow of energy and matter around Earth. Students can investigate how these shifts impact absorption and release of solar radiation and impacts of warming temperatures on ocean currents.
Earth Sciences: Geographic Information Systems (GIS) and computer models are major tools for modeling the impacts of climate change globally. Students can analyze existing models and create their own (e.g., in Google Maps). It is important for students to understand the carbon cycling process (see ESS2.E for details).

When arguing about climate change in the classroom, remind students that scientific arguments are supported by multiple lines of observed and modeled data, and not political opinions or untested assumptions. Allow students to engage with the social controversy by having them evaluate media and political arguments in light of the evidence given. Students can explore if speakers are using scientific evidence to support their claims.

Attending to Equity

Global climate change has been impacting many communities in less to more severe ways for many years. It is a social imperative to respond to climate change within local communities and in general while recognizing that energy production is a major driver.

Youth are likely to bring a range of perspectives to the study of climate change. Remember that shifting views around socially controversial issues can require deep identity shifts in students and should not be a required part of climate change learning.

Recommended Actions You Can Take

ALSO SEE STEM TEACHING TOOLS

STEM Teaching Tools content copyright 2014-19 UW Institute for Science + Math Education. All rights reserved.
This site is primarily funded by the National Science Foundation (NSF) through the Research + Practice Collaboratory (Award #1238253). Opinions expressed are not those of any funding agency.

Work is licensed under a Creative Commons Attribution-ShareAlike 4.0 Unported License. Others may adapt with attribution. Funded by the National Science Foundation (NSF). Opinions expressed are not those of any funding agency.

# data[].attributes.attachment_link.title
Scientific literacy involves understanding global climate change & what people can do about it : StemTeachingTools (en-US)

# data[].attributes.attachment_link.description
Practice Brief 12 -- Topics: InformalEd Instruction Background Teaching Climate Teachers should engage students in the analysis of multiple strands of authentic climate change data, including historic, current, and predictive datasets and models. District staff & PD providers should provide sustained PD opportunities that engage teachers in learning to teach about climate change from an interdisciplinary science perspective.

# data[].attributes.attachment_link.title
Weather Versus Climate Change | Cosmos: A Spacetime Odyssey

# data[].attributes.attachment_link.readable_text
Subject Area: Earth Sciences/Science

Prerequisite Knowledge: The understanding that living beings are made out of carbon

Goal: To provide a believable and visual representation of how heat and pressure can modify the structure of organic matter.

Time Required: 2 days (second day 2 days after first)
Materials Needed (per set-up):

1. 1 large paper towel

2. 3 slices of bread of at least 2 different colours (white, brown, rye)

3. Gummy candy fish/animals

4. 1-2 heavy books

5. 1 Clear drinking straw

Opening (PDF worksheet attached at the end of page):
Did you know that coal, crude oil (from which gasoline and diesel and even petroleum jelly are made) and natural gas are all fossil fuels?

Can you think of some ways in which we use fossil fuels today? Let's try to name a few of them together.

Fossils are old right? Fossil fuels are even older than the fossils you have perhaps seen in museums. Watch the video to see how fossil fuels were formed.

[ Fossil Fuel Formation]
Do you remember how many years ago the prehistoric animals and plants that make up the crude oil we use today lived on Earth?
It's hard to believe that just sand and mud and water and the pressure from the weight of these can turn plants and animals into oil and gas, isn't it? But they can...only we're missing one key ingredient - TIME.

Layers of sand and mud and water over lots and lots of time - like more than two hundred million years - is what it takes to turn dead plants and animals into fossil fuels. 100-200 million years ago is a very, very long time ago. Tyrannosaurus Rex lived and killed smaller dinosaurs on Earth just 65-70 million years ago. So most of the fossil fuels we use today are much older than that.

I'd like to show you how to make fossil fuels, but we don't really have 200 million years to spare. Luckily, we can do what is called a simulation. We can use other stuff to stand in for the plants and animals and microorgansims at the bottom of the ocean and for the layers of sand and mud that got dumped on top. It's take us a few days, however, but not nearly as long as it would take to get natural gas.

We're going to use gummy candy as our plants and animals and different coloured bread to be our different layers of mud and soil and sand. Take a look at the picture to get an idea of what the whole thing will look like.

1. Here's what we're going to do:The bottom of the ocean is white, so let's put a slice of white bread on top on one side of the paper towel. Great, now we have our ocean floor. Remember we are going to fold the paper towel over the last piece of bread in the end.

2. Place one gummy fish on top of your ocean floor (white bread slice).

3. Now place the slice of rye bread on top. Your slices of bread should be lined up with each other and your gummy fish should be hidden from sight. The rye bread stands in for the sediments deposited by the ocean. Remember that this actually takes a very long time to happen.

4. Now scatter your remaining gummy fish over the rye bread followed by the final slice of bread. This represents the natural processes that have taken place over millions of years, as more sand and sediments have been deposited by wind and ocean currents.

5. Now fold the paper towel over the entire thing to cover your bread fossil.

Are we done? Not quite. What is missing to fossilize your fish? Can you guess?

PRESSURE. We need to add pressure. To do that, place 1-2 heavy textbooks or dictionaries on top to simulate the natural process of pressure from sediment deposits and the weight of the ocean.

Leave your model for 2 days. Each day represents 100 million years of natural time.

After one or two days, observe the bread fossil. Push a clear straw straight down into the bread and "extract" a core sample. Observe the layers through the straw.

Try to separate the layers of bread. Why do you think the layers are difficult to separate? Now try to extract the gummy fish. Can you identify the fish's impression in the bread (fossil)? How about the bread around the fossil? What do you think that will look like after the fossil has completely melted?

The residue left by the gummy fish on the bread layer just above it after the gummy fish has completely melted represents oil deposits left by the dead ocean plants and animals. Over millions of years the pressure from the deposits and water liquefies the remains and turns it into fossil fuels.

Attached Worksheet:
Gummy Bread Fossils

# data[].attributes.attachment_link.title
Gummy Fossils: Simulating the Formation of Fossil Fuels

# data[].attributes.attachment_link.description
Subject Area: Earth Sciences/Science Prerequisite Knowledge: The understanding that living beings are made out of carbon Goal: To provide a believable and visual representation of how heat and pressure can modify the structure of organic matter.

# data[].attributes.attachment_link.readable_text
Quick Look

Grade Level: 4 (3-5)

Time Required: 45 minutes

Lesson Dependency: None

Subject Areas: Earth and Space, Physical Science, Science and Technology

NGSS Performance Expectations:

Summary Students investigate sources of fossil fuels, particularly oil. Through two associated activities, they work with a model of the Earth to learn how engineers and scientists look for oil by taking core samples, and they explore and analyze oil consumption and production in the U.S. and around the world.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Finding fossil fuels below the Earth's surface is a challenge for geological and petroleum engineers. Much investigation is done before drilling expensive wells: They examine core samples, look for natural fractures in the reservoir rock, and investigate the size and porosity of the reservoir and how fast oil droplets move through the pores. Engineers also design special machines and tools for extracting and transporting oil, and complex refining processes to convert the crude oil into many forms of usable energy.

Learning Objectives

After this lesson, students should be able to:

Describe the origin of fossil fuels.

Explain the important role of engineering in gathering and finding oil.

Describe how people use oil in their everyday lives.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Patterns can be used as evidence to support an explanation. Science assumes consistent patterns in natural systems.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Cause and effect relationships are routinely identified and used to explain change. Knowledge of relevant scientific concepts and research findings is important in engineering. Over time, people's needs and wants change, as do their demands for new and improved technologies.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

A system can be described in terms of its components and their interactions. Science findings are limited to questions that can be answered with empirical evidence.

Analyze and interpret data to generate evidence about the prehistoric environment (Grade 4) More Details
View aligned curriculum

Do you agree with this alignment?

Create and evaluate models of the flow of nonliving components or resources through an ecosystem (Grade 4) More Details
View aligned curriculum

Do you agree with this alignment?

Use multiple resources - including print, electronic, and human - to locate information about different sources of renewable and nonrenewable energy (Grade 4) More Details
View aligned curriculum

Do you agree with this alignment?

Suggest an alignment not listed above

Introduction/Motivation

What is as precious as gold? Oil! Have you ever wondered where oil comes from, or what its use is? Well, the U.S. gets about 37% of its energy from oil, a fossil fuel that is also referred to as petroleum, which comes from sedimentary rocks under the Earth's surface. It takes millions of years to create oil. The process started way before the times of dinosaurs, but some estimates project that humans will use all the oil that exists in 40 to 60 years. Americans have been drilling for oil since about 1859, when the first oil well was constructed (see Figure 1).

How do oil companies extract (pull out) these tiny droplets away from the rock located thousands of feet underground? How does this oil move through the dense rock and into wells that take it to the surface? How do the tiny droplets combine into the billions of gallons of oil that the U.S. and the rest of the world use each day? Where should engineers drill oil wells to ensure that the most oil is contacted? How should machinery be built and used to get oil? So many questions exist about oil. Fortunately, scientists and engineers use their science and math skills to find answers and solutions to these questions.

First, to harvest oil, we must find it. But, how do you know where is it if you cannot see under the ground? Geological and petroleum engineers drill holes in the Earth to get core samples of the underground layers. If oil is found in the core sample, then the chances are good that more oil is present in the region surrounding the core. Next, the oil must be extracted and transported to a location where it can be used. Refer to the associated activity Model Earth Core Samples: What's Down There? to have students act as engineers in harvesting and analyzing their own core samples. Unfortunately, many of the steps involved in getting oil to our homes and vehicles have the potential to generate pollution. Pulling oil up to the surface of the Earth can pollute the ground, moving oil to other locations sometimes results in oil spills, and burning oil to get energy for automobiles or to get electricity at power plants can generate air pollution.

Despite the potential for pollution, oil provides energy for most of the U.S. Most cars run on gasoline, which is made from oil, and many houses are heated by oil. Engineers need to know about oil reservoirs before they begin the process of drilling wells, which is very costly. Incorrect predictions can be costly errors for oil companies. They need to know about the size and number of pores in reservoir rock. They need to know how fast oil droplets move through these pores. They need to know where the natural fractures are in reservoirs so that they know where to drill wells. Finding the answers involves research that is a mix of fluid mechanics, thermodynamics, applied mathematics and geology, which are all engineering areas of study. Engineers develop the machines and tools used for all steps for the extraction, transportation and burning of oil for energy. Students can expand their knowledge of these engineering practices with the literacy activity A Closer Look at Oil and Energy Consumption by analyzing oil consumption and production data in the U.S. and around the world.

Lesson Background and Concepts for Teachers

Sedimentary Rocks

Fossil fuels are energy-rich substances that have formed from the Earth's long-buried plants and microorganisms. Crude oil, one common fossil fuel, is formed in sedimentary rocks. Sedimentary rocks are rock layers formed from sediments, such as sand and organic matter that are transported, deposited and cemented together over time. Sedimentary rocks typically have visible layers of different kinds of sediment (see Figure 2).

The sediment is always deposited in horizontal layers, one on top of the other. Therefore, sedimentary rocks exhibit horizontal layers initially, and the layers closest to the bottom, or found deeper under the Earth's surface, are the oldest. Over time, however, the Earth's natural and dynamic processes, such as erosion and plate tectonics, can alter the rocks. Plate tectonics causes rocks to fold and fault, as seen in Figure 3.

How Fossil Fuels are Formed

Millions of years ago, in certain parts of the world, when thriving marine communities with lots of different organisms died, they became organic matter (sediments) on the ocean floor. Over time, more sediment was deposited on top, and both layers solidified into sedimentary rock. A sediment layer with a lot of organic matter has the potential to become oil, provided a couple of other things happen. Usually, microorganisms consume the organic matter in rock layers; however, if the rocks are located in a low-oxygen environment, different microorganisms-called anaerobic organisms-turn the organic matter into methane. Methane, also called natural gas, is made of hydrogen and carbon that can itself be used for energy or it can be turned into oil. Methane becomes oil if it is created deep below the Earth's surface and trapped there by an impermeable rock that it cannot pass through. Impermeable rocks, such as granite that trap methane and oil under the ground are called cap rocks. At locations where cap rocks are faulted, or folded, large oil deposits can be found (see Figure 4).

Oil can also found in reservoir rocks, which are permeable rocks in which methane gas became trapped as it migrated up and turned into oil (see Figure 5).

Processing and Finding Oil

First, to harvest oil, we must find it even though it is deep underground where we cannot see. Geological and petroleum engineers drill holes in the Earth to get core samples of the underground layers. If oil is found in the core, then the chances are good that a lot more oil exists in the area surrounding the core. Engineers set up equipment to drill in the exact area that their tests show contain a lot of oil. Then, the oil is extracted, usually by the use of oil wells that pump the oil up to the surface. Extracting oil and using oil can be potentially harmful to the environment. Sometimes when the oil is brought to the surface it contains sediments that cannot be used for energy. If these sediments are not disposed of carefully, they can cause pollution. Once extracted, the oil is transported to where it will be refined and used. During transport, oil has the potentially to cause more pollution. For example, sometimes tankers full of oil run aground and cause oil spills or steadily leak into the ocean. Finally, refining and burning oil contributes to air pollution-and that is in addition to vehicles burning refined oil products, such as gasoline, for energy. Despite the potential for pollution, oil provides essential energy for most of the U.S. Most of our nation's cars run on gasoline, which is made from oil, and many houses are heated by oil, not to mention the enormous amount of plastic products made from crude oil. Because of the anticipated decline in oil supplies and contributions to pollution, engineers are continually searching for more efficient ways to power automobiles and heat houses that use less oil.

Associated Activities

Lesson Closure

What is oil used for? (Possible answers: Oil is refined into many products for many purposes. Some oil is burned to create energy to run automobiles, heat houses, or for oil-burning lamps. Some oil is refined into lubricants used for maintenance of moveable parts such as motors, door hinges and swings. Some oil is used in to create the uncountable number and types of plastic materials that we use every day.)

Where does oil come from? (Answer: Oil is a fossil fuel found underground that was created from plants and animals that were alive millions of years ago.)

In what ways can oil contribute to pollution? (Possible answers: The side-effects of air, land and water pollution from burning it in vehicles, industry and factories, and during the extraction of and transportation of oil from the Earth.)
Can you think of any ways to help reduce the pollution caused by the drilling and transport of oil? Do you have any ideas of ways to conserve oil so we do not run out of it?

Vocabulary/Definitions

cap rock: A very hard, impermeable rock that traps methane and oil under the ground.

core: A long, thin sample of rock taken from deep below the Earth's surface.

fossil fuel: Energy-rich substances that have formed from the Earth's long-buried plants and microorganisms. Three commonly-used fossil fuels: coal, oil (petroleum) and natural gas.

fracture: A tiny crack in rock layers.

pore: An open space within rock material.

reservoir rock: A rock formation with special kinds of porous rocks that contains oil droplets.

sedimentary rock: Layers of rock that were formed by accumulation of rock fragments, shell fragments, plant material, mud and sands, which were transported to their present locations by water, air, wind or ice.

Assessment

Pre-Lesson Assessment

Brainstorming: Have students generate a number of possible ideas about the following question. Remind students that no idea or suggestion is "silly." All ideas should be respectfully heard. Ask the students:

What are some of the many uses for oil? (Possible answers: Car fuel, lamp fuel, heaters, to make a hinges and parts work smoothly, to make plastics.)

Post-Introduction Assessment

Question/Answer: Ask questions and have students raise their hands to answer. Discuss their answers as a class.

Where does oil come from? (Answer: It is found in between the layers of sedimentary rocks under the Earth's surface.)

How fast do we expect humans to use all the oil? (Answer: It is estimated that people will use all the oil left in 40 to 60 years.)

What are two types of engineers who work to find and gather oil? (Answer: Petroleum and geological engineers.)

How do engineers get oil from the ground? (Answer: They drill for it after they have verified its existence through core samples obtained from areas that are predicted to contain oil.)

After oil is found, what else must be done with it before it can be used in our homes and cars? (Answer: It must be extracted, refined or modified for specific purposes, and transported.)

Can oil cause pollution? (Answer: Yes. Pulling oil up to the surface of the Earth can pollute the ground, moving oil to another location can leak and cause oil spills on land and water, and burning oil to get energy in cars or at energy plants pollutes the air.)

What types of things do engineers need to know before drilling for oil? (Answer: They must know the size of oil reservoirs and how oil moves through the reservoirs.)

Lesson Summary Assessment

Numbered Heads: Divide the class into teams of three to five students each. Have students on each team number off so each has a different number. Ask the students a question (give them a time frame for solving it, if desired). Have the members of each team work together to formulate an answer. Everyone on the team must know the answer. Call a number at random. Students with that number raise their hands to answer the question. If not all students with that number raise their hands, give the teams a bit more time. Pick a student to answer. Continue until you get the correct answer.

How is oil formed? (Answer: From plant and animal microorganisms, or sediments.)

When was oil made? (Answer: Millions of years ago.)

Where is oil found? (Answer: Deep below the Earth's surface, in reservoir rocks.)

For additional questions, see the Post-Introduction Assessment section.

Lesson Extension Activities

Simulate taking a core sample by using transparent plastic drinking straws and filled or layered cupcakes; see http://www.coaleducation.org/lessons/wim/4.htm.

Have students research the world's top oil producers and consumers and then make a bar graph of their data . A good source for data can be found at https://www.eia.gov/beta/international/index.cfm?topL=con

References

Keller, Edward A. Environmental Geology, 7th Edition: New York, NY: Prentice Hall, 1996.

U.S. Energy Information Agency. "U.S. Energy Facts Explained." Last updated May 7, 2020. Accessed on October 30, 2020. https://www.eia.gov/energyexplained/us-energy-facts/.

Copyright © 2004 by Regents of the University of Colorado

Contributors Jessica Todd; Melissa Straten; Malinda Schaefer Zarske; Janet Yowell

Supporting Program Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: November 20, 2020

# data[].attributes.attachment_link.description
Students investigate sources of fossil fuels, particularly oil. Through two associated activities, they work with a model of the Earth to learn how engineers and scientists look for oil by taking core samples, and they explore and analyze oil consumption and production in the U.S. and around the world.

# data[].attributes.attachment_link.title
The Anthropocene: Human Impact on the Environment

# data[].attributes.attachment_link.description
Human activities are reshaping our planet in profound ways. The changes that have occurred in the last 50 to 200 years have led scientists to propose a new geologic epoch, called the Anthropocene. Use this interactive to see how human population growth, air pollution, agriculture, mining, water use, and other human activities have impacted the environment and the mark they will leave in the fossil record.

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.readable_text
Our Trajectory

Earth Will Continue to Warm and the Effects Will Be Profound

The potential future effects of global climate change include more frequent wildfires, longer periods of drought in some regions, and an increase in the wind intensity and rainfall from tropical cyclones. Credit: left - Mike McMillan/USFS, center - Tomas Castelazo / Wikimedia Commons / CC BY-SA 4.0, right - NASA.

Global climate change is not a future problem. Changes to Earth's climate driven by increased human emissions of heat-trapping greenhouse gases are already having widespread effects on the environment: glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, plant and animal geographic ranges are shifting, and plants and trees are blooming sooner.

Effects that scientists had long predicted would result from global climate change are now occurring, such as sea ice loss, accelerated sea level rise, and longer, more intense heat waves.

" The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation and adaptation actions, and projected adverse impacts and related losses and damages escalate with every increment of global warming."

- Intergovernmental Panel on Climate Change

Some changes (such as droughts, wildfires, and extreme rainfall) are happening faster than scientists previously assessed. In fact, according to the Intergovernmental Panel on Climate Change (IPCC) - the United Nations body established to assess the science related to climate change - modern humans have never before seen the observed changes in our global climate, and some of these changes are irreversible over the next hundreds to thousands of years.

Scientists have high confidence that global temperatures will continue to rise for many decades, mainly due to greenhouse gases produced by human activities.

A Degree of Difference

So, the Earth's average temperature has increased about 2 degrees Fahrenheit during the 20th century. What's the big deal?

Read more

The IPCC's Sixth Assessment report, published in 2021, found that human emissions of heat-trapping gases have already warmed the climate by nearly 2 degrees Fahrenheit (1.1 degrees Celsius) since 1850-1900. The global average temperature is expected to reach or exceed 1.5 degrees C (about 3 degrees F) within the next few decades. These changes will affect all regions of Earth.

What's the difference between climate change and global warming?

"Global warming" refers to the long-term warming of the planet. "Climate change" encompasses global warming, but refers to the broader range of changes that are happening to our planet, including rising sea levels; shrinking mountain glaciers; accelerating ice melt in Greenland, Antarctica and the Arctic; and shifts in flower/plant blooming times.

detailed answer

The severity of effects caused by climate change will depend on the path of future human activities. More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects across our planet. However, those future effects depend on the total amount of carbon dioxide we emit. So, if we can reduce emissions, we may avoid some of the worst effects.

" The scientific evidence is unequivocal: climate change is a threat to human wellbeing and the health of the planet. Any further delay in concerted global action will miss the brief, rapidly closing window to secure a liveable future." ²

- Intergovernmental Panel on Climate Change

Future Effects in the U.S.

U.S. Regional Effects

U.S. Regional Effects

Climate change is bringing different types of challenges to each region of the country. Some of the current and future impacts are summarized below. These findings are from the Third and Fourth National Climate Assessment Reports, released by the U.S. Global Change Research Program.

Is it too late to prevent climate change?

Humans have caused major climate changes to happen already, and we have set in motion more changes still. However, if we stopped emitting greenhouse gases today, the rise in global temperatures would begin to flatten within a few years. Temperatures would then plateau but remain well-elevated for many, many centuries.

detailed answer

Northeast. Heat waves, heavy downpours, and sea level rise pose increasing challenges to many aspects of life in the Northeast. Infrastructure, agriculture, fisheries, and ecosystems will be increasingly compromised. Farmers can explore new crop options, but these adaptations are not cost- or risk-free. Moreover, adaptive capacity, which varies throughout the region, could be overwhelmed by a changing climate. Many states and cities are beginning to incorporate climate change into their planning.

Northwest. Changes in the timing of peak flows in rivers and streams are reducing water supplies and worsening competing demands for water. Sea level rise, erosion, flooding, risks to infrastructure, and increasing ocean acidity pose major threats. Increasing wildfire incidence and severity, heat waves, insect outbreaks, and tree diseases are causing widespread forest die-off.

Southeast. Sea level rise poses widespread and continuing threats to the region's economy and environment. Extreme heat will affect health, energy, agriculture, and more. Decreased water availability will have economic and environmental impacts.

Midwest. Extreme heat, heavy downpours, and flooding will affect infrastructure, health, agriculture, forestry, transportation, air and water quality, and more. Climate change will also worsen a range of risks to the Great Lakes.

Southwest. Climate change has caused increased heat, drought, and insect outbreaks. In turn, these changes have made wildfires more numerous and severe. The warming climate has also caused a decline in water supplies, reduced agricultural yields, and triggered heat-related health impacts in cities. In coastal areas, flooding and erosion are additional concerns.

References
References
Header image shows cracked mud stretches across sections of the Panamint Valley. Credit: NPS/Kurt Moses; A degree of concern thermometer image credit: Pixabay/geralt

# data[].attributes.attachment_link.keywords[]
intergovernmental panel on climate change

# data[].attributes.attachment_link.description
Vital Signs of the Planet: Global Climate Change and Global Warming. Long-term effects of global climate change in the United States.

# data[].attributes.attachment_link.readable_text
Simply put, without greenhouse gases, or the greenhouse effect, Earth would be a frozen planet, incapable of sustaining life as we know it. There would be no plants, no trees, no animals, just frozen ice and stone.

We need greenhouse gases to capture and hold heat from the sun. Not enough greenhouse gases and we are in an ice age. Too much greenhouse gases and we are in the age of the dinosaurs, or worse. Greenhouse gases are essential sustain the planet as we now know it.

The dominant natural greenhouse gases are H ₂0 (water), CO ₂ (carbon dioxide), CH ₄ (methane), and Nitrous oxide (N ₂O). There are also industrial CFC's (Chlorofluorocarbons). H ₂0, CO ₂, CH ₄, and N ₂ O are all naturally present in the the atmosphere. Chiefly, these gases and the ones that keep us warm enough to live relatively comfortably here on Earth. This is the "natural" greenhouse effect.

The natural forces imposed on our climate system, such as the external forcing of the sun and the Milankovitch cycles, and the internal responses of the climate system control the amount of warmth we enjoy.

The main concern today is that, by the burning of fossil-fuels and other activities, humans increasing the abundance of greenhouse gases in the atmosphere, contributing to an enhanced greenhouse effect. This enhanced greenhouse effect is not natural.

Greenhouse Gases

The National Academy of Sciences, National Research Council, Board on Atmospheric Science and Climate Present 'Climate Change: Lines of Evidence - Greenhouse Gases'

Understanding what it means to add greenhouse gases:

If you need to go somewhere in your car, you need to add gas. Your measure of distance is MPG (Miles per Gallon) or KPL (Kilometers per Liter). The same applies to temperature in our atmosphere. The atmosphere is the tank. The more gas you add, the more distance you can travel. The difference is that in this case the distance is temperature, not miles.

Links

Greenhouse Gas Emissions:

Commentary from Andrew Lacis re. Lacis et al 2010

From NOAA/NCDC

What is the greenhouse effect, and is it affecting our climate?

The greenhouse effect is unquestionably real and helps to regulate the temperature of our planet. It is essential for life on Earth and is one of Earth's natural processes. It is the result of heat absorption by certain gases in the atmosphere (called greenhouse gases because they effectively 'trap' heat in the lower atmosphere) and re-radiation downward of some of that heat. Water vapor is the most abundant greenhouse gas, followed by carbon dioxide and other trace gases. Without a natural greenhouse effect, the temperature of the Earth would be about zero degrees F (-18°C) instead of its present 57°F (14°C). So, the concern is not with the fact that we have a greenhouse effect, but whether human activities are leading to an enhancement of the greenhouse effect by the emission of greenhouse gases through fossil fuel combustion and deforestation.

Source: http://www.ncdc.noaa.gov/oa/climate/globalwarming.html

The Greenhouse Effect (GHE)

The greenhouse effect is the process, or mechanism, by which greenhouse gases interfere with the direct radiation of heat energy leaving the surface of the planet. In other words GHG's can get in the way of heat escaping, and thus prevent some of the heat from escaping quickly, or easily. When heat energy hits a greenhouse gas molecule it can re-radiate in any number of directions. Some energy radiates back down and some at angles to interact with other molecules.

Eventually, heat energy makes it back out to space. The amount of greenhouse gases in the atmosphere combined with other factors determine the radiative balance, and/or temperature at which relative thermal equilibrium for a planet occurs based on these factors.

How do we know CO2 is a greenhouse gas?

CO2 absorbs infrared heat

What are the major contributors to the greenhouse effect?

Estimating precisely what the contributions are to the effect is complicated by many factors. Spectral overlap, altitude, changing coverage that must be calculated based on averages. However, while getting precise numbers is difficult approximate numbers are beginning to come into focus in a more reliable way.

Gavin Schmidt et al. and Andy Lacis et al., have both had papers published in 2010 that seem to have corralled the effects into general areas with reasonable attribution. Here is what it generally breaks down to:

H₂0 (water) = around 50%

Clouds = around 25%

Non-condensing greenhouse gases 25%

CO₂ (carbon dioxide) = around 20%

All other absorbers - around 5%

Major GHG's (Greenhouse Gases)

Human & Global Impacts

High GWP's (Global Warming Potential) Gases

Greenhouse Gas Concentration

Atmospheric Lifetime

Real Climate:

# data[].attributes.attachment_link.description
Greenhouse Gases (GHG's) are the various gases that block outgoing long-wave infrared from easily leaving our atmosphere. The Greenhouse Effect (GHE) is the physical mechanism of this blocking mechanism in our atmosphere that influence how much heat we retain within the atmosphere.

# data[].attributes.attachment_link.readable_text
At the ends of the Earth, life thrives despite extreme conditions. In the and Southern Oceans, organisms have evolved adaptations to cope with year-round cold and six months of darkness. But the tough critters living in these harsh climates belie the delicate balance that holds the ecosystem together-a balance that human activities are disrupting in alarming ways.

Among the biggest threats to the poles is rapid climate change. Atmospheric carbon dioxide has been rising for more than a century, with hefty contributions from the fossil fuels used to power our homes, businesses, and cars. The increasingly dense blanket of greenhouse gases is trapping heat and taking its toll on the planet, especially at the poles. Global temperatures have increased since the 1800s with models predicting their continued rise, and sea ice has been decreasing in extent and thickness. By 2040, sea ice may disappear altogether during summer months.

The warming of polar oceans has powerful implications for organisms living there-and for us. Polar sea ice helps regulate Earth's climate. White ice reflects more of the Sun's energy back into space than does dark water. Without sea ice, Earth would absorb more solar radiation-and our climate would be even warmer.

Many animals also depend directly on sea ice. Polar bears, for instance, hunt seals from the ice and gain most of their weight in winter. But with ice declining and breaking up earlier, bears have less time to hunt. Because their habitat is melting, the bears were listed as a threatened species under the Endangered Species Act in May of 2008. Pacific walruses, which usually plow a large area of the ocean floor while looking for clams and other prey, have started congregating near the shore and on land because the sea ice is beyond their reach. Ringed seals, ivory gulls, and ice algae are just some of the other species that rely on the ice to survive.

(Capt. B. Christman, NOAA)

In polar waters, tiny swimming snails called pteropods will feel the changes in another way. In addition to warming, the ocean is becoming more acidic as it absorbs more carbon dioxide from the air. Scientists predict that during this century, parts of the Southern Ocean will be so acidic that the shells of pteropods and other organisms will begin dissolving. Since they are an essential food source for larger animals such as herring, cod, and, and baleen whales, the problems pteropods face could disrupt the entire ecosystem. Their plight also spells trouble for corals and other marine animals that build their shells or skeletons from calcium.

Other species, such as caribou, are changing their migration patterns and ranges as seasons and weather patterns shift. For people who live near the poles, like the Inuvialuit people of Sachs Harbour, Canada, weather and hunting grounds are becoming more unpredictable. Knowledge of the environment that has served generations is being defied by a changing climate. Many northern communities have also observed coastal erosion and watched the permafrost-ground that is frozen most of the year-melting and buckling under their homes and roads. While not common, some communities like Kivalina and Shishmaref, both in Alaska, are planning to entirely relocate, with costs in the hundreds of millions of dollars.

# data[].attributes.attachment_link.description
At the ends of the Earth, life thrives despite extreme conditions. In the and Southern Oceans, organisms have evolved adaptations to cope with year-round cold and six months of darkness. But the tough critters living in these harsh climates belie the delicate balance that holds the ecosystem together-a balance that human activities are disrupting in alarming ways.

# data[].attributes.headline
Why the poles warm faster then the rest of the Earth

# data[].attributes.subject
Why the poles warm faster then the rest of the Earth

# data[].attributes.attachment_link.description
The Earth as seen from the Moon by the Lunar Reconnaissance Orbiter, this is a mosaic of images snapped on 12 June 2010 during a calibration sequence. AP: Arabian Peninsula; CS: Caspian Sea; H: Himalayan Mountains; L: Lena River; I: Indian Ocean; A: Australia; J: Japan; P: Pacific Ocean; large yellow arrow indicates approximate position of the North Pole.

# data[].attributes.body
Melting sea ice

# data[].attributes.attachment_link.readable_text
This is the last of three dispatches from a New York Times reporting trip to Antarctica.

From the air, the Ross Ice Shelf looks like a vast white plain extending to the horizon. The monochromatic landscape is relieved only occasionally by rocks poking through, or by deep crevasses in the ice itself.

Only at its edge does the ice shelf become something more dramatic: a spectacular sheer cliff rising 100 feet above the ocean and extending 900 feet below the surface. From that cliff edge, icebergs occasionally calve away, completing a thousand-year journey of the ice from land to sea.

Scientists are racing to understand what is happening to the Ross Ice Shelf - and the rest of Antarctica - as the planet warms around it. They are trying to map the thickness of the ice and the shape of the sea floor beneath it in an effort to gauge how vulnerable the shelf may be to collapse, and how soon that could happen.

Scientists are also trying to measure the role of human-caused climate change in weakening some parts of the West Antarctic ice sheet, and to fathom how damaging the seas around the continent might prove to be as they warm over time.

The answers carry profound implications for humanity. In the scientists' worst-case computer simulations, continued global warming will cause the Ross Ice Shelf to weaken and collapse starting as early as the middle of this century.

Right now, the shelf works like a giant bottle-stopper that slows down ice trying to flow from the land into the sea. If it collapses, the ice could flow into the ocean more rapidly, an effect that has already happened on a much smaller scale in other areas of Antarctica.

The most vulnerable parts of the West Antarctic ice sheet could raise the sea level by 10 to 15 feet, inundating many of the world's coastal cities, though most scientists think that would take well over a century, or perhaps longer. They are worried about a possible rise of as much as six feet by the end of this century.

Whether these alarming forecasts ultimately prove right depends in part on the shape of the sea floor beneath the ice shelf, and in particular on whether it has deep channels that can funnel warming ocean water under the ice shelf and attack the West Antarctic ice sheet from below. A different undersea topography - high ridges of rock, for example - may keep warmer water out, stabilizing the ice sheet, possibly for hundreds of years.

"We're hoping to figure out how warm water can get to the edge of the ice sheet," said Robin E. Bell, head of the Columbia University laboratory that sent a team to survey the Ross Ice Shelf late last year. "What are the sort of hidden roads it can go on?"

As they flew back and forth across the vast white landscape in December, the Columbia scientists used some of the world's most sophisticated geophysical instruments to see into and beneath the ice. As the hours-long flights wore on, the scientists took turns napping, knitting or eating cold pizza, but at all times, somebody kept close watch on the instruments.

Kirsty J. Tinto, the scientist leading the field team, loved watching as the measurements stripped away the illusion that the ice was just a flat, boring pancake.

"You take a slice through it and you can see a thousand years of history, a hundred million years of history," she said.

The Ross Ice Shelf appears stable now, so the Columbia project will function somewhat like a doctor's baseline X-ray - a starting point for comparison if the ice starts to deteriorate.

Satellite evidence suggests that this is already happening in other parts of West Antarctica, and many scientists believe that relatively warm ocean water is the culprit. "It's kind of a blowtorch on the underside of the ice shelf," said Robert A. Bindschadler, a retired NASA climate scientist.

But the story is not straightforward, and the warmer water attacking the ice has not been linked to global warming - at least not directly. The winds around the continent seem to be strengthening, stirring the ocean and bringing up a layer of warmer water that has most likely been there for centuries.

Are those stronger winds tied to human-caused global warming? Some scientists think so, but others say the case is unproven. "We're not sure because we don't have enough data, for long enough, to separate signal from noise," said Eric J. Steig, a scientist at the University of Washington who has studied temperature trends in Antarctica.

Though the role of global warming is unclear now, it is likely to be a factor in the relatively near future. Many experts think warmer air temperatures could start to weaken the ice of West Antarctica from above, even as warmer ocean water attacks it from below.

The warmer water seems to be doing the most damage to a series of glaciers that flow into a region of West Antarctica called the Amundsen Sea. Satellites have identified the most rapid loss of ice there, raising a critical question: Has an unstoppable collapse of the ice sheet already begun?

The Amundsen Sea region is one of the remotest parts of the continent, far from American and British research bases. Working together, the two countries are planning to devote tens of millions of dollars to getting better measurements there, having decided that it is imperative to begin answering questions about the region's potential collapse.

For instance, scientists need to know a lot more about the ground beneath the glaciers there. Is it slick mud that may allow the ice to flow much faster, or hard rock that may slow down the ice even in a warmer world?

"What we need to know is really the details of what is occurring where the ice, ocean and land all come together," said Ted A. Scambos, a University of Colorado scientist who is helping to plan the joint research effort.

Unraveling the answers, and gaining a better understanding of how Antarctica's ice has waxed and waned in the past, may offer a rough guide to the changes that human-caused global warming could wreak in the future.

Already, scientists know enough to be concerned. About 120,000 years ago, before the last ice age, the planet went through a natural warm period, with temperatures similar to those expected in coming decades.

The sea level was 20 to 30 feet higher than it is today, implying that the ice sheets in both Greenland and Antarctica must have partly disintegrated, a warning of what could occur in the relatively near future if the heating of the planet continues unchecked.

But some research suggests that a catastrophe might not yet be inevitable. In a study last year, Robert M. DeConto of the University of Massachusetts, Amherst, and David Pollard of Pennsylvania State University used their computer model to predict what would happen if emissions were reduced sharply over the next few decades, in line with international climate goals.

Under the most ambitious scenarios, they found a strong likelihood that Antarctica would remain fairly stable.

"There's still a chance that all hell will break loose," Dr. DeConto said. "But the model is suggesting there's a way to reduce the risk of a big sea-level rise from Antarctica."

In the immersive video below, we fly past a six-mile iceberg, a tiny fragment of the Ross Ice Shelf.

# data[].attributes.attachment_link.title
Miles of Ice Collapsing Into the Sea (Published 2017)

# data[].attributes.attachment_link.description
This is the last of three dispatches from a New York Times reporting trip to Antarctica. From the air, the Ross Ice Shelf looks like a vast white plain extending to the horizon. The monochromatic landscape is relieved only occasionally by rocks poking through, or by deep crevasses in the ice itself.

# data[].attributes.body
Analyze and interpret data

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.readable_text
PASADENA, Calif. -- Ocean waters melting the undersides of Antarctic ice shelves are responsible for most of the continent's ice shelf mass loss, a new study by NASA and university researchers has found.

Scientists have studied the rates of basal melt, or the melting of the ice shelves from underneath, of individual ice shelves, the floating extensions of glaciers that empty into the sea. But this is the first comprehensive survey of all Antarctic ice shelves. The study found basal melt accounted for 55 percent of all Antarctic ice shelf mass loss from 2003 to 2008, an amount much higher than previously thought.

Antarctica holds about 60 percent of the planet's fresh water locked into its massive ice sheet. Ice shelves buttress the glaciers behind them, modulating the speed at which these rivers of ice flow into the ocean. Determining how ice shelves melt will help scientists improve projections of how the Antarctic ice sheet will respond to a warming ocean and contribute to sea level rise. It also will improve global models of ocean circulation by providing a better estimate of the amount of fresh water ice shelf melting adds to Antarctic coastal waters.

The study uses reconstructions of ice accumulation, satellite and aircraft readings of ice thickness, and changes in elevation and ice velocity to determine how fast ice shelves melt and compare the mass lost with the amount released by the calving, or splitting, of icebergs.

"The traditional view on Antarctic mass loss is it is almost entirely controlled by iceberg calving," said Eric Rignot of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the University of California, Irvine. Rignot is lead author of the study to be published in the June 14 issue of the journal Science. "Our study shows melting from below by the ocean waters is larger, and this should change our perspective on the evolution of the ice sheet in a warming climate."

Ice shelves grow through a combination of land ice flowing to the sea and snow accumulating on their surface. To determine how much ice and snowfall enters a specific ice shelf and how much makes it to an iceberg, where it may split off, the research team used a regional climate model for snow accumulation and combined the results with ice velocity data from satellites, ice shelf thickness measurements from NASA's Operation IceBridge -- a continuing aerial survey of Earth's poles -- and a new map of Antarctica's bedrock. Using this information, Rignot and colleagues were able to deduce whether the ice shelf was losing mass through basal melting or gaining it through the basal freezing of seawater.

In some places, basal melt exceeds iceberg calving. In other places, the opposite is true. But in total, Antarctic ice shelves lost 2,921 trillion pounds (1,325 trillion kilograms) of ice per year in 2003 to 2008 through basal melt, while iceberg formation accounted for 2,400 trillion pounds (1,089 trillion kilograms) of mass loss each year.

Basal melt can have a greater impact on ocean circulation than glacier calving. Icebergs slowly release melt water as they drift away from the continent. But strong melting near deep grounding lines, where glaciers lose their grip on the seafloor and start floating as ice shelves, discharges large quantities of fresher, lighter water near the Antarctic coastline. This lower-density water does not mix and sink as readily as colder, saltier water, and may be changing the rate of bottom water renewal.

"Changes in basal melting are helping to change the properties of Antarctic bottom water, which is one component of the ocean's overturning circulation," said author Stan Jacobs, an oceanographer at Columbia University's Lamont-Doherty Earth Observatory in Palisades, N.Y. "In some areas it also impacts ecosystems by driving coastal upwelling, which brings up micronutrients like iron that fuel persistent plankton blooms in the summer."

The study found basal melting is distributed unevenly around the continent. The three giant ice shelves of Ross, Filchner and Ronne, which make up two-thirds of the total Antarctic ice shelf area, accounted for only 15 percent of basal melting. Meanwhile, fewer than a dozen small ice shelves floating on "warm" waters (seawater only a few degrees above the freezing point) produced half of the total melt water during the same period. The scientists detected a similar high rate of basal melting under six small ice shelves along East Antarctica, a region not as well known because of a scarcity of measurements.

The researchers also compared the rates at which the ice shelves are shedding ice to the speed at which the continent itself is losing mass and found that, on average, ice shelves lost mass twice as fast as the Antarctic ice sheet did during the study period.

"Ice shelf melt doesn't necessarily mean an ice shelf is decaying; it can be compensated by the ice flow from the continent," Rignot said. "But in a number of places around Antarctica, ice shelves are melting too fast, and a consequence of that is glaciers and the entire continent are changing as well."

Imagery related to this release is online at: http://www.nasa.gov/topics/earth/features/earth20130613.html.

# data[].attributes.attachment_link.title
Warming ocean causing most Antarctic ice shelf mass loss

# data[].attributes.attachment_link.description
PASADENA, Calif. -- Ocean waters melting the undersides of Antarctic ice shelves are responsible for most of the continent's ice shelf mass loss, a new study by NASA and university researchers has found. Scientists have studied the rates of basal melt, or the melting of the ice shelves from underneath, of individual ice shelves, the floating extensions of glaciers that empty into the sea.

# data[].attributes.headline
Dependence on Fossil Fuels in the Future

# data[].attributes.subject
Dependence on Fossil Fuels in the Future

# data[].attributes.attachment_link.title
World's Heavy Dependence on Fossil Fuels Projected to Continue - Eos

# data[].attributes.attachment_link.description
The report forecasts a 2.8% annual increase in renewable energy through 2040, making it the world's fastest growing source of energy for electricity generation.

# data[].attributes.attachment_link.readable_text
The Globe is Warming

In 2013, the Intergovernmental Panel on Climate Change (IPCC) concluded in its authoritative fifth assessment report that "Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased". They also stated that "Human influence on the climate system is clear." How did they reach those sobering conclusions?

Scientists from NASA and other research institutions around the world have been routinely collecting temperature data from a wide number of locations all over the planet. Their records of Earth's average temperature go back to the 1880s, the earliest year for which reliable instrumental records were available worldwide. The National Climatic Data Center (NCDC), which is part of the National Oceanic and Atmospheric Administration (NOAA), has maintained global average monthly and annual records of combined land and ocean surface temperatures for more than 130 years. These data show that temperatures have climbed to more than 1.8°F (1°C) above pre-industrial levels as of 2015, and the long-term global upward trend is clear and unambiguous (Figure 1)

The 2013 Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) stated that "each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850". Data also shows that, globally, the last decade has been the warmest ever recorded - 2015 was the warmest year on record according to NASA and NOAA, and 2016 is on track to beat 2015.

Adding to the evidence of direct temperature measurements, studies by independent teams of researchers indicate that the planet is undergoing one of the largest climate changes in Earth's history, and also one of the fastest in the past 65 million years. Not only that, the current warming is projected to occur at a rate 10 times faster than any change over that period.

But how do we know Earth's temperature before 1880?

To understand climate trends from the past, before reliable measurement methods existed, climate experts rely on biological or physical archives - known as "proxies" - that preserve past temperature. Tree rings, coral skeletons, and glacial ice cores (Figure 3) are proxies for annual temperature records, while boreholes (holes drilled deep into Earth's crust) can show temperature shifts over longer periods of time.

The way scientists measure and interpret various proxies depends on the information each proxy provides. For example, to obtain temperature records from tree rings, scientists drill cores into several trees that are growing in a region. They identify site-specific factors that influence tree growth such as temperature, precipitation, altitude, and tree age, and then compare these factors against the width or density of the tree rings over the lifetime of the tree. Once researchers are confident about how local tree growth correlates to air temperature, they then seek out older trees in the region that are preserved (perhaps in a local swamp or lake). By matching rings from trees that partially overlap life spans, scientists can construct a continuous climate record over thousands of years.

Ice cores have bands of light and dark areas with traces of various substances, which can be analyzed as to composition and age, yielding important information about the environmental conditions throughout time. Antarctic ice core records vividly illustrate that atmospheric carbon dioxide (CO2) levels today are higher than levels recorded over the past 800,000 years (Figure 4).

Atmospheric CO2 levels have risen 30 percent in the last 150 years, with half of that rise occurring only in the last three decades. It is a well-established scientific fact that CO2 (and other gases emitted from industrial and agricultural sources) traps heat in the atmosphere, so it is no surprise that we are now witnessing a dramatic increase in temperature.

Reconstructions of past climates help us build accurate projections of how future climates will be affected by global warming

Much as the Air Force builds computer programs to simulate flight under different conditions, climate scientists build computer programs to help simulate global climate. These computer programs, called General Circulation Models (GCMs), use various assumptions about physical, chemical, and biological processes that occur within Earth's atmosphere and oceans and on its land surfaces. To ensure accuracy, each model is checked to see if it generates results that correctly reproduce the past and current climate. Once accuracy is established, the computer program can then be used to explore the likely future climate if, for example, we double the atmospheric concentration of carbon dioxide.

Earth's climate in the past has been warmer and colder than it is now (Figure 5). Over the past million years, shifts in orbital cycles influenced the amount of sunlight falling on the northern hemisphere and played a major role in the waxing and waning of ice ages. Whenever atmospheric carbon dioxide increased naturally (either as a direct cause or as an amplifier, see this study), global surface temperature increased further. This held true even when local temperatures in the northern hemisphere and southern hemisphere might be out of phase due to factors including ocean circulation. Past climate evidence informs just how powerful carbon dioxide is. All else being equal, increases in atmospheric carbon dioxide lead to warmer global average surface temperatures. That is a proven relationship known since at least 1861 and confirmed throughout the years.

This is also true of the current warming trend--an increase in carbon dioxide is leading to an increase in temperatures. However, in this current warming episode, the increase in CO2 is largely due to human emissions from the burning of oil, coal, and gas ( IPCC Fifth Assessment Report).

The "hockey stick" graph and its significance

The "hockey stick" graph, created by a group of climate researchers in the late 1990s, reflects average Northern Hemisphere temperature changes over the past several centuries. It was the first comprehensive study combining data from many different archives of temperature including tree rings, ice cores, and coral reefs.

It demonstrated that Northern Hemisphere temperatures rose sharply during the late 20th century, in marked contrast to the relatively small temperature fluctuations during the previous six centuries. The graph got its name because its shape resembles a hockey stick, with the blade end representing the sharp temperature rise over recent years.

Listen to climate scientist Michael Mann talk about his early climate research on the Got Science? podcast:

As is typical of the scientific process, independent teams of researchers have worked to reproduce the results of the "hockey stick" by using their own approaches and even by using slightly different data. Despite small differences, they still yield the same essential conclusion: the past 10- to 20-year period was likely the warmest of the past millennium.

The hockey stick graph is a high-profile example among literally thousands of pieces of evidence that have contributed to the present scientific consensus on the human influence on global warming. We are observing real changes due to higher temperatures. Here are some examples from the AR5:

Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.

The rate of sea level rise since the mid-19th century has been larger than the rate during the previous two millennia.

Carbon dioxide concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.

Surface temperature is only one indicator of climate change.

Glaciers are melting. Sea levels and ocean heat content are rising (Figure 7). Patterns of rainfall and snow, droughts and storms, and lake and sea ice are changing. Plant and animal distributions and interactions are shifting and changing, with potential severe effects on crop pests and food supplies.

These shifts are well documented and are largely attributed to human-caused global warming, because scientists can positively identify the " human fingerprints " associated with these changing patterns.

Compared with natural factors that influence climate (including solar variation and volcanic eruptions), human activities - primarily burning fossil fuels and deforestation - have been a major contributor to climate change over the last 50 years. Burning coal, oil and gas and destroying forests overloads the atmosphere with excess carbon dioxide, adding to heat-trapping gases that already are present in the atmosphere. Combined, these gases act like a blanket covering the earth. The human contribution to this effect is unmistakable: the part of the atmosphere where excess carbon dioxide accumulates has expanded and warmed dramatically in recent years precisely during the period when emissions from human activity have increased.

The "Long" and "Short" of Temperature Trends

When one hears the words "global warming," the image that comes to mind is one of a globe where temperatures are going up constantly, like the water in a kettle on the burner of a stove that steadily rises in temperature. But when it comes to climate the process is not quite the same.

While global temperatures have been going up overall, the rate of warming varies. As a result, some years are warmer than others. That is because there are factors, like air and ocean circulation patterns, that affect both the rate and the intensity of the global warming. For example, every few years an ocean cycle appears in the Pacific ocean either as an El Niño and La Niña with global temperature and regional precipitation pattern changes.

Imagine that you add a few external factors to that imaginary warming kettle (a fan or air conditioning vent blowing directly at the stove; adding more water (hot or cold) to the kettle; a bucket of ice cubes sitting by its side; etc.) and what we have is a heating system that is affected by those other factors - but the water will still eventually boil unless the burner is turned off or turned down significantly.

The "burner" in global warming is represented by the heat-trapping emissions released to the atmosphere from the burning of coal, oil, and natural gas - and since that burner has not (yet!) been reduced significantly (enough for the heating to slow down and prevent boiling), what we have is a warming planet. Relatively short-term natural phenomena that cause global temperatures to fluctuate are also occurring throughout the seasons, which we experience as a result of the Earth's tilted axis as it revolves around the sun.

Short-term effects and external factors make it possible to have "cooler" periods in regions even as the general trend of warming continues. For example, during late 2007 and early 2008, the tropical Pacific Ocean was much cooler than normal due to a strong La Niña episode that kept temperatures across much of the globe lower than usual. Nevertheless, both years were still among the warmest years on record and would have been even hotter without this short-term cooling effect. Conversely, in 2015, a very strong El Niño episode, which made the tropical Pacific Ocean warmer than normal, combined with human-induced global warming to make that year the hottest on record to date (Nov 2016). And needless to say, winters continue to be colder than summers, even though some are more or less cold.

Oscillations between cooler and warmer periods are therefore expected, and do not change the long-term trend of warming shown by the data. Focusing on the relatively short time periods where the rate of warming is slower in order to claim that global warming is not happening is a misleading way to use statistics, yet one that has been the focus of attention. If one starts to measure a warming trend from a much warmer year, the rate of warming is bound to be different from the long term trend, simply due to the starting point (Figure 8).

Climate, Weather, and the United States

Climate is a good indicator of what to expect in general, such as cold days in February in New England. Weather, on the other hand, is what we actually experience, like a blustery, snowy day with temperatures in the low 20s. In other words, climate describes phenomena observed over long time periods, such as decades and centuries, while weather is observed over short time periods, such as days and weeks.

The Earth's average temperature is continuing to rise, regardless of the fact that some parts of the United States can still experience atypically cold winters (see this page for more on that). Cold winters do not disprove the fact that temperatures are rising. Plus, the US land area covers only about two percent of the Earth's surface, which means that even when much of the United States is cold, most of the rest of the world may be warmer.

Temperatures in the United States keep breaking records. In 2015 most of the country experienced temperatures above average or much above average, and unless global emissions are reduced significantly, the trend is likely to continue.

It's Not Too Late

The choices we make today can help determine what our climate will be like. Putting a limit on heat-trapping emissions and encouraging the use of healthier, cleaner energy technologies, such as solar and wind power, would help us to avoid the worst potential consequences of global warming.

# data[].attributes.attachment_link.title
Here's How we Know That the Earth's Temperature is Rising

# data[].attributes.attachment_link.description
In 2013, the Intergovernmental Panel on Climate Change (IPCC) concluded that "The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased". They also stated that "Human influence on the climate system is clear."

# data[].attributes.body
look at change since 1979

# data[].attributes.attachment_link.keywords[]
national aeronautics and space administration

# data[].attributes.attachment_link.title
Global Ice Viewer - Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.description
Ice, which covers 10 percent of Earth's surface, is disappearing rapidly. Select a topic below to see how climate change has affected glaciers, sea ice, and continental ice sheets worldwide.

# data[].attributes.attachment_link.readable_text
mong the many strange mantras repeated by climate change deniers is the claim that even in an overheated, climate-altered planet, animals and plants will still survive by adapting to global warming. Corals, trees, birds, mammals and butterflies are already changing to the routine reality of global warming, it is argued.

Certainly, countless species have adapted to past climate fluctuations. However, their rate of change turns out to be painfully slow, according to a study by Professor John Wiens of the University of Arizona. Using data from 540 living species, including amphibians, reptiles, birds and mammals, Wiens and colleagues compared their rates of evolution with the rates of climate change projected for the end of this century. The results, published online in the journal Ecology Letters, show that most land animals will not be able to evolve quickly enough to adapt to the dramatically warmer climate expected by 2100. Many species face extinction, as a result.

"We found that, on average, species usually adapt to different climatic conditions at a rate of only by about 1C per million years," Wiens explained. "But if global temperatures are going to rise by about four degrees over the next 100 years as predicted by the Intergovernmental Panel on Climate Change, that is where you get a huge difference in rates. What that suggests overall is that simply evolving to match these conditions may not be an option for many species."

The study indicates there is simply not enough time for species to change their morphologies - for example, by altering their bodies' shapes so they hold less heat - to compensate for rising heat levels. Too many generations of evolutionary change are required. Nor is moving habitat an option for many creatures. "Consider a species living on the top of a mountain," says Wiens. "If it gets too warm or dry up there, they can't go anywhere."

The crucial point of the study is that it stresses a fact that is often conveniently ignored by climate change deniers. It is not just the dramatic nature of the changes that lie ahead - melting icecaps, rising sea levels and soaring temperatures - but the extraordinary speed at which they are occurring. Past transformations that saw planetary temperatures soar took millions of years to occur. The one we are creating will take only a few generations to take place. Either evolution speeds up 10,000-fold, which is an unlikely occurrence, or there will be widespread extinctions.

# data[].attributes.attachment_link.title
Climate change is happening too quickly for species to adapt

# data[].attributes.attachment_link.description
mong the many strange mantras repeated by climate change deniers is the claim that even in an overheated, climate-altered planet, animals and plants will still survive by adapting to global warming. Corals, trees, birds, mammals and butterflies are already changing to the routine reality of global warming, it is argued.

# data[].attributes.headline
Linked article to Climate Change Scientific reference

# data[].attributes.subject
Linked article to Climate Change Scientific reference

# data[].attributes.attachment_link.description
Enter your email address below. If your address has been previously registered, you will receive an email with instructions on how to reset your password. If you don't receive an email, you should register as a new user

# data[].attributes.headline
Ten Species That Are Evolving Due to the Changing Climate

# data[].attributes.subject
Ten Species That Are Evolving Due to the Changing Climate

# data[].attributes.attachment_link.readable_text
Climate change is poised to become a serial killer. With rapid temperature swings around the world, ecosystems have been thrown into flux, exacerbating problems such as habitat loss that have already pushed many plant and animal species to the brink. Some biologists argue that Earth is on the verge of another major extinction event. The big question is whether plants and animals can adapt quickly enough to outpace climate change.

We often think of evolution as something that happens slowly, but that's not always the case. If the selection pressures are strong enough, evolution can happen over mere decades. For instance, an experiment growing brewer's yeast in environments with deadly concentrations of salt showed that the microbe population took a hit but then bounced back thanks to rapid changes in a couple genes over just 25 generations.

Identifying genetic adaptations in response to climate change can be tricky. Long-term data sets can tell us the most about whether a species is truly evolving, but it's hard to tell if any genetic differences were selected for climate reasons alone. What's more, not all genetic adaptations may be beneficial in the long term. And some species may not even need to evolve to survive. Physical or behavioral modifications made during an individual's lifetime may help enough members within a species thrive in a changing world.

Here are 10 species that may already be adapting to climate change-for better or worse:

Table Corals

Corals are highly sensitive to temperature changes in the ocean. Higher temperatures can cause bleaching, when corals spit out the colorful algae that live inside their tissues. Algae give corals nutrients in exchange for shelter, so bleaching can be a death sentence, especially for species in stressful, low-nutrient environments. A 2004 study suggested that coral populations might be shifting to favor corals with algae that are less sensitive to bleaching, but it's unclear if this involves inherited changes in corals' genes.

However, one species shows how evolution might come to the rescue. According to an April study, table corals (Acropora hyacinthus) can adapt to resist bleaching in warmer waters. On Ofu Island in American Samoa, A. hyacinthus lives in both hot and cool pools. In the lab, researchers tested corals from both environments to see how they reacted to increased heat. They found that only 20 percent of corals from the hot pools bleached, compared to 55 percent from the cool pools. Also, corals from cooler pools that spent a year transplanted in hot pools had an advantage-only 32.5 percent of those corals bleached in the lab tests. The results suggest that the species has the genetic material necessary to adapt and survive the heat, and that heat-tolerant corals might gain a reproductive advantage over time. Some researchers advocate growing heat tolerant corals and planting them in hard hit areas, but such human-assisted evolution garners controversy.

Thyme

Varieties of Mediterranean thyme (Thymus vulgaris) produce oils with different chemical compositions, and the ones with stronger smelling compounds like phenols are more effective at deterring herbivores. Producing phenols typically comes at a cost, though, as these plants are more sensitive to freezing. But in southern France's Saint-Martin-de-Londres basin, winters are getting warmer. Since the 1970s, the basin has seen fewer freezing nights during the cold season.

Looking at 24 populations across the basin in 1974 versus 2010, one study found an increase in the proportion of plants that produce phenolic compounds. These plants are even popping up in areas where they didn't grow in the 1970s. Since the plant's genes determine the chemical composition of its oils, it's likely that genetic changes are behind wild thyme's response to warmer winters.

Pink Salmon

Environmental factors often drive migratory behavior patterns in animals. For salmon, migration is crucial to their survival as a species, because the fish swim from the ocean and up freshwater streams to spawn. The need to migrate is so strong it is even written into their genes. In Auke Creek, Alaska, one pink salmon (Oncorhynchus gorbuscha) population is migrating about two weeks earlier than it was 40 years ago. So scientists looked at both genetic and migratory data over 32 years to see if genetic changes were behind the switch.

The team found that between 1983 and 2011, the frequency of a genetic marker for late migration dropped significantly. By 2011, late migrating fish only made up about 10 percent of the population. Over that same time period, the local water temperature has increased by about one degree Celsius on average, an uptick that's linked to climate change. The researchers argue that earlier migrating fish are better fit to handle warmer waters. Auke Creek salmon populations have held steady over the last few decades, and this adaptation may have made them more resilient.

Tawny Owls

A common nocturnal predator in the temperate forests of Europe, tawny owls (Strix aluco) come in two basic shades: brown and less brown. No matter their sex or age, an owl's feather color depends entirely on how much of a pigment called pheomelanin ends up in its plumage, something that is dictated by a variety of genes. Though regular brown is the dominant trait, the pale brown or grayish color helps some owls blend in with snowy trees and hide from predators. More snow typically equals more gray owls.

With milder winters in Finland, one population of tawny owls showed a significant uptick in brown-plumed owls over the last 28 years, according to a 2011 Nature Communications study. The researchers also saw a nationwide increase in brown owls over the last 48 years. It makes sense that natural selection might favor brown coloration: With less snow, brown owls are better at blending in with the surrounding forest, giving those birds a better chance to survive and reproduce.

Pitcher Plant Mosquitoes

In the bogs of eastern North America, the larvae of pitcher plant mosquitoes (Wyeomyia smithii) hibernate in winter and blossom into fully grown adults come spring, when they thrive on the nectar inside their namesake plants. As the days grow shorter, the mosquitoes are genetically programmed to hibernate. Mosquitos at the southern end of the species' range had already adapted to delay hibernation based on the longer growing season. But now northern populations are also hibernating later as global temperatures rise.

A 2001 study in PNAS showed that the genetic changes responsible for the shift can manifest in as little as five years, according to lab tests. In areas where the selection pressures are stronger, the change in hibernation behavior can happen even faster. Other studies hint that the Asian tiger mosquito, a carrier of West Nile virus, and the water strider are experiencing similar shifts in hibernation periods based on seasonal impacts of climate change.

Banded Snails

For banded snails (Cepaea nemoralis), shell coloration is determined not only by genes, but also by body temperature: Snails with light shells tend to be cooler customers. Scientists suspect that warmer temperatures in Europe might make the lighter coloration become more prevalent. One study published in Global Change Biology found that banded snail populations sampled at 16 sites in the Netherlands in 1967 and again in 2010 had an increasing proportion of yellow shells compared to brown ones. Over 43 years, the area has also seen a 1.5° to 2°F increase in annual temperature. The trend even held for shaded areas, where one might expect darker shells to provide better camouflage.

But the verdict may still be out on whether climate change is causing the snails to evolve. Another study, published in PLOS ONE in 2011, found no difference in the prevalence of light-colored shells across the board. The researchers hypothesize that individual snails are instead changing how they regulate their body temperature to cope with the changing climate.

Sockeye Salmon

In the Columbia River, sockeye salmon (Oncorhynchus nerka) are migrating earlier every year in the spring and early summer to spawn. A 2011 study in American Naturalist examined this migration trend over 60 years to see if warmer river temperatures might be to blame. Luckily, sockeye salmon migration counts go back decades, so the researchers were able to factor daily migration data into statistical modeling of historic environmental pressures. Evolution in response to higher water temperatures proved the most likely explanation for about two-thirds of the shift, while individual adaptation to river flow changes could explain the rest.

Red Squirrels

The southwest Yukon has seen increasingly warm springs and a drier environment, encouraging white spruce trees to produce more cones-and giving North American red squirrels (Tamiasciurus hudsonicus) more to eat. In red squirrels, the more cones females eat in the fall, the earlier they give birth. Looking at an individual population of red squirrels near Kluane Lake, Canada, researchers did see a shift to earlier birthing times of almost 2 days per year over the last 10 years. Birthing time can vary a bit, but the team argues that the data can only be explained if at least some of the shift is attributed to genetic changes inherited over generations.

Fruit Flies

Species can vary a lot based on their geography. In the case of the common fruit fly (Drosophila melanogaster), genetic variants correspond to populations living at different latitudes, and specific enzyme mutations can serve as biomarkers. So researchers examined the prevalence of three protein forms in fruit flies along the east coast of Australia between 1979 to 1982 and 2002 to 2004. Southern Australia is more temperate and tropical, while northern Australia is dry and hot. The team found that many fruit flies living in Southern Australia now have the genetic mutations common in more northern populations-as if they'd moved nearly 4 degrees in latitude. Scientists suggest that these changes are linked to coping with a warmer and drier climate, and researchers have found similar trends in Europe and North America.

Great Tits

Sometimes organisms are slow to adapt. In Holland's Hoge Veluwe Park, caterpillars are maturing earlier each year as spring comes earlier. But their predators, great tits (Parus major), aren't always changing their schedule to hatch when the caterpillars are at their peak, and bird numbers are dropping. As with the hibernating mosquitoes, great tits have a genetic trigger that spurs them to lay eggs when spring arrives. But there's some variation in how much an individual bird can tweak its egg-laying date in response to an earlier spring. A study of 833 great tits in Hoge Veluwe over 32 years did find greater genetic selection for birds that could vary their egg-laying time to match the caterpillars' arrival. If this trend continues, it could save them from decline, but it remains unclear whether they can change fast enough to beat rising temperatures.

Get the latest Science stories in your inbox.

# data[].attributes.attachment_link.title
Ten Species That Are Evolving Due to the Changing Climate

# data[].attributes.attachment_link.description
From tropical corals to tawny owls, some species are already being pushed to evolve-but adaptation doesn't guarantee survival

# data[].attributes.attachment_link.readable_text
Rising sea levels. Raging storms. Searing heat. Ferocious fires. Severe drought. Punishing floods. The effects of climate change are already threatening our health, our communities, our economy, our security, and our children's future.

What can you do? A whole lot, as it turns out. Americans, on average, produce 21 tons of carbon a year, about four times the global average. Personal action is, of course, no substitute for meaningful government policies. We still must limit carbon pollution and aggressively move away from dirty fossil fuels toward cleaner power.

But it's important to remember the equally vital contributions that can be made by private citizens-which is to say, by you. "Change only happens when individuals take action," says clean energy advocate Aliya Haq. "There's no other way, if it doesn't start with people."

Here are a dozen easy, effective ways each one of us can make a difference.

1. Speak up!

What's the single biggest way you can make an impact on global climate change? "Talk to your friends and family, and make sure your representatives are making good decisions," Haq says. By voicing your concerns-via social media or, better yet, directly to your elected officials-you send a message that you care about the warming world. Encourage Congress to enact new laws that limit carbon emissions and require polluters to pay for the emissions they produce. "The main reason elected officials do anything difficult is because their constituents make them," Haq says. You can help protect public lands, stop offshore drilling, and more here.

2. Power your home with renewable energy.

Choose a utility company that generates at least half its power from wind or solar and has been certified by Green-e Energy, an organization that vets renewable energy options. If that isn't possible for you, take a look at your electric bill; many utilities now list other ways to support renewable sources on their monthly statements and websites.

3. Weatherize, weatherize, weatherize.

"Building heating and cooling are among the biggest uses of energy," Haq says. Indeed, heating and air-conditioning account for almost half of home energy use. You can make your space more energy efficient by sealing drafts and ensuring it's adequately insulated. You can also claim federal tax credits for many energy efficiency home improvements. To help you figure out where to start, you could also get a home energy audit, which some utilities offer free of charge. (Alternatively, you can hire a professional to come to your home and perform one; the Inflation Reduction Act offers a partial tax credit for this.) The EPA's Home Energy Yardstick gives you a simple assessment of your home's annual energy use compared with similar homes.

4. Invest in energy-efficient appliances.

Since they were first implemented nationally in 1987, efficiency standards for dozens of appliances and products have kept 2.3 billion tons of carbon dioxide out of the air. That's about the same amount as the annual carbon pollution coughed up by nearly 440 million cars. "Energy efficiency is the lowest-cost way to reduce emissions," Haq says. When shopping for refrigerators, washing machines, heat pump water heaters, and other appliances, look for the Energy Star label. It will tell you which are the most efficient. (There may also be rebates to earn from your purchase of Energy Star-certified products.)

And when you're ready to swap out your old machines, don't just put them on the curb: Recycling an old refrigerator through the EPA's Responsible Appliance Disposal Program can prevent an additional 10,000 pounds of carbon pollution because the global-warming pollutants in the refrigerants and foam would be properly captured rather than vented to the air.

5. Reduce water waste.

Saving water reduces carbon pollution, too. That's because it takes a lot of energy to pump, heat, and treat your water. So take shorter showers, turn off the tap while brushing your teeth, and switch to WaterSense-labeled fixtures and appliances. The EPA estimates that if just one out of every 100 American homes were retrofitted with water-efficient fixtures, about 100 million kilowatt-hours of electricity per year would be saved-avoiding 80,000 tons of global warming pollution.

6. Actually eat the food you buy-and compost what you can't.

Approximately 10 percent of U.S. energy use goes into growing, processing, packaging, and shipping food-about 40 percent of which winds up in the landfill. "If you're wasting less food, you're likely cutting down on energy consumption," Haq says. As for the scraps you can't eat or the leftovers you don't get to, collect them in a compost bin instead of sending them to the landfill where they release methane. Recycling food and other organic waste into compost provides a range of environmental benefits, including improving soil health, reducing greenhouse gas emissions, recycling nutrients, and mitigating the impact of droughts.

7. Buy better bulbs.

LED light bulbs use one-sixth the amount of energy to deliver the same amount of light as conventional incandescents and last at least 10 times longer. They're also cheaper in the long run: A 10-watt LED that replaces your traditional 60-watt bulb will save you $125 over the light bulb's life. And because the average American home has around 40 to 50 light bulbs, this is a simple swap that will reap huge rewards. If every household in the United States replaced just one incandescent with an Energy Star-labeled LED, we would prevent seven billion pounds of carbon pollution per year. That's equivalent to the emissions of about 648,000 cars.

8. Pull the plug(s).

Taken together, the outlets in your home are likely powering about 65 devices-an average load for a home in the United States. Audio and video devices, cordless vacuums and power tools, and other electronics use energy even when they're not charging. This "idle load" across all U.S. households adds up to the output of 50 large power plants in the country. So don't leave fully charged devices plugged into your home's outlets, unplug rarely used devices or plug them into power strips and timers, and adjust your computers and monitors to automatically power down to the lowest power mode when not in use.

9. Drive a fuel-efficient vehicle.

Gas-smart cars, such as hybrids and fully electric vehicles, save fuel and money. And once all cars and light trucks meet 2025's clean car standards, which means averaging 54.5 miles per gallon, they'll be a mainstay. For good reason: Relative to a national fleet of vehicles that averaged only 28.3 miles per gallon in 2011, Americans will spend $80 billion less at the pump each year and cut their automotive emissions by half. Before you buy a new set of wheels, compare fuel-economy performance here.

10. Maintain your ride.

If all Americans kept their tires properly inflated, we could save 1.2 billion gallons of gas each year. A simple tune-up can boost miles per gallon anywhere from 4 percent to 40 percent, and a new air filter can get you a 10 percent boost. Also, remove unnecessary accessories from your car roof. Roof racks and clamshell storage containers can reduce fuel efficiency by as much as 5 percent.

11. Rethink planes, trains, and automobiles.

Choosing to live in walkable smart-growth cities and towns with quality public transportation leads to less driving, less money spent on fuel, and less pollution in the air. Less frequent flying can make a big difference, too. "Air transport is a major source of climate pollution," Haq says. "If you can take a train instead, do that." If you must fly, consider purchasing carbon offsets to counterbalance the hefty carbon pollution associated with flying. But not all carbon offset companies are alike. Do your homework to find the best supplier.

12. Reduce, reuse, and recycle.

In the United States, the average person generates 4.5 pounds of trash every day. Fortunately, not all the items we discard end up in landfills; we recycle or compost more than one-third of our trash. In 2014 this saved carbon emissions equivalent to the yearly output of 38 million passenger cars. But we could be doing so much more. "Reduce should always be the number-one priority," says NRDC senior resource specialist Darby Hoover. And to reap the environmental benefits of "recyclable" goods, you must recycle according to the rules of your municipality, since systems vary widely by location. Search your municipality's sanitation department (or equivalent) webpage to learn exactly what you can place in the recycling bin, as counties and cities often differ in what they accept.
This story was originally published on April 20, 2022 and has been updated with new information and links.

# data[].attributes.attachment_link.description
There are many ways to prevent global warming from becoming worse. Many nations have put laws into place to fight climate change -- here's what you can do.

# data[].attributes.attachment_link.readable_text
Can I help nature to help us?

Yes! We can all take notice of our environment. We can learn how our planet works. We can learn how to live on it without making a mess of it. We can help to keep it magnificent for ourselves, our children and grandchildren, and other living things besides us.

Some of the ways you can help may have to wait until you are a little older-like choosing an energy-efficient car, installing solar panels on the roof of your house, or choosing a "green career."

But there are many important ways you can help right now.

You can help by growing your own vegetables and fruits. You can help by planting a tree. Your new plants and trees will help to remove the greenhouse gas CO ₂ from the air. If you grow some of your own food, you will also help to prevent more CO ₂ from entering the air from the fossil-fuel-burning trucks, planes, and ships that transport your food to you from far away.

How can I reduce my "carbon footprint"?

Your carbon footprint is the amount of carbon dioxide released into the air because of your own energy needs. You need transportation, electricity, food, clothing, and other goods. Your choices can make a difference.

Swap old incandescent light bulbs for the new compact fluorescent lights (CFLs). They use only 25% as much electricity to give the same light. They last ten times longer.

Turn off lights, TVs, computers, when you do not need them.

Unplug! Any electronic gadget you can turn on with a remote (TV, DVD player, Nintendo, Xbox) uses power even when it is "off." Appliances with a digital clock (like a coffee maker) or a power adapter (like a laptop computer) also suck power like a sneaky vampire. Plug these kinds of things into a surge protector or power strip that has an on/off switch. Then you can shut off all the power without unplugging each gadget.

There are even power strips that glow to show you how much power is going through them, and power strips you can control from your computer or iPhone.

Turn up the thermostat on the air conditioning when it's hot. Use fans if you're still hot. They use much less power.

Turn down the thermostat on the heating when it's cold. Sweaters, blankets, and socks are good for you and better for the planet.

Walk or ride your bike instead of taking a car everywhere. Even a 2-mile car trip puts 2 pounds of CO ₂ into the atmosphere!

If you must ride, carpool.

Stay out of the drive thru! When you go to a fast-food place, ask your driver to park the car and let you walk inside, rather than sitting in a line of cars with the engine running and polluting.

How can I reduce my trash pile?

Ask your parents to buy reusable grocery bags. Help them to remember to get them out of the car and take them into the store.

Recycle everything you can. If your city does not pick up recycled materials, find out who you can talk to about starting this service. You should be recycling paper, aluminum cans, cardboard, food cans, plastic, glass, newspapers, magazines, junk mail, phone books, and anything else made of paper.

Shop thrift stores. "BYOM." Bring your own mug. That's what you can tell your parents when they stop to buy their morning coffee. Use less paper whenever possible. Save the trees.

Drink tap water-filtered, if you like-instead of bottled water. Carry your drinking water in a reusable bottle. Plastic water bottles are an environmental disaster!

Use fewer containers. Buy the product that uses less packaging material. Even if you recycle packaging materials, it takes energy to create them in the first place and energy to remake them into something else.

Practice by playing "Recycle This!."

Do I need to save water too?

People and animals in many parts of the world do not have clean, safe water to drink. As many more regions are hit by drought, this problem will become even more serious. The sooner we start conserving water, the better off we all will be. Be aware of how much water you use.

Imagine you live in a recreational vehicle (RV), and your water tank holds only 50 gallons. Every time you turn on the water, the noisy electric water pump has to turn on too, sucking up your RV's battery power. Would you keep the water running while you brush your teeth? Would you spend 15 minutes in the shower using up all the water in the tank and depleting the battery? Would you plant a thirsty lawn in front of your RV if you were parked in the desert? Of course not!

How can I make a real difference?

You can choose a "green career." You can help to solve climate change problems and challenges. These are the exciting careers of the future. They range from designing satellites for NASA to fixing wind-energy generators to planning drought-tolerant landscapes for homes and parks. Many of the possible careers haven't even been thought of yet. You could invent your own career! Check out some Green Careers.

# data[].attributes.attachment_link.description
We can do a lot, including planning for a green career.

# data[].attributes.attachment_link.description
Climate change threatens the iconic beaches of San Diego. A recent study by San Francisco State University economists found that, by 2050, San Diegans could lose 20% of Torrey Pines State Beach to flooding and erosion, resulting in annual losses of:

# data[].attributes.attachment_link.readable_text
SEforALL and partners have installed solar PV and battery systems at six hospitals in Sierra Leone to improve the reliability of their electricity supplies, supporting the life-saving efforts of doctors and nurses.

WATCH OUR CAMPAIGN VIDEO

Register now for the 2024 SEforALL Global Forum

Read more

Explore our new Strategic Plan for 2024-2026

Read more

Energy Transition and Investment Plans for universal energy access and net-zero emissions

Developing countries are committed to improving access to energy while contributing to the global fight against climate change. Energy Transition and Investment Plans detail the actions and investments needed to reach their goals, helping countries attract support.

READ MORE

Sustainable Energy for All (SEforALL) is an international organization that works in partnership with the United Nations and leaders in government, the private sector, financial institutions, civil society and philanthropies to drive faster action towards the achievement of Sustainable Development Goal 7 (SDG7).

SDG7 calls for "affordable, reliable, sustainable and modern energy for all" by 2030. Together, we need to provide energy access to billions of people without electricity or clean cooking, double the rate of improvement in energy efficiency and substantially increase the share of renewables in the energy mix.

# data[].attributes.attachment_link.description
Sustainable Energy for All (SEforALL) works in partnership with the UN and world leaders to drive faster action towards Sustainable Development Goal 7 (SDG 7) in line with the Paris Agreement.

# data[].attributes.attachment_link.title
Environmental Principles and Concepts - California Education and the Environment Initiative (EEI)

# data[].attributes.attachment_link.description
Students and teachers need not memorize the five environmental principles and fourteen supporting concepts. Rather, they are "big ideas" intended to inform standards-based instruction and fuel student inquiry. Teachers can support environmental literacy by helping students to understand and apply the EP&Cs across academic disciplines and in the real world.

# data[].attributes.attachment_link.description
The Keeling Curve is a daily record of global atmospheric carbon dioxide concentration maintained by Scripps Institution of Oceanography at UC San Diego.

# data[].attributes.body
NOAA Climate.gov and a community of educational and science partners have developed and organized supporting resources and programs for those who want to teach climate and energy science, backed by some of the nation's most experienced professional educators, scientists, and engineers.

# data[].attributes.attachment_link.description
The Toolbox for Teaching Climate & Energy has been created to organize and highlight resources from numerous educational and science partners and programs all working toward the supporting teachers and education systems.

# data[].attributes.headline
2017 U.S. Climate Science Special Report

# data[].attributes.subject
2017 U.S. Climate Science Special Report

# data[].attributes.body
This report is an authoritative assessment of the science of climate change, with a focus on the United States. It represents the first of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990.

# data[].attributes.attachment_link.description
This report is an authoritative assessment of the science of climate change, with a focus on the United States. It represents the first of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990.

# data[].attributes.headline
Climate Literacy and Energy Awareness Network (CLEAN) Portal

# data[].attributes.subject
Climate Literacy and Energy Awareness Network (CLEAN) Portal

# data[].attributes.body
The three key components of the CLEAN project are:

1. The CLEAN Collection of Climate and Energy Science resources- high-quality, digital resources---including learning activities, visualizations, videos, and short demonstrations/experiments---geared toward educators of students in secondary through undergraduate levels.

2. Guidance in Teaching Climate and Energy Science – pages designed to help educators understand and be equipped to teach the big ideas in climate and energy science.

3. The CLEAN Network – a community of professionals committed to improving climate and energy literacy.

# data[].attributes.attachment_link.readable_text
Our team of educators and scientists has reviewed and organized the best free teaching resources for K-12 through college.

Get Started Teaching Climate and Energy

Easy-to-read explanations of science and policy, designed to step students through the key principles of climate and energy

Suggested teaching approaches, selected for various grade levels

Spanish-language versions

Supporting materials from the CLEAN reviewed collection

Culturally relevant climate teaching

Explore Teaching Climate and Energy

Posted: Oct 18 2023

Join us for the second Accelerating Climate Capacity, Engagement, and Leadership Summit (ACCELS), convened by the CLEAN Network! Thursday, November 16 th 2-5pm ET

Posted: Apr 1 2023

Check out CLEAN's new pages about helping teachers address Climate Mental health and our upcoming webinar on this topic.

Posted: Mar 1 2023

CLEAN has translated more of our pages into Spanish including elementary teaching, culturally relevant teaching, and controversial teaching! Check out the Guidance and Toolbox pages

Posted: Jan 15 2023

Register for the Spring 2023 CLEAN Webinar Series! Topics include teaching about climate, systems thinking, consequences & solutions, and energy!

RSS

Teaching Climate and Energy with NGSS

Our resources are aligned to the standards. You can explore the key standards related to climate and energy or find a resource that supports a specific standard.

Find NGSS-tagged materials in the CLEAN collection

Design your own three-dimensional classroom units

Explore Teaching Climate and Energy with NGSS

Strengthen your Teaching

Find professional development tools and support for teaching climate and energy.

Whether you're designing lessons, adapting to online teaching, or building a constructive classroom atmosphere, we have tools to help.

Educator Toolbox

Get Involved with CLEAN

CLEAN is a community effort, brought to you by scores of educators, scientists, and curriculum developers. There are many ways to become part of this project.

Get Involved

About CLEAN

CLEAN is the Climate Literacy and Energy Awareness Network.
Our primary efforts are:

to steward a reviewed collection of free, high-quality teaching materials for teaching climate and energy

to support the CLEAN Network, a community of professionals committed to improving climate and energy literacy.

Learn more about CLEAN
CLEAN recognizes the disproportionate impact climate change has on Communities of Color and the importance of incorporating social and environmental justice into climate education. Please see our cultural acknowledgements pages for more information.

Key:

Events in blue: Events from CLEAN

Events in black: Professional development opportunities from CLEAN

Events in green: Events from the Climate and Energy Literacy Community

Suggest an event

See Ongoing Events and Opportunities

# data[].attributes.attachment_link.keywords[]
teach the earth incorporating societal issues climate change

# data[].attributes.attachment_link.title
CLEAN: Committed to Climate and Energy Education

# data[].attributes.attachment_link.description
Our team of educators and scientists has reviewed and organized the best free teaching resources for K-12 through college. Go Entire Collection Activities Videos Visualizations Featured Resource HEART Force ...

# data[].attributes.headline
Climate and Energy Educational Resource Collection: Ocean Warming and Acidification

# data[].attributes.subject
Climate and Energy Educational Resource Collection: Ocean Warming and Acidification

# data[].attributes.body
The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.headline
Climate and Energy Educational Resource Collection: Ice

# data[].attributes.subject
Climate and Energy Educational Resource Collection: Ice

# data[].attributes.body
This is a collection of 356 reviewed ice climate and energy resources.

The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.headline
Climate and Energy Educational Resource Collection: Sea Level Rise

# data[].attributes.subject
Climate and Energy Educational Resource Collection: Sea Level Rise

# data[].attributes.body
This is a collection of 169 reviewed sea level rise climate and energy resources.

The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.headline
Climate and Energy Educational Resource Collection: Causes of Climate Change - Cyclical and Natural Changes

# data[].attributes.subject
Climate and Energy Educational Resource Collection: Causes of Climate Change - Cyclical and Natural Changes

# data[].attributes.body
This is a collection of 57 reviewed "Causes of Climate Change - Cyclical and Natural Changes" climate and energy resources.

The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.headline
Teaching Climate and Energy with the Next Generation Science Standards: Physical Sciences

# data[].attributes.subject
Teaching Climate and Energy with the Next Generation Science Standards: Physical Sciences

# data[].attributes.body
CLEAN has aligned 102 high school reviewed climate and energy resources to HS NGSS  Physical Sciences.

The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.headline
Teaching Climate and Energy with the Next Generation Science Standards: Life Sciences

# data[].attributes.subject
Teaching Climate and Energy with the Next Generation Science Standards: Life Sciences

# data[].attributes.body
CLEAN has aligned 102 high school reviewed climate and energy resources to HS NGSS  Life Sciences.

The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy frameworks, and the Next Generation Science Standards .

# data[].attributes.attachment_link.description
NGSS & CLEAN at a Glance " The CLEAN Collection is a high-quality and rigorously reviewed collection of climate and energy educational resources aligned with the Climate Literacy and the Energy Literacy ...

# data[].attributes.body
This CLEAN selected animated visualization represents a time history of atmospheric carbon dioxide in parts per million (ppm) from 1979 to 2016, and then back in time to 800,000 years before the present.

# data[].attributes.attachment_link.title
Time History of Atmospheric CO2 | NOAA Climate.gov

# data[].attributes.attachment_link.description
This animated visualization represents a time history of atmospheric carbon dioxide in parts per million (ppm) from 1979 to 2016, and then back in time to 800,000 years before the present.

# data[].attributes.headline
Energy Literacy: Essential Principles and Fundamental Concepts for Energy Education

# data[].attributes.subject
Energy Literacy: Essential Principles and Fundamental Concepts for Energy Education

# data[].attributes.body
Energy Literacy: Essential Principles and Fundamental Concepts for Energy Education is an interdisciplinary approach to teaching and learning about energy. The framework identifies seven Essential Principles and a set of Fundamental Concepts to support each principle. Access reviewed resources and supporting materials at CLEAN

# data[].attributes.attachment_link.title
Energy Literacy: Essential Principles for Energy Education

# data[].attributes.attachment_link.description
Energy Literacy: Essential Principles for Energy Education

# data[].attributes.headline
Oceans Are Losing Oxygen—and Becoming More Hostile to Life

# data[].attributes.subject
Oceans Are Losing Oxygen—and Becoming More Hostile to Life

# data[].attributes.attachment_link.readable_text
Free to the Public, the " World Ocean Festival Speaker Forum sponsored by National Geographic Encounter: Ocean Odyssey" will feature dialogue with leading explorers, scientists and entrepreneurs on NYC's Governors Island on June 4

Marlin and sailfish are the oceans' perfect athletes. A marlin can outweigh a polar bear, leap through the air, and traverse the sea from Delaware to Madagascar. Sailfish can outrace nearly every fish in the sea. Marlin can hunt in waters a half mile down, and sailfish often head to deep waters too.

Yet in more and more places around the world, these predators are sticking near the surface, rarely using their formidable power to plunge into the depths to chase prey.

The discovery of this behavioral quirk in fish built for diving offers some of the most tangible evidence of a disturbing trend: Warming temperatures are sucking oxygen out of waters even far out at sea, making enormous stretches of deep ocean hostile to marine life.

"Two hundred meters down, there is a freight train of low-oxygen water barreling toward the surface," says William Gilly, a marine biologist with Stanford University's Hopkins Marine Station, in Pacific Grove, California. Yet, "with all the ballyhoo about ocean issues, this one hasn't gotten much attention."

These are not coastal dead zones, like the one that sprawls across the Gulf of Mexico, but great swaths of deep water that can reach thousands of miles offshore. Already naturally low in oxygen, these regions keep growing, spreading horizontally and vertically. Included are vast portions of the eastern Pacific, almost all of the Bay of Bengal, and an area of the Atlantic off West Africa as broad as the United States.

Globally, these low-oxygen areas have expanded by more than 1.7 million square miles (4.5 million square kilometers) in the past 50 years.

This phenomenon could transform the seas as much as global warming or ocean acidification will, rearranging where and what creatures eat and altering which species live or die. It already is starting to scramble ocean food chains and threatens to compound almost every other problem in the sea.

Scientists are debating how much oxygen loss is spurred by global warming, and how much is driven by natural cycles. But they agree that climate change will make the losses spread and perhaps even accelerate.

"I don't think people realize this is happening right now," says Lisa Levin, an oxygen expert with the Scripps Institution of Oceanography, in San Diego.

Bad Water Rising

Few understand marlin and sailfish better than biologist Eric Prince. He has studied them in Jamaica, Brazil, the Ivory Coast, and Ghana. He has examined their ear bones in Bermuda, taken tissue samples in Panama, and gathered their heads-with bayonet-like bills still attached-during fishing contests in Puerto Rico.

One day a decade ago, while tracking satellite tags attached to these fish, Prince saw something bizarre: Marlin off North Carolina fed in waters as deep as 2,600 feet (800 meters). But marlin off Guatemala and Costa Rica hovered high in the water, almost never descending beyond a few hundred feet. Sailfish followed a similar pattern.

These billfish have special tissues in their heads that keep their brains warm in deep water. So why were they bunching up at the ocean's surface?

The culprit, it turned out, was a gigantic pool of low-oxygen water deep off Central America. These fish were staying up high, trying to avoid suffocating below.

Prince's discovery came just as other scientists were figuring out that rising temperatures were expanding natural low-oxygen zones in the deep ocean, pushing them skyward by as much as a meter (three feet) per year.

Over the next decade, researchers figured out that this change already was driving marine creatures-sailfish, sharks, tuna, swordfish, and Pacific cod, as well as the smaller sardines, herring, shad, and mackerel they eat-into ever narrower bands of oxygen-rich water near the surface.

"It leaves just a very thin lens on the top of the ocean where most organisms can live," says Sarah Moffitt, of the Bodega Marine Laboratory at the University of California, Davis.

Congregating alongside their prey appears to be making some bigger fish fatter, as they burn less energy hunting. But living in such a compressed area also may be speeding the decline of top predators such as tuna, sailfish, and marlin by making them more accessible to fishing fleets.

"It makes the predators much more likely to be caught by the longline fleet," says Prince, of the National Oceanic and Atmospheric Administration's Southeast Fisheries Science Center in Florida. "Very slightly, every year, they become more and more susceptible to overfishing."

Oxygen is so central to life, even in the marine world, that its loss is harming animals in countless other ways, too.

Warming Waters Deplete Oxygen

Fish, squid, octopus, and crab all draw dissolved oxygen from the water. And just as oxygen levels shift with elevation, oxygen at sea varies with depth. But in the ocean, oxygen is also dynamic, changing daily and seasonally with weather and tides or over years with cycles of warming and cooling.

Oxygen gets into the sea in two ways: through photosynthesis, which takes place only near the top where light penetrates, or through the mixing of air and water at the surface by wind and waves.

Deep ocean waters hold far less oxygen than surface waters because they haven't been in contact with air for centuries. And in many places, decomposing organic matter raining down from the surface uses up what little oxygen remains. These natural deep-water "oxygen minimum zones" cover great swaths of ocean interior.

They are far different from hypoxic coastal dead zones, which are multiplying, too, with more than 400 now reported worldwide. Dead zones are caused by nitrogen and other nutrients as rivers and storms flush pollution from farms and cities into nearshore waters.

The expansion of deep-sea low-oxygen zones, on the other hand, is driven by temperature. Warm water carries less dissolved oxygen. It's also lighter than cold water. That leaves the ocean segregated in layers, restricting delivery of fresh oxygen to the deep and making these oxygen-poor zones much bigger.

"The natural thing to expect is that as the ocean gets warmer, circulation will slow down and get more sluggish and the waters going into the deep ocean will hang around longer," says Curtis Deutsch, a chemical oceanography professor at the University of Washington, in Seattle. "And indeed, oxygen seems to be declining."

The zone off West Africa that's as big as the continental United States has grown by 15 percent since 1960-and by 10 percent just since 1995. At 650 feet (200 meters) deep in the Pacific off southern California, oxygen has dropped 30 percent in some places in a quarter century.

Many scientists already suspect global warming is partly to blame for this transformation. Deutsch and others, however, think oxygen declines so far have been driven by complicated natural factors. Ocean conditions vary so much normally that they might be experiencing an unusual period of depletion-one that could moderate soon.

But Deutsch called that "a very, very thin silver lining."

"Right now in the ocean, there is incredibly strong internal variability and a very tiny climate trend on top of it," he says. "But my sense from all the model simulations we've done is that we're on the verge of having that trend emerge from the noise."

Some species, such as Dover sole, may be unaffected, but many areas could be left with far fewer higher life forms.

Most researchers project that oxygen loss will keep driving many species toward the surface, reducing habitat for some and concentrating prey for birds, turtles, and other surface predators.

Winds in some regions will draw the oxygen-depleted water to the surface and push it onto shallower continental shelves. When oxygen drops there, some sensitive species that can't move die. Even survivors experience stress, which can make them vulnerable to predators, disease, or overfishing.

This has already begun. The waters of the Pacific Northwest, starting in 2002, intermittently have gotten so low in oxygen that at times they've smothered sea cucumbers, sea stars, anemones, and Dungeness crabs. This biologically rich region-where winds draw waters from the deep 50 miles (80 kilometers) offshore and push them to the beach-is temporarily transformed into a lifeless wasteland.

"I look at it as a major reshaping of the ecosystem," says Jack Barth, a chemical oceanographer at Oregon State University, in Corvallis.

Localized die-offs aren't even the most disruptive effect of depleted oxygen.

"Changes in oxygen turn out to be really important in determining where organisms are and what they do," says marine biologist Francis Chan, also at Oregon State University.

The fate of some odd little fish suggests the consequences can be enormous.

Into the Light

Since the 1950s, researchers every year have dropped nets 1,000 feet (300 meters) down to catalog marine life many miles off California. Most track commercially important species caught by the fishing industry. But J. Anthony Koslow tallies fish often credited with keeping marine systems functioning soundly-tiny midwater bristlemouths, the region's most abundant marine species, as well as viperfish, hatchetfish, razor-mouthed dragonfish, and even minnow-like lampfish.

All are significant parts of the seafood buffet that supports life in the eastern Pacific, and all are declining dramatically with the vertical rise of low-oxygen water.

"If it was a 10 percent change, it wouldn't have been worth noting, but they've declined by 63 percent," says Koslow, of the Scripps Institution of Oceanography. And "what's been amazing is it's across the board-eight major groups of deep-sea fishes declining together-and it's strongly correlated with declining oxygen."

Most of these fish spend their days swimming hundreds of feet down, just above low-oxygen water. Many are black, camouflaged by the dark, deep waters where light never reaches. They rise at night to feed on plankton.

Koslow can't say precisely why these fish populations have collapsed. But he suspects they, too, now spend more time closer to the surface seeking oxygen. That puts these fish during the day in a region where light penetrates, making them easier pickings for birds, marine mammals, rockfish, and other sight-feeders.

If that's the case, Koslow says, "the ramifications would be huge."

Such tiny fish are a massive food source around the world. Globally, they account for far more mass in the sea than the entire world's catch of fish combined. But there isn't enough historical data in other parts of the world to determine if the trend is unique to California.

"They are central to the ecology of the world's oceans," Koslow says.

Scientists suspect these fish already may be partly responsible for at least one surprising change-a massive northward expansion between 1997 and 2010 of the northern Pacific Ocean's most ravenous visitor, the Humboldt squid.

Once found from South America to Mexico, with occasional forays into California, the Humboldt squid has moved so far north that in recent years it has been seen off Alaska. Researchers tested squid in tanks and found low oxygen was hard on them, too, even though the jumbo squid could slow its metabolism. Yet here they were, faring so well at the edge of low-oxygen areas they had become a master predator of midwater fish.

"These squid are out-competing all the tunas and sharks and marine mammals that may want to feed in this zone," Stanford's Gilly says.

Researchers did not directly connect the expansion of the squid's feeding area to rising oxygen-poor water. But Koslow linked low-oxygen water to shifts in where the midwater fish on the squid's menu live. And scientists now can draw a direct line between where those fish went and the squid's northward march, Gilly says.

"I think there might be a sweet spot for Humboldt squid, where low oxygen, food, and light are in perfect balance-and that's accounting for their expansion," Gilly says.

Still, the squid's expansion was not subtle. Tracking its causes almost certainly is simpler than unspooling other impacts. And oxygen loss exacerbates other issues. Marine creatures need more oxygen in warmer waters, for example. Climate change means they increasingly will have less.

"I think we are changing the world; I just don't think the responses are going to be as predictable as we think," says Francisco Chavez, senior scientist with California's Monterey Bay Aquarium Research Institute. "I think there are a slew of surprises ahead."

And how low-oxygen areas will affect everything else depends on how much they spread.

Looking Back to See Ahead

To answer that question, scientists recently examined marine sediment cores from a period of glacial melt 17,000 to 11,000 years ago.

During that time, global average air temperatures rose 3 to 4 degrees Celsius, the closest historical analog for the projected future, says study co-author Tessa Hill, of the Bodega Marine Laboratory. "The idea here is ... let's take an interval with somewhat analogous warming and see how low-oxygen zones responded," Hill says.

The results: Low-oxygen areas exploded around the world.

"What we found is that their expansion was just extremely large and abrupt," says lead author Moffitt. "Their footprint across ocean basins grew much more than we had anticipated."

One low-oxygen region off Chile and Peru-combined, the two countries now have an anchovy fleet that makes up the world's largest single-species fishery-was much larger then, thousands of years ago. It stretched from 9,800 feet (3,000 meters) deep to within 490 feet (150 meters) of the surface. And off California, low-oxygen waters came far closer to the surface than they do today.

Their research showed that "environments we might think of as stable, like the deep ocean, may not be so stable at all," Moffitt says.

In the blink of an eye, geologically speaking, entire ocean basins changed. And many scientists suspect they are doing so once again, at a cost they can't yet quantify.
Follow Craig Welch on Twitter.

# data[].attributes.attachment_link.title
Oceans Are Losing Oxygen-and Becoming More Hostile to Life

# data[].attributes.attachment_link.description
Free to the Public, the " World Ocean Festival Speaker Forum sponsored by National Geographic Encounter: Ocean Odyssey" will feature dialogue with leading explorers, scientists and entrepreneurs on NYC's Governors Island on June 4 Marlin and sailfish are the oceans' perfect athletes.

# data[].attributes.headline
Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific

# data[].attributes.subject
Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific

# data[].attributes.attachment_link.readable_text
Arnaud Bertrand,

Alexis Chaigneau,

Salvador Peraltilla,

Jesus Ledesma,

Michelle Graco,

Florian Monetti,

Francisco P. Chavez

Subject Areas

For more information about PLOS Subject Areas, click here.

We want your feedback. Do these Subject Areas make sense for this article? Click the target next to the incorrect Subject Area and let us know. Thanks for your help!

Abstract

Background

In the southeastern tropical Pacific anchovy ( Engraulis ringens) and sardine ( Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world's most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences.

Methodology/Principal Findings

A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem.

Conclusions/Significance

For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems.

Citation: Bertrand A, Chaigneau A, Peraltilla S, Ledesma J, Graco M, Monetti F, et al. (2011) Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific. PLoS ONE 6(12): e29558. https://doi.org/10.1371/journal.pone.0029558

Editor: Caroline P. Slomp, Utrecht University, The Netherlands

Received: October 4, 2011; Accepted: November 30, 2011; Published: December 28, 2011

Copyright: © 2011 Bertrand et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: These authors have no support or funding to report.

Competing interests: The authors have declared that no competing interests exist.

Introduction

It has been known for some time that oxygen plays a strong role in regulating the coastal benthic communities off the southeastern tropical Pacific and other low oxygen environments [1]. Oxygen levels over the continental shelf off Peru are on average anoxic and only anaerobic filamentous bacteria can survive in the benthos [1]-[4]. Interannually, El Niño oxygenates these benthic habitats that are then colonized by communities that are more typical of other oxygenic environments [1], [4]. Much less is known about the role of oxygen in regulating pelagic ecosystems, in particular metazoan organisms. Given recent reports that oxygen in the world oceans might be decreasing [5]-[7] it is critical that we understand the role of oxygen in structuring pelagic ocean ecosystems. To gain some insights we look at an ecosystem, the coastal southeastern tropical Pacific, which has been experiencing very low, anoxic oxygen conditions for the last few centuries [8]. This ecosystem is also the most productive in the world in terms of fish and one that is subject to large interannual to multi-decadal changes in ocean physics and ecosystem productivity and structure [9].

Eastern boundary upwelling systems (EBUS), i.e., Benguela, California, Canary and the Humboldt Current systems support two heavily exploited fish resources, anchovy (the genus Engraulis) and sardine (the genera Sardinops and Sardina). Observations over the past several decades show that these species varied on multi-decadal time scales and often in an out of phase relationship [10]-[15] and the literature describes these periods of varying abundances as anchovy or sardine 'regimes' [10], [13].

A number of hypotheses have been suggested for these fluctuations in anchovies and sardines including sea-surface temperature (SST), food availability and prey size spectra (e.g. [12] and [15]). In EBUS anchovy and sardine are associated with relatively cold and warm conditions, respectively [10], [12], [16]. Cool conditions are accompanied by more nutrients in the euphotic layer and the development of large phytoplankton (e.g. chain-forming centric diatoms) and zooplankton (e.g. large copepods and euphausiids) [17]. Such conditions are predicted to favor anchovy that feed primarily by direct biting on large zooplankton [18]-[19]. In contrast warmer conditions are associated with lower nutrient concentration in the near-surface layer that favor the development of smaller phytoplankton and zooplankton [17] that sardines can more efficiently filter-feed [15].

This relatively simple scheme might indeed explain the anchovy/sardine fluctuations observed during the last decades in the southeastern tropical Pacific off Peru. Historical data show that anchovy ( Engraulis ringens) was particularly abundant during the relatively cold periods that occurred during the 1960s to the early 1970s, was replaced by the sardine ( Sardinops sagax) during the warmer years after, which in turn collapsed during the late 1990s and has been virtually absent since the early 2000s, with a return to anchovy abundance [13]. However, the sardine is tolerant of a variety of oceanographic conditions including large temperature ranges (∼9-25°C), and can associate with diverse water masses [20]-[23]. Temperature alone cannot therefore explain the fluctuations in sardine recruitment and distribution [20], [21], [24], [25]. Furthermore, it has also been demonstrated that the sardine can forage on macrozooplankton, with euphausiids constituting more than one third of sardine prey carbon content [26]. If sardine can physiologically tolerate relatively low temperatures and forage on both the large and small sizes of zooplankton, why did it collapse in the late 1990s when (large) prey were abundant and temperature was well within its range of tolerance? Sardine overfishing during the late 1990s was probably an important factor [11], [21], [27] but probably not the unique one. Indeed, analysis of scale or bone remains in sediment cores, show decadal and multi-decadal fluctuations of anchovy and sardine biomass before the development of industrial fishing [8]. Also, during the last two centuries, only two multi-decadal periods of expansion of sardine occurred off Peru [8]. Moreover, periods of anchovy and sardine coexistence have been observed in the past [8], [28]-[29] and in other EBUS [25], [29]. Thus, there may be other parameters than sea-surface temperature, food availability and prey size-spectra that explain pelagic fish fluctuations off Peru.

Here we propose that the need to breathe may be the critical property determining ecosystem structure in the productive waters off Peru. Effectively, fish need sufficient amounts of both food and oxygen, but the latter might be more difficult to obtain than the former [30]. EBUS are associated with oxygen minimum zones (OMZs) where subsurface layers are low in dissolved oxygen (DO). These OMZs, have notable effects on the distribution of marine organisms [1], [7], [31]-[36]. Coastal upwelling then transports low and unsaturated concentrations of DO to the surface [37]. Reduced oxygen can impact fish in at least two ways: (i) by directly affecting fish breathing in the layer where they are distributed, (ii) by compressing their vertical habitat.

We propose that the spatial and temporal dynamics of near-surface DO, percentage of dissolved-oxygen saturation (DO sat), and oxycline depth (Z 2 mL/L) and the impact and regulate anchovy, sardine distribution and abundance in the coastal southeastern tropical Pacific. The impact of oxygen also depends on the food web structure and fish energetic need to efficiently forage. We use a comprehensive fisheries oceanography dataset, collected by the Instituto del Mar del Peru (IMARPE), to investigate the effect of oxygen on fish at three scales: (i) decadally through fluctuations in fish landings (1964-2008), using virtual population analysis (VPA) biomass (1964-2006) and biomass estimated acoustically (1983-2008); (ii) cross-shore fish biomass distributions; and (iii) the small scale patterns of fish acoustic biomass (1983-2005). The results illustrate the critical role of oxygen on fish distribution from the perspective of the two primary fish survival requirements, the need to eat and the need to breathe. We show that oxygen fills a current gap in our understanding of pelagic fish fluctuations and explains the recent sardine collapse leading us to propose a conceptual model of spatiotemporal variations in pelagic fish populations off Peru at multiple scales.

Results

Temporal patterns

DO, DO sat and Z 2 mL/L presented similar decadal patterns with low values in the 1960s followed by an increase during the 1970s, reaching a maximum during the 1980s, followed by a decrease during the 1990s-2000s ( Fig. 1A,B,C). Anchovy catch and biomass (estimated by both VPA and acoustic) were higher during periods of lower DO and DO sat and shallower Z 2 mL/L ( Fig. 1D). Anchovy and oxygen showed significant ( P<0.001) negative correlation ( Fig. 2; see Figure S1 for cross correlation preformed on unsmoothed series). The peak in cross-correlation occurred at a lag of 0 years, except for anchovy catches and VPA-estimated biomass and DO where it occurred at a lag of 1 year ( Fig. 2). In contrast, sardine catch and biomass ( Fig. 1E) were in-phase with the oxygen time series; sardine being abundant when DO and DO sat were higher than ∼4.3 mL L −1 and ∼80%, respectively and Z 2 mL/L deeper than ∼40 m ( Fig. 1). Note at this scale that the range of variation of oxygen variables is lower than at other scales, which is logical since we are averaging data over a large area (both along-shore and cross-shore). The in-phase relationships were highly significant ( P<0.001; Figs. 2 and S1) and cross-correlation analyses peaked at a lag of 0 year in all cases, except between sardine caches and DO where the peak occurred at +2 years.

Cross-shore patterns

The mean (1983-2005) cross-shore evolution of DO, DO sat, Z 2 mL/L and pelagic fish relative biomass in the study region is shown in Figure 3A. The upwelling of highly remineralized, suboxic water is evident close to the coast as relatively low DO (∼2.5 mL L −1) and DO sat (∼40%), and shallow oxycline depth (Z 2 mL/L = ∼15 m). DO and DO sat show a sharp linear increase in the offshore domain reaching values of ∼5 mL L −1 and ∼95%, respectively, at 100 km from the coast. DO shows a near-constant value of 5.1 mL L −1, corresponding to the 100% saturation level, in offshore waters (>150 km from the coast). As with other studies (e.g. [38]), Z 2 mL/L rapidly deepened from ∼15 m at the coast to ∼60 m at 100 km, then slowly deepened to 80 m at 400 km from the coast.

Anchovy abundance was inversely correlated with oxygen showing a maximum close to the coast in the poorly-oxygenated near-surface water, decreasing sharply to a distance of ∼30 km and then gently after ( Fig. 3A). Over the study period the anchovy distribution was typically restricted to within 150 km from the coast and 50% of the anchovy biomass was associated with DO values lower than ∼3.5 mL L −1 which corresponds to saturation levels <65% and an oxycline depth shallower than ∼30 m. In contrast, sardine biomass displayed a minimum next to the coast and increased offshore reaching a maximum at ∼80-100 km from the coast where near-surface water masses are relatively well-oxygenated, with DO and DO sat values of ∼4.9 mL L −1 and ∼90% respectively, and the oxycline is deeper than ∼60 m. Further from shore sardine biomass progressively decreased. Sardine were preferentially (>80% of their cumulative biomass) distributed where DO and DO sat were higher than ∼4.4 mL L −1 and 80% respectively, and Z 2 mL/L deeper than ∼40 m.

Mean cross-shore patterns of DO, DO sat and Z 2 mL/L ( Fig. 3B) also show evidence of decadal variations. The mean position by decade of DO, DO sat and Z 2 mL/L isolines equal to 4.4 mL L −1, 80% and 40 m, respectively, is shown in Figure 3B. Highly-oxygenated surface waters (DO>4.4 mL L −1, DOsat>80%, Z 2 mL/L>40 m) were located further than 55 km from the coast during the 1960s and moved progressively closer to the coast to reach minimum distances in the 1980s. After the 1980s the trends reversed and these waters retracted away from the coast during the 1990s (distances similar to the 1970s) and the 2000s but they have yet to reach the maximum values observed during the 1960s. These changes are associated with approaches and retreats of warmer, higher salinity (and higher oxygen) subtropical surface waters or inversely, the coastal expansion and contraction of the cooler, lower salinity coastal upwelling waters.

Local scale

General additive models (GAMs) show that DO, DO sat and Z 2 mL/L were significantly correlated ( p = 0.000) with fish biomass ( Fig. 4). The effect of oxygen on anchovy biomass was weaker than for sardine; however anchovy was more abundant when DO, DO sat and Z 2 mL/L were lower than ∼4.5 mL L −1, ∼85% and ∼40 m, respectively. Sardine show a strong negative effect of DO, DO sat and Z 2 mL/L, in particular when these decreased below ∼3.8 mL L −1, ∼60-70% and ∼25 m, respectively.

Discussion

The results show that fish distribution and abundance in the coastal southeastern tropical Pacific are correlated to near-surface oxygen concentration/saturation and oxycline depth over a wide variety of scales. Further anchovy and sardine do not respond in a similar manner, anchovy shows an out-of-phase relationship compared to sardine. During the 1960s-early 1970s and the l990s-2000s, when DO and DO sat were low and Z 2 mL/L shallow, anchovy was abundant but sardine did not proliferate. The opposite occurred during the late 1970s and 1980s when sardine exploded. It appears as if the turning point is when DO, DO sat and Z 2 mL/L are greater or below ∼4 mL L −1, ∼70-80% and ∼25-35 m, respectively. Fish need oxygen to breathe, and getting oxygen inside their bodies is expensive energetically and more difficult at lower concentrations [30] but why such differences between species?

Larger fish need more oxygen

Anchovy and sardine are gregarious fish and obligate ram ventilators. Oxygen supply per body size decreases as fish size/weight increases [30]. Sardine are larger fish than anchovy. Also the comparison of respiration rates between sardine and anchovy indicate a higher demand for sardine than for anchovy ( Engraulis capensis) [39]. Finally [35], [40] showed that anchovy does not seem affected by a very shallow oxycline (<10 m) while sardine avoid such areas. Not only can the smaller anchovy survive in a very shallow oxycline but escapes predation by larger fish in doing so.

Oxygen consumption, trophic structure and habitat compression

Oxygen demand also depends on the quality and quantity of food [30]. The Peruvian anchovy gets most of its energy by visual selection and direct biting on macrozooplankton [19]. Filter-feeding is very expensive metabolically relative to biting for anchovies [18], [39]. Zooplankton are very likely concentrated by a shallow oxycline [9] favoring anchovy bio-energetics. In sharp contrast, filter-feeding is energetically much cheaper for sardines [39], and the reason they might require more vertical habitat. These conclusions are supported by measurements of zooplankton size-structure which also exhibited multi-decadal fluctuations [41]. Euphausiids and large copepods were in-phase with anchovy peaks while sardine was more abundant when small zooplankton dominated [41]. During periods of high euphausiids and anchovy abundance the oxygenated vertical habitat was restricted to a very shallow layer concentrating the prey near the surface enhancing anchovy foraging (see [34]). Off Peru, ∼79% of the macrozooplankton, in particular euphausiids, perform vertical migration and distribute below the oxycline during the day [42]. During the night these organisms concentrate in the surface layer where they are foraged by anchovy, that adapt their foraging strategy (e.g. feeding time) to prey composition and concentration [19], [41]. The shallower the oxycline, the more concentrated the prey.

The results lead us to suggest the following conceptual model ( Fig. 5). During the 1960s nutrient supply to the surface was enhanced by vertical displacement of isotherms upward, favoring large phytoplankton and zooplankton [43]. The vertical displacements reduced oxygen concentration and vertical habitat in the near-coastal regions, a condition that favored the anchovy which feeds on large zooplankton, tolerates low oxygen conditions and very narrow oxygenated habitats [35], [40]. In the early 1970s, climate changed, isotherms deepened and the system shifted toward less macrozooplankton [41], higher DO and a deeper oxycline. The anchovy populations dropped and sardine populations were favored. Anchovy collapse has been attributed to a combination of overfishing, an El Niño event and the decadal shift towards less productive conditions [14], [21]. The growth of sardines is linked here to a deeper and more oxygenated habitat and higher concentrations of small zooplankton that can be effectively harvested by filter feeding.

The 1980s were optimum for sardine: moderate productivity, greater concentrations of small zooplankton, more oxygen-saturated waters close to the coast, and a greater vertical oxygenated habitat. In contrast, conditions were less favorable for anchovy because of a reduction in nutrient supply, a narrow coastal habitat of upwelling/isotherm shoaling, increased predation, and a decrease in macrozooplankton [9], [21], [23], [41]. During the 1990s the climate reverted to conditions similar to the 1960s, early 1970s and led to a decrease/increase in sardine/anchovy populations. By the early 2000s the ecosystem was in a full anchovy regime [13], [22]. The system returned to one of high macrozooplankton abundance and dominance [41], [42], and low oxygen (both horizontally and vertically). The crash of the sardine population can be attributed to the synergetic effect of trophic structure and oxygen; these environmental effects were most likely aggravated by overfishing [11], [21], [27]. Prey was dominated by large zooplankton forcing sardine to shift toward a more energetically expensive direct biting, which became limiting due to changes in oxygen availability and vertical habitat. Sardine could not approach the coast and feed in the rich coastal habitat and slowly disappeared. Finally we can note that paleoecological studies show that sardine persistence was greater and variability reduced in Northern Chile relative to Peru [8]. We interpret this to be that oxygen is less regulating for sardines to the south. The OMZ is deeper off Chile [38] and the colder surface water can also contain more dissolved oxygen. In support of our findings it has been postulated that the sardine decline in the northern Benguela Current system was related to oxygen decrease in the spawning areas on the Namibian shelf [32], [44].

Toward a 3D heuristic habitat-based hypothesis

The habitat-based hypothesis [21], [35], [40] suggests that spatial and temporal dynamics in habitat ultimately regulate fish distributions. For example, the anchovy habitat is restricted to the cold, upwelled coastal waters on a variety of scales [21], [23], [40]. Anchovy population dynamics has been shown to depend on the extension-contraction of these nutrient-rich waters, however, the habitat-based hypothesis did not account for why the sardine was restricted from nearshore waters and collapsed in the late 1990s. Oxygen adds the missing link and explains why sardine habitat moved further offshore where the retention of eggs and larvae is less efficient [45] and the quantity of food drops, weakening larval feeding success and survival. A large offshore low oxygen habitat is ideal for anchovy ( Fig. 5C), allowing it access to the high concentrations of macrozooplankton at the shelf break [42]. Competition for food and predation on fish eggs, larvae and adults is reduced by the 'expulsion' of species that cannot survive in low oxygen conditions. Sardine benefit from a more oxygenated-deeper habitat ( Fig. 5C). During these multi-decadal periods productivity is reduced but it is still high relative to other ecosystems and allows sardine accessing to coastal areas of enhanced productivity.

In conclusion, oxygen appears to provide the missing link needed to explain pelagic fish spatiotemporal dynamics and regimes in the southeastern tropical Pacific. Does habitat compression by oxygen also lead to the incredible production of fish observed off Peru relative to the other EBUS [9]? Is it because the prey are concentrated leading to an increase in fish carrying capacity or are the fish themselves concentrated making them more vulnerable to fishing? The former is more likely but these and other questions about oxygen and ecosystems remain and answers will be needed sooner rather than later given reports of expanding OMZs and eutrophication driven decreases in oxygen [5]-[6], [46]. How these changes will affect EBUS, which sustain ∼20% of worldwide fish harvests [47] remains uncertain.

Materials and Methods

This study focuses on the coastal southeastern tropical Pacific between 7°S and 18°S. The area is characterized by low oxygen, cold and fresh water in the coastal surface layers and higher oxygen, warm and salty subtropical surface water further offshore [23], [38].

Environmental data

An archive of ∼15 000 vertical profiles of temperature, salinity, and DO has been assembled for the region between 7°S and 18°S, an area where the OMZ is homogeneous [38], and from the Peruvian coast to 400 km offshore. Temperature and salinity were required to compute DO sat. These profiles were collected between 1961 and 2008 and obtained from the IMARPE and the World Ocean Database (WOD09, [48]). We have used both point-sampled stations (Nansen and Niskin bottles) and continuously sampled traces from conductivity-temperature-depth probes and profiling floats.

First, casts were interpolated onto 55 standard depth levels distributed between the surface and 1000 m depth, using an algorithm based on [49]. The vertical profiles do not properly identify "surface data" because the sample closest to the surface is in average located from 5-10 m depth. The near-surface reference depth was thus set at 10 m. The percentage saturation was calculated from DO sat = (DO/DO′)×100, where DO′ is the solubility of oxygen at the in situ temperature and salinity measured at 10 m depth.

Second, for each interpolated profile, the oxycline depth was defined as the depth where the DO equals 2 mL L −1 (Z 2 mL/L). A linear interpolation between standard levels is used to estimate the exact depth at which the value of 2 mL L −1 is reached. Note that [35] showed that the lower oxycline depth (or the top of the OMZ) corresponds to a DO of ∼0.8 mL L −1 (Z 0.8 mL/L). This value was estimated taking into account all organisms (fish, zooplankton and gelatinous), but epipelagic fish, which are the focus of this study, are most often found when DO is higher than 1.5-2 mL L −1 (e.g. [32]-[33]). As a result we used a DO value of 2 mL L −1 as a proxy of the oxycline depth taking into account that the oxycline is sharp off Peru and that Z 2 mL/L and Z 0.8 mL/L are significantly correlated (p = 0.000, R ²  = 0.91).

In order to study the mean large-scale interannual variations of oxygen parameters we focused on the stations located between the coast and 200 km offshore. From the ∼11 000 remaining values, we computed annual averages between 1961 and 2008. The annual time series were further smoothed using a non-parametric spline model with a degree of freedom ( df) ranging from 4 to 5 ( Fig. 1A-C) minimizing the GCV. Four-years moving average are also indicated in Figure 1A-C.

Cross-shore variations of oxygen properties were also investigated by computing mean profiles between the coast and 400 km offshore for each decade from the 1960s to 2000s. These mean cross-shore profiles were also smoothed using a non-parametric spline model (e.g. Fig. 3A). We determined the relative position from the coast of the 4.4 mL L −1, 80% and 40 m isolines from the filtered decadal cross-shore profiles ( Fig. 3B).

Finally, to study fish-oxygen interactions at a local scale we used environmental information collected during acoustic surveys. DO and Z 2 mL/L data were interpolated using the natural neighbor method and averaged at the scale of acoustic data. Then corresponding data of salinity and temperature were used to calculate DO sat.

Fish data

Anchovy and sardine landings (1964-2008) and biomass estimates from virtual population analysis (VPA) series (1964-2006) were provided by IMARPE. Acoustic fish biomass data were collected from 1983 to 2008 by IMARPE during 49 surveys performed on a variety of research vessels (see [22]). These surveys consisted of parallel cross-shore transects of ∼100 nm long, with a ∼15 nm spacing. Simrad (Kongsberg Maritime AS, Norway) scientific echosounders working at distinct frequencies were used to estimate biomass abundances (see [22]). Extensive midwater-trawl sampling accompanied the acoustic surveys for species identification and biological samples. Nautical-area-backscattering coefficients were recorded in each georeferenced elementary distance sampling unit (EDSU) equal to one or two nautical miles depending on the sample period. Identification of echoes was accomplished using metrics of the echoes and the catches from associated fishing trawls. Biomass estimates based on the acoustic backscatter for each species were carried out by IMARPE for each survey (see [22]).

Data analysis

The effect of DO, DO sat and/or Z 2 mL/L on pelagic fish was studied in three ways: (i) large temporal scale to study the decadal patterns between 1964 and 2008; (ii) cross-shore patterns; and (iii) small scale patterns (one EDSU) using data from the 44 acoustic surveys performed between 1983 and 2005. Different analyses were performed at each scale.

Large scale

To remove high frequency variability (which is addressed at the local scale) and focus on decadal trends, annual time series of near-surface DO sat, Z 2 mL/L, fish landings, and fish VPA and acoustic biomass estimates were smoothed using a non-parametric spline model ( df ranged between 4 and 5). The resultant filtered time series were cross-correlated to ascertain whether the time series are in-phase, unrelated or alternate in phase. To test for the robustness of these cross correlations we performed them with the unsmoothed data and obtained similar results ( Fig. S1). The cross-correlations significance levels were not corrected for possible biases due to temporal autocorrelation. Autocorrelation should reduce the degrees of freedom for the cross-correlation significance tests. However, the high cross-correlations for lags around 0 suggest that the series were either in or out of phase ( Figs. 2 and S1). A very small p-value (p = 0.001) for significance was chosen ( Fig. 2).

Cross-shore profiles

In order to study the mean cross shore variations from the coast to 400 km offshore, DO, DO sat, Z 2 mL/L, and acoustic fish biomass estimates were smoothed using a non-parametric spline model. Decadal changes in the cross-shore profiles of ambient parameters (DO, DO sat, and Z 2 mL/L) were also examined by applying the same procedure on decadal datasets between the 1960s to the 2000s. For each decade the distance from shore where surface DO, DO sat and Z 2 mL/L are equal to 4.4 mL L −1, 80% and 40 m, respectively was calculated.

Local scale

At the EDSU scale, we used Generalized Additive Models (GAMs) to test the effect of DO, DO sat and Z 2 mL/L on local fish acoustic biomass. Fish acoustic data are characterized by a large number of zeros (86% of our dataset). This feature generates a non-Gaussian distribution of the data which limits the use of GAMs. To avoid such limitation we modeled the GAMs applying the Tweedie versatile family distribution [50], which are commonly used to represent distributions that have a non-zero probability for the zero value.

Supporting Information

Time-lagged cross-correlations in year performed from unsmoothed data between anchovy and sardine catches, VPA-estimated and acoustic biomasses, and DO, DOsat and Z2 mL L−1 at different time lags. Values above (below, respectively) the top (bottom) dashed lines are significant at p = 0.01.
https://doi.org/10.1371/journal.pone.0029558.s001
(TIF)

Acknowledgments

We thank P. Lopez for helping to prepare the figures.

Author Contributions

Conceived and designed the experiments: AB. Performed the experiments: AB AC SP JL. Analyzed the data: AB AC SP JL MG FM. Contributed reagents/materials/analysis tools: AB AC SP JL MG FM FPC. Wrote the paper: AB AC FPC.

References

1. 11. Csirke J, Guevara-Carrasco R, Cárdenas G, Ñiquen M, Chipollini A (1996) State of the resources anchoveta (Engraulis ringens) and sardine (Sardinops sagax) in early 1994 and perspective for fishing in Peru with special emphasis on the Centre and North regions of the Peruvian coast. Bol Inst Mar Peru 15: 1-23.

2. 15. van der Lingen CD, Hutchings L, Field JG (2006) Comparative trophodynamics of anchovy Engraulis encrasicolus and sardine Sardinops sagax in the southern Benguela: are species alternations between small pelagic fish trophodynamically mediated? Afr J Mar Sci 28: 465-477.

3. 18. James AG, Probyn T (1989) The relationship between respiration rate, swimming speed and feeding behaviour in the Cape anchovy Engraulis capensis Gilchrist. J Exp Mar Biol Ecol 31: 81-100.

4. 19. Espinoza P, Bertrand A (2008) Revisiting Peruvian anchovy (Engraulis ringens) trophodynamics provides a new vision of the Humboldt Current system. Prog Oceanogr 79: 215-227.

5. 22. Gutierrez M, Swartzman G, Bertrand A, Bertrand S (2007) Anchovy (Engraulis ringens) and sardine (Sardinops sagax) spatial dynamics and aggregation patterns in the Humboldt Current ecosystem, Peru, from 1983-2003. Fish Oceanogr 16: 155-168.

6. 24. Serra R, Cury P, Roy C (1998) The Recruitment of the Chilean Sardine (Sardinops sagax) and the "Optimal Environmental Window. In: Durand MH, Cury P, Mendelssohn R, Roy C, Bakun A, Pauly D, editors. Global versus local changes in upwelling systems. ORSTOM, Paris. pp. 267-274.

7. 26. Espinoza P, Bertrand A, van der Lingen CD, Garrido S, De Mendiola BJ (2009) Diet of sardine (Sardinops sagax) in the northern Humboldt Current system and comparison with the diets of clupeoids in this and other eastern boundary upwelling systems. Prog Oceanogr 83: 242-250.

8. 27. FAO (2009) The state of world fisheries and aquaculture 2008. FAO Fisheries and Aquaculture Department, Rome.

9. 29. Field DB, Baumgartner TR, Ferreira V, Gutiérrez D, Lozano-Montes H, et al. (2009) Chapter 4. Variability from scales in marine sediments and other historical records. In: Checkley DMJ, Roy C, Alheit J, Oozeki Y, editors. Climate Change and Small Pelagic Fish. Cambridge University. pp. 45-63.

10. 30. Pauly D (2010) Gasping fish and panting squids: oxygen, temperature and the growth of water-breathing animals. (Excellence in ecology. Book 22. International Ecology Institute, Oldendorf/Luhe).

11. 48. Garcia HE, Locarnini RA, Boyer TP, Antonov JI, Baranova OK, et al. (2010) World Ocean Atlas 2009, Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization, and Oxygen Saturation. (NOAA Atlas NESDIS 70, U.S. Government Printing Office, Washington, D.C.).

# data[].attributes.attachment_link.title
Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific

# data[].attributes.attachment_link.description
Background In the southeastern tropical Pacific anchovy (Engraulis ringens) and sardine (Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature.

# data[].attributes.headline
Ways to help kids cope with - and help combat - climate change

# data[].attributes.subject
Ways to help kids cope with - and help combat - climate change

# data[].attributes.attachment_link.readable_text
News of the coming environmental collapse has broken with unnerving regularity, and with each new tidbit - the Arctic Ocean has lost 95 percent of its oldest ice, global warming is making already-dramatic natural disasters more fierce, Europe's climate disaster is growing, and October's news that we have 12 years to limit climate-change catastrophe - my anxiety about the future grows.

But I'm far more worried about our kids.

They hear about our planet's rising temperature and rapidly melting ice, giant islands of floating plastic, and the more than 16,000 animals threatened with extinction almost as much as we do, and they're feeling the impact.

Conversations about threats to the environment and the plight of endangered species are not new for kids. And in Seattle, where I live, environmental stewardship and eco-consciousness are de rigueur: My children have been learning about conservation since preschool. Reusable bags, water bottles and compost bins in homes and public places have been part of the fabric of our lives for years. Children here can participate in beach cleanups with their classes; in my kids' school, they separate compost from recyclables and garbage - last month, they even weighed it classroom by classroom to measure their sorting success.
[Here's what to keep in mind when talking to kids about tough subjects]
But the tone has shifted. The feeling is more dire. I don't know what kids are supposed to do with the sobering fact that their planet is changing for the worse.

According to Laura Kastner, a clinical psychologist and professor in the psychology department and the department of psychiatry and behavioral sciences at the University of Washington, the way to teach kids about environmental issues is not by overwhelming them with data or presenting them with projected outcomes they can see no way of changing. It's by being realistic with kids and also teaching them agency and action.

It's what Kastner describes as the "both-and." The idea of first acknowledging that, yes, climate change is happening, and there are things we can do to help. "We really are going to have to deal with this, and there is so much to do, so let's get to work," she said. "We want to be responsible and smart and informed about what's happening, and we want to be hopeful and agentic."

Heather Price, an atmospheric chemist, climate scientist and chemistry instructor at North Seattle College, who has presented climate science to members of Congress, says that whenever she gives a talk about rising temperatures, ocean acidification and mass extinctions, she always spends at least a quarter of her time discussing the areas where scientists see hope and how people are already altering the trajectory. For example, the capacity of renewable energy in the United Kingdom has surpassed that of fossil fuels for the first time, and in the United States, electric car sales were up 81 percent in 2018 over sales in 2017. Price knows the science is depressing. "But," she says, "it's not on the science side where the good things are happening. It's on the mitigation, on the solutions."

It's possible to be straightforward about climate change with our children and protect their emotional well-being. Here are some ways to help children be part of the team that mitigates the impact of climate change, so they don't have to despair over the future.

Don't overdo the news

Kastner recommends news in moderation. Although adults may want to watch and listen to the news, a little goes a long way for children. "There's a difference between being prepared and being overwhelmed, especially for kids," she said. "I don't want them to feel hopeless."

The news cycle can be too much, especially if a child is sensitive. "When you have anxious kids watching the TV or anxious families . . . you literally see an uptick in kids' anxiety," she says. "When parents do doom and gloom and watch TV a lot, they're hurting their children." It's the responsibility of parents and caregivers to regulate their kids' media consumption; they simply do not need to know everything.

Know your child

As in all areas of parenting, it's up to caregivers to assess how much their kid can take. "If you know your child is more anxious than the next kid or has a sensitive temperament, you have to parent differently," Kastner says. "It's not so much about keeping kids away from every bit of information" about rising temperatures and extinction, it's that "you handle it differently. You change the words depending on their age, their sophisticationand what we think they can handle - what they need."

When Price visits middle schools to give climate talks to eighth-grade classes, she engages them with activities tailored for their age. "I take methane and make bubbles and then we light them on fire; we put ice in buckets." With kids, she says, you have to "make it fun and talk about hope, kind of inspire them." These students , she discovered, really like Teslas, "so I talk with them about how by the time they're my age, they're probably going to be driving a car more like a Tesla."

Emphasize agency

At home or in school, parents and educators can pair environmental studies with actionable steps such as having kids organize a challenge to increase the number of students and faculty bringing reusable bottles to school. They can research how many species have thrived under the Endangered Species Act or find a way to compost cafeteria scraps. Inviting children to brainstorm strategies for progress helps energize and give them hope. Families can support an environmental organization, plan a park cleanup or host a bake sale to raise money for habitat preservation of a kid's favorite endangered animal.

"Part of depression," Kastner explains, "is hopelessness and helplessness. . . . When you are agentic, when you are the one to go get the blue tarps [after a hurricane] and hand them out, you're always going to do better than if you're sitting there waiting for the tarps."

Price agrees: "It's all about framing: How am I going to act, what am I going to do?"

Price's mantra is that "action feeds hope feeds action feeds hope. Because without hope, you're not going to have action, without action, you're not going to have hope. They feed each other."

Manage what you can manage

None of us will be able to make a dent in all aspects of climate change on our own, but we can break down the issues into bite-size, manageable pieces. We can explore the many ways in which we can change outcomes, whether that's supporting science and tech to help manage rising sea levels, getting involved in politics to protect those who have to leave flooded land, or helping physically move displaced people.

"Seeing how quickly humans can transition" is what encourages Price. For example, she says, "the price to install solar back in 1977 when Star Wars first came out was $77 per watt, and today, depending in which state you live, it's anywhere from 10 cents to 20 cents per watt." And, in Seattle, because of hydroelectric energy and solar and wind farms, almost no electricity is coming from coal, oil or gas, making it one of the greenest cities for electricity, she says.

And there are young leaders such as 16-year old Greta Thunberg from Sweden, named one of Time magazine's most influential teens of 2018. After grabbing international headlines for striking from school to draw attention to Sweden's unprecedented heat waves and growing struggle with wildfires, she confronted world leaders about global inaction on climate change, telling representatives from the nearly 200 nations gathered at COP24, the 24th Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC): "I've learned you are never too small to make a difference. And if a few children can get headlines all over the world just by not going to school, then imagine what we could all do together if we really wanted to."

We are entering a new environmental era, and parents can guide children through this time by acknowledging that climate changecan be frightening and helping kids take action.

"What's important," Kastner says, "is that parents know how much they matter in this." They aren't sticking their heads in the sand; they know what challenges await their children. But when parents decide "that they're going to plant trees, and they're going to volunteer at the school to do cleanup, and they're going to be activated by this, then their kids are going to do better."

As daunting as climate change might be, we do have a choice about how to use our energy - even worried, anxious energy. We don't have to wait to be rescued. We can show our children that we can choose hope and empowerment. We can be the ones who hand out the blue tarps.
More from Lifestyle: 7 things to keep in mind when talking to kids about tough subjects Park the helicopter, parents. Here's how and why to teach kids to be self-advocates. Kids consume news, but don't know what's real or fake. Here's how parents can help. What does childhood anxiety look like? Probably not what you think.

# data[].attributes.attachment_link.title
Ways to help kids cope with - and help combat - climate change

# data[].attributes.attachment_link.description
News of the coming environmental collapse has broken with unnerving regularity, and with each new tidbit - the Arctic Ocean has lost 95 percent of its oldest ice, global warming is making already-dramatic natural disasters more fierce, Europe's climate disaster is growing, and October's news that we have 12 years to limit climate-change catastrophe - my anxiety about the future grows.

# data[].attributes.attachment_link.description
Yale Climate Connections is a nonpartisan, multimedia service providing daily broadcast radio programming and original web-based reporting, commentary, and analysis on the issue of climate change, one of the greatest challenges and stories confronting modern society.

# data[].attributes.attachment_link.readable_text
Atmospheric rivers commonly begin as warm water storms over the Pacific Ocean, where evaporation creates a high concentration of moisture in the air. Prevailing winds give ARs their distinctive shape, and probably helped give rise to their comparisons to a fire hose, pointed at California.

When ARs are blown over land, the giant streams of moisture they contain cool and condense, causing heavy snow or downpours, depending on the elevation.

The term " Pineapple Express" (not this Pineapple Express) refers to ARs that form in tropical regions of the Pacific, often around Hawaii. These can pound the west coast of North America from California to Canada with intense storms.
But What Makes ARs Different From Other Storms?

Atmospheric rivers are categorized by a unit of measurement called Integrated Water Vapor Transport (IVT). IVT takes into account both the amount of water vapor in the system and the wind that moves it around, making it flow like a, well, giant river in the atmosphere.

For a storm to be classified as an AR, it must reach an IVT threshold of 250 units. An atmospheric river with IVT of 1,000 or more is considered an " extreme" AR.
Are Atmospheric Rivers Good or Bad?

Atmospheric rivers produce up to 50 percent of California's precipitation annually and 65 percent seasonally. According to Ralph, the state gets one to two dozen AR storms per year. When we have fewer, we get...yes, that would be drought.

"Atmospheric rivers make or break our water year in California," Ralph says.

However, when we get too much AR storm activity, look out.

A typical atmospheric river event lasts about a day. Problems begin when they last longer in duration or occur back-to-back. This can lead to major hazards like flooding, mudslides or ash flow in the aftermath of wildfires.

Research suggests that atmospheric rivers contributed to the collapse of both spillways at Oroville Dam in February of 2017.

ARs were also undoubtedly behind the worst floods in California's history, when the state capital of Sacramento was inundated during the winter of 1861-62.
Atmospheric rivers don't just affect California. Here's a quick Canadian take on them:
Should I Be Worried?

Though ARs don't get assigned names, like hurricanes, they are the "900-pound gorilla" of West Coast weather.

"For the West Coast, they are really our big storms," says Julie Kalansky, operations manager at CW3E.

The problem in the past has been that atmospheric rivers have been hard to forecast. While satellites provide some information, ARs are relatively low-lying storm systems, which means they're often obscured from space by higher altitude clouds.

In recent years, Ralph and his colleagues at the Scripps Institution of Oceanography, the Air Force and National Oceanic and Atmospheric Administration (NOAA), have been working to better understand AR phenomena. They're using techniques like flying aircraft along the path of atmospheric rivers and dropping weather sensors called "dropsondes" directly into them from above.

With the advancements in tracking, CW3E is in the process of developing a five-point scale to categorize atmospheric rivers like those used for other tropical storms and tornadoes.
How Is Climate Change Affecting ARs?

Ralph says there is still more research to be done, but atmospheric rivers are increasingly appearing in climate models. He notes that the recently-released National Climate Assessment added ARs to the list of extreme weather threats.

One thing appears to be clear: the warmer the atmosphere, the more moisture an atmospheric river can contain.

Ralph says this may not increase the frequency of atmospheric rivers in the future, but will make them more intense.

"They will be stronger," Ralph says, "That's pretty much a consensus in the [scientific] community."
KQED Science Editor Craig Miller contributed to this post.

# data[].attributes.attachment_link.title
Rivers in the Sky: What You Need to Know About Atmospheric River Storms

# data[].attributes.attachment_link.description
Atmospheric rivers commonly begin as warm water storms over the Pacific Ocean, where evaporation creates a high concentration of moisture in the air. Prevailing winds give ARs their distinctive shape, and probably helped give rise to their comparisons to a fire hose, pointed at California.

# data[].attributes.headline
JPL: Wind, Warm Water Revved Up Melting Antarctic Glaciers

# data[].attributes.subject
JPL: Wind, Warm Water Revved Up Melting Antarctic Glaciers

# data[].attributes.attachment_link.readable_text
A NASA study has located the Antarctic glaciers that accelerated the fastest between 2008 and 2014 and finds that the most likely cause of their speedup is an observed influx of warm water into the bay where they're located.

The water was only 1 to 2 degrees Fahrenheit (0.5 to 1 degree Celsius) warmer than usual water temperatures in the area, but it increased the glaciers' flow speeds by up to 25 percent and multiplied the rate of glacial ice loss by three to five times -- from 7 to 10 feet of thinning per year (2 to 3 meters) up to 33 feet per year (10 meters).

Researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, found that the warmer water was driven into the area by winds associated with two global climate patterns: La Niña and the less-known Southern Annular Mode, which involves a change in location of the belt of winds that encircles Antarctica. The glaciers' acceleration lasted from mid-2008 to 2012. After that, they slowed down but have continued to flow faster than they did before the warm water arrived.

The study is published in the journal Earth and Planetary Science Letters.

The four glaciers are in Marguerite Bay on the western side of the Antarctic Peninsula. Before 2008, their flow rates and rates of thinning (a measure of ice loss) had been stable for almost two decades -- since the Wordie Ice Shelf in front of the glaciers collapsed in about 1989. The collapse broke off almost all of the floating portions of the glaciers, leaving the parts that are grounded on bedrock.

"Grounded ice is a major concern for sea level rise, because it hasn't contributed to sea level yet," said the new study's lead author, Catherine Walker of JPL. "Floating ice has already made its contribution to the sea level."

After two decades of relative stability, the magnitude of the glaciers' acceleration was unexpected. Walker and coauthor Alex Gardner of JPL discovered the change by examining new maps of glacial velocities for all Antarctic glaciers, created this year by Gardner and colleagues. The maps were developed by analyzing changes in Landsat satellite images from year to year. Previous data sets have either given a one-year "snapshot" of velocities, focused on a different location, or averaged rates of change over much larger areas of Antarctica, obscuring velocity changes over time and the behavior of individual glaciers. "I don't think anyone could have seen this before these new maps were developed," Walker said.

To find out what caused the speedup, Walker and Gardner checked air temperatures over the bay and saw that, though they had generally warmed over past decades, they hadn't spiked markedly in 2008 to 2012.

Water temperatures were a different story. A long-term data set from the nearby U.S. Antarctic Program's Palmer Station showed that warmer water first appeared in the bay in 2008, peaked in 2009, and stayed there almost nonstop through 2011. Using an analysis of winds in the area from the U.S. ECCO (Estimating the Circulation and Climate of the Ocean) project, Walker and Gardner showed that northwesterly winds allowed this warmer water to well up from the deep ocean onto the continental shelf in front of Marguerite Bay. Currents then carried the warm water into the bay and up to the fronts of the glaciers.

While the warm water was in the bay, there was a moderately strong La Niña event, and the belt of winds circling Antarctica was closer to the continent rather than farther north -- a condition known as the positive phase of the Southern Annular Mode (SAM). The combination of these two climate patterns was responsible for the northwesterly winds along the western side of the Antarctic Peninsula.

The speed at which the Marguerite Bay glaciers responded to a relatively small increase in ocean temperature was startling, Walker said. "We detected the warmest water first in January 2009, and by November the glaciers were already losing ice at a rate of eight meters [25 feet] per year in thickness."

Walker noted that while these glaciers accelerated during a La Niña event, the nearby Pine Island Glacier, one of West Antarctica's fastest-moving glaciers, melts faster during El Niños -- the opposite climate pattern. She said, "This alternating response to global atmospheric patterns underscores the need to improve our understanding of the links between global climate and changes in the polar oceans."
News Media Contact
Alan Buis
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0474
Alan.Buis@jpl.nasa.gov

Written by Carol Rasmussen
NASA's Earth Science News Team

2017-244

# data[].attributes.attachment_link.title
Wind, Warm Water Revved Up Melting Antarctic Glaciers

# data[].attributes.attachment_link.description
A NASA study has located the Antarctic glaciers that accelerated the fastest between 2008 and 2014 and finds that the most likely cause of their speedup is an observed influx of warm water into the bay where they're located.

# data[].attributes.body
California Drought Images

# data[].attributes.attachment_link.title
California drought: then and now - The Boston Globe

# data[].attributes.attachment_link.description
Getty Images photographer Justin Sullivan documented California's severe drought conditions in 2014 and recently returned to the same places to compare the drastic change after the state's exceptionally wet winter. Governor Jerry Brown has ended the state's water emergency status in all but four counties.

# data[].attributes.headline
California Drought: Impacts and Solutions

# data[].attributes.subject
California Drought: Impacts and Solutions

# data[].attributes.attachment_link.readable_text
For the most recent data on the California drought follow the links through the thumbnails below:

With the end of the statewide hydrologic drought from 2011 to 2017, the Pacific Institute Drought Response Team is no longer providing monthly drought updates. We will continue to work toward sustainable water solutions in California and beyond. Continue to follow our work onwww.pacinst.org.

# data[].attributes.attachment_link.description
For the most recent data on the California drought follow the links through the thumbnails below: With the end of the statewide hydrologic drought from 2011 to 2017, the Pacific Institute Drought Response Team is no longer providing monthly drought updates. We will continue to work toward sustainable water solutions in California and beyond.

# data[].attributes.body
Melting increase over the last 40 years

# data[].attributes.attachment_link.readable_text
NOAA GFDL Climate Research Highlights Image Gallery

The Shrinking Arctic Ice Cap

Return to the main NOAA GFDL Climate
Research Highlights web page

contacts:

GFDL scientist contacts for this topic:
Michael Winton, NOAA/GFDL
Keith Dixon, NOAA/GFDL

GFDL Communications Officer: Maria Setzer, NOAA/GFDL

Animations and graphics developed by: Remik Ziemlinski and Keith Dixon

Contact information (email, phone numbers) can be found for these people by entering their names into the NOAA Staff Directory.

The materials presented here help illustrate some of the key research results that GFDL scientists have reported on recently. These graphics are considered to be in the public domain, and thus can be downloaded freely. We do request that if these images are used in publications or media broadcasts credit be given to " NOAA Geophysical Fluid Dynamics Laboratory" or at least " NOAA GFDL ".

2-D Graphics and Maps

ABOVE: 314 x 681 png [87KB]Also available in the following form:

figure caption:
Sea ice concentrations simulated by the GFDL CM2.1 global coupled climate model averaged over August, September and October (the months when Arctic sea ice concentrations generally are at a minimum). Three years (1885, 1985 & 2085) are shown to illustrate the model-simulated trend. A dramatic reduction of summertime sea ice is projected, with the rate of decrease being greatest during the 21st century portion. The colors range from dark blue (ice free) to white (100% sea ice covered).

ABOVE: 314 x 681 png [87KB]

Also available in the following form:

figure caption
Same as for figure directly above.

ABOVE: 630 x 429 png [40KB]

Also available as

figure caption
Summertime Arctic-wide sea ice extent simulated by the GFDL CM2.1 model for the historical period 1860 to 2000 and projected for the 21st century following the SRES A1B emissions scenario. Sea ice extent values are normalized (scaled) so that the average for years 1981 to 2000 is equal to 100%. Totally ice free summer conditions would equal 0%.

Animations and Movies

Animations of the type indicated by the picture above are available in three different sizes.

Select an icon below to access the animation described to its right. In many cases we provide multiple versions of an animation, including a version using the mpg-4 format (well-suited for Windows Media Player viewing) and another in .mov format that is well-suited for viewing with QuickTime player. (Clicking the picture above will direct you to the smallest animation in mpg-4 format.)

1920 x 1080 resolution, .mov format, 240 frames total, 40 seconds at 6 fps [3.7MB]
animation description
The globe on the right side of the animation depicts the sea ice concentration simulated by the GFDL CM2.1 global coupled climate model averaged over August, September and October of each year (the months of the year when Northern Hemisphere sea ice concentrations generally are at a minimum). Sea ice concentration is a measure of how much of the area is covered by sea ice, and is shown here for CM2.1 in part because it looks most like what a satellite sees. The colors on the globe range from dark blue (ice free) to white (100 percent ice covered).

The graph on the right side shows how the Northern Hemisphere summer sea ice extent varies over time in this model simulation. The thick tan curve extends from the start of the simulation to the year shown on the globe. (The frame displayed above the right was taken from year 2040.) A value of 1.0 on the vertical axis corresponds to the average Arctic sea ice extent the model simulated for August through October during the twenty year period 1981 to 2000. A year with a value of 1.4 indicates that 40% more of the model's Arctic was covered with sea ice that year than was the case for the average from 1981 to 2000. Similarly, a value of 0.6 indicates a 40% reduction in sea ice extent compared to the 1981 to 2000 average. Note that by the end of the 21st century, the modeled summer sea ice extent in the Arctic is less than 20 percent of the 1981 to 2000 average.

Animations of the type indicated by the picture above are available in one size.

The animation is 720 x 720 resolution - twice the size of the images shown directly above.

We provide both an mpg-4 format animation (well-suited for Windows Media Player viewing) and and a .mov format animation that is well-suited for viewing with QuickTime player. (Clicking the picture above will direct you to the .mov format version.)

720 x 720 resolution, mpg-4 format, 240 frames total, 40 seconds at 6 fps [2.1MB]

720 x 720 resolution, .mov format, 240 frames total, 40 seconds at 6 fps [2.0MB]
animation caption:
This animation is identical to the one described above, except this one only shows the globe, and not the graph of the time varying Arctic sea ice extent. Please refer to the description above for more information.

# data[].attributes.attachment_link.title
The Shrinking Arctic Ice Cap ar4 - Geophysical Fluid Dynamics Laboratory

# data[].attributes.attachment_link.description
NOAA GFDL Climate Research Highlights Image Gallery The Shrinking Arctic Ice Cap Return to the main NOAA GFDL Climate Research Highlights web page CONTENTS 2-D Graphics & Maps Animations & Movies contacts: GFDL scientist contacts for this topic: Michael Winton, NOAA/GFDL Keith Dixon, NOAA/...

# data[].attributes.body
Clip from Cosmos

# data[].attributes.attachment_link.title
Weather Versus Climate Change | Cosmos: A Spacetime Odyssey

# data[].attributes.attachment_link.readable_text
The Keeling Curve is one of the most compelling pieces of scientific evidence that shows that carbon dioxide (CO ₂) is accumulating in our atmosphere. CO ₂ is a greenhouse gas. Greenhouse gases trap heat in the atmosphere and help keep the planet warm. More greenhouse gas molecules in the air means more heat is trapped, leading to an overall warming of the planet.

Click on the red circles above to learn more about the Keeling Curve, which plots CO2 in the Earth's atmosphere over time.

CO 2 is a molecule made up of one carbon atom and two oxygen atoms, and it moves in and out of the atmosphere through various process known as the carbon cycle. In the carbon cycle, natural processes like human respiration and volcanic activity release CO ₂. Plants absorb CO ₂ during photosynthesis and the ocean absorbs it when CO ₂ from the air mixes with seawater. However, human activities, such as the burning of fossil fuels, like coal, oil and natural gas, also release CO ₂ into the atmosphere.

Since the start of the Industrial Revolution in the late 1700s, humans have been emitting more and more CO ₂. At the same time, forests all over the world are being cleared for agriculture and development. Deforestation not only leaves fewer plants to absorb the increasing amounts of CO ₂, but also adds CO ₂ to the air when trees are burned or left to decay.

Until about the mid-20 th century many scientists thought that the oceans would easily absorb the excess CO ₂ emitted from fossil fuel burning, so there wasn't a great concern over the possible effects of increased emissions in the atmosphere. However, there wasn't a lot of data on the actual concentrations of CO ₂ in the atmosphere. In 1958, Charles Keeling of the Scripps Institute of Oceanography began measuring CO ₂ levels in the air at a weather station in Hawaii and at the South Pole. After a few years, Keeling observed a steady increase in atmospheric CO ₂, an indication that fossil-fuel emissions were building up in the atmosphere. Due to funding cuts, Keeling had to stop measurements at the South Pole, but the weather station in Hawaii continues to measure concentrations of CO ₂. The data from these measurements are plotted on a graph known as the Keeling Curve.

Keeling's findings were so profound that they prompted the National Oceanic and Atmospheric Administration (NOAA) to start monitoring CO ₂ concentrations in other locations around the world. And, in July 2014, NASA launched the Orbiting Carbon Observatory, a satellite designed to gather the most precise data ever for tracking the carbon cycle on Earth. All of this data indicates that CO ₂ is building up in Earth's atmosphere.

Discussion Questions

What does the Keeling Curve show about the concentrations of CO₂ in the Earth's atmosphere?

Why does the concentration of CO₂ go up and down throughout the year?

Why do you think Keeling chose Mauna Loa and Antarctica to measure atmospheric CO₂?

Why does the concentration of CO₂ increase over time?

What does an increase in CO₂ levels in the atmosphere mean for global warming?

This interactive explainer is part of our Clue into Climate collection of resources.
This interactive explainer is featured in our Clue into Climate e-book series. Click on the tabs below to download our free e-books or subscribe to our iTunes U course. You can also visit our e-books page to view our other offerings.
The Keeling Curve Explained

Author

QUEST Staff

QUEST, an Emmy Award-winning multimedia science series, has a new focus on the science of sustainability.The half-hour magazine style episodes are produced by a collaboration of six public broadcasters around the country and explore a wide variety of sustainability issues related to food, energy, water, climate and biodiversity. The story segments featured in each show are introduced by on-camera host, environmental journalist Simran Sethi. The series also includes half-hour specials that focus on a single topic.

All 2013-2014 television programs can be viewed online in their entirety or as individual segments by clicking on the titles and images listed below. The programs are also broadcast in each of our six PBS partner regions including North Carolina, Ohio, Nebraska, Northern California and the Pacific Northwest. Check local listings for broadcast dates and times.

# data[].attributes.attachment_link.keywords[]
national oceanic and atmospheric administration

# data[].attributes.attachment_link.description
The Keeling Curve is one of the most compelling pieces of scientific evidence that shows that carbon dioxide (CO 2) is accumulating in our atmosphere. CO 2 is a greenhouse gas. Greenhouse gases trap heat in the atmosphere and help keep the planet warm.

# data[].attributes.headline
Ocean Sink for Human-Made Carbon Dioxide Measured

# data[].attributes.subject
Ocean Sink for Human-Made Carbon Dioxide Measured

# data[].attributes.body
note original source at bottom of article

# data[].attributes.attachment_link.readable_text
Not all of the CO ₂ generated during the combustion of fossil fuels remains in the atmosphere and contributes to global warming. The ocean and the ecosystems on land take up considerable quantities of these human-made CO ₂ emissions from the atmosphere.

The ocean takes up CO ₂ in two steps: first, the CO ₂ dissolves in the surface water. Afterwards, the ocean's overturning circulation distributes it: ocean currents and mixing processes transport the dissolved CO ₂ from the surface deep into the ocean's interior, where it accumulates over time.
Carbon sink in the ocean
This overturning circulation is the driving force behind the oceanic sink for CO ₂. The size of this sink is very important for the atmospheric CO ₂ levels: without this sink, the concentration of CO ₂ in our atmosphere and the extent of anthropogenic climate change would be considerably higher.

Determining what share of the human-made CO ₂ the oceans absorb has long been a priority for climate researchers. An international team of scientists led by Nicolas Gruber, Professor for Environmental Physics at ETH Zurich, has now determined this oceanic sink over a period of 13 years. As reported in the latest issue of Science, the researchers have found that the ocean has taken up from the atmosphere as much as 34 gigatonnes (billions of metric tonnes) of human-made carbon between 1994 and 2007. This figure corresponds to 31 per cent of all anthropogenic CO ₂ emitted during that time.
The marine sink is intact
This percentage of CO ₂ taken up by the oceans has remained relatively stable compared to the preceding 200 years, but the absolute quantity has increased substantially. This is because as long as the atmospheric concentration of CO ₂ rises, the oceanic sink strengthens more or less proportionally: the more CO ₂ is in the atmosphere, the more is absorbed by the oceans -- until it becomes eventually saturated.

So far, that point has not been reached. "Over the examined period, the global ocean continued to take up anthropogenic CO ₂ at a rate that is congruent with the increase of atmospheric CO ₂ ," Gruber explains.

These data-based research findings also confirm various earlier, model-based estimates of the ocean sink for human-made CO ₂. "This is an important insight, giving us confidence that our approaches have been correct," Gruber adds. The results further allow the researchers to draw conclusions about the CO ₂ sink of the ecosystems on land, which are more difficult to determine.
Regional differences in the absorption rate
While the overall results suggest an intact ocean sink for human-made CO ₂, the researchers also discovered in the different ocean basins considerable deviations from the uptake expected from the rise in atmospheric CO ₂. The North Atlantic Ocean, for instance, absorbed 20 per cent less CO ₂ than expected between 1994 and 2007. "This is probably due to the slowdown of the North Atlantic Meridional Overturning Circulation in the late 1990s, which itself is most likely a consequence of climate variability," Gruber explains. But this lower sink in the North Atlantic was offset by a considerably greater uptake in the South Atlantic, such that the uptake by the entire Atlantic developed as expected.

The researchers documented similar fluctuations in the Southern Ocean, in the Pacific and in the Indian Ocean. Gruber emphasises: "We learned that the marine sink does not just respond to the increase in atmospheric CO ₂. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate."
Results of two surveys
The results are based on a global survey of CO ₂ and other chemical and physical properties in the various oceans, measured from the surface down to depths of up to 6 kilometres. Scientists from 7 countries participated in the internationally coordinated programme that started in 2003. Globally they carried out more than 50 research cruises up to 2013, which were then synthesized into a global data product.

For their analyses, the researchers used a new statistical method developed by Gruber and his former Ph.D. student, Dominic Clement. This method allowed them to distinguish between the changes in the man-made and the natural CO ₂ components that make up the changes in the total concentration of dissolved CO ₂ in the water. Natural CO ₂ refers to the amount of CO ₂ that existed in the oceans prior to industrialisation.

Gruber had already participated in a similar study around the turn of the millennium. Using observations obtained from the very first global CO ₂ survey conducted between the late 1980s and the mid-1990s, that study estimated that the ocean had taken up around 118 gigatonnes of carbon from the beginning of industrialisation around 1800 until 1994. His current team of researchers extended this analysis up to 2007, permitting them not only to establish the budget for man-made CO ₂ for the 1994 through 2007 period, but also to assess the intactness of the ocean carbon sink.
Increasing CO₂ content acidifies marine habitats
By moderating the rate of global warming, the oceanic sink for man-made CO ₂ provides an important service for humanity, but it has its price: the CO ₂ dissolved in the ocean acidifies the water. "Our data has shown that this acidification reaches deep into the ocean's interior, extending in part to depths of more than 3000 m," Gruber says.

This can have serious consequences for many marine organisms. Calcium carbonate spontaneously dissolves in acidified environments, which poses a hazard to mussels and corals whose shells and skeletons are made of calcium carbonate. The changing chemical composition of the ocean can also impact physiological processes such as the breathing of fish. Gruber is convinced: "Documenting the chemical changes imparted on the ocean as a result of human activity is crucial, not least to understand the impact of these changes on marine life."

# data[].attributes.attachment_link.keywords[]
oceanography; geography; global warming; environmental awareness; climate; ecosystems; forest; ecology

# data[].attributes.attachment_link.title
Ocean sink for human-made carbon dioxide measured

# data[].attributes.attachment_link.description
Not all of the CO 2 generated during the combustion of fossil fuels remains in the atmosphere and contributes to global warming. The ocean and the ecosystems on land take up considerable quantities of these human-made CO 2 emissions from the atmosphere.

# data[].attributes.headline
Monitor Local Air Quality Daily Across the US

# data[].attributes.subject
Monitor Local Air Quality Daily Across the US

# data[].attributes.body
Have students track various cities across the US looking for evidence that the Central Valley in California has the worst air quality in America!

# data[].attributes.attachment_link.readable_text
https://www.airnow.gov/announcement/3241

Save the Date: 2024 National Air Quality Conference

EPA will host the National Air Quality Conference (NAQC) March 18-21, 2024 at EPA's Research Triangle Park, North Carolina, campus.

Visit the NAQC webpage to learn more about this event and how to register

# data[].attributes.attachment_link.description
AirNow is your one-stop source for air quality data. Our recently redesigned site highlights air quality in your local area first, while still providing air quality information at state, national, and world views.

# data[].attributes.body
Find your local district and have students monitor hourly changes in air quality, looking for relationships such as temperature and ground level ozone.

# data[].attributes.attachment_link.readable_text
Learn about the latest progress in Valley Air Quality Read More

District's Tune In Tune Up program serves as model for the state according to UCLA report
A recent report by UCLA's Luskin School of Public Affairs Luskin Center for Innovation finds that the District's Tune In Tune Up Vehicle Repair Program not only has reduced vehicle emissions in the most environmentally disadvantaged region of the state but also has done so in an efficient manner that accomplishes equity in opportunity and benefit distribution. Read the Full report here. In response to the COVID-19 pandemic, the District modified the Tune In Tune Up Vehicle Repair Program to operate in the absence of weekend events. A Luskin Center report detailing the program changes and the community response can be found here.

Governing Board adopts 2021 Legislative Platform outlining District's priorities for the coming year View platform

EPA finds the Valley in Attainment of the 1-hour Ozone Standard
In July 2015, the District submitted an updated formal request to the California Air Resources Board (ARB) and U.S. Environmental Protection Agency (EPA) for a determination that the Valley has attained the federal 1-hour ozone standard, based on air quality data from the 2012-2014 period. In May of 2016, the EPA recognized this historic accomplishment by proposing to find the Valley in attainment of the 1-hour ozone standard and reaffirming the effectiveness of the investment and commitment by Valley businesses and residents to reduce emissions and improve public health. View EPA Proposal and Fact Sheet.

Valley Air District is Seeking Hearing Board Members in the Northern and Southern Region
The San Joaquin Valley Air Pollution Control District has three Hearing Boards which hold monthly hearings and make decisions on: variance applications pertaining to air quality rules and regulations affecting business and industry in the Valley; appeals to permits; orders of abatement, and revocations of permits. Notice Application

eTRIP Commute Verification Survey and Annual Report Deadlines
Worksites subject to the eTRIP rule (Rule 9410) are required to conduct a Commute Verification Survey no later than December 31 each year. This survey is designed to collect information as to how employees get to and from work each day during a week-long period. These worksites are also required to submit an Annual Report, consisting of the compiled results of the Commute Verification Survey, to the District by no later than March 31 of each following year.
For assistance with the Commute Verification Survey or the Annual Report, please visit www.valleyair.org/tripreduction.htm or contact the eTRIP Rule Small Business Assistance office at etrip@valleyair.org or call (559) 230-5950.

EPA redesignates the San Joaquin Valley to Attainment for the federal PM10 standard and approves the PM10 Maintenance Plan
The US Environmental Protection Agency redesignated the San Joaquin Valley to attainment of the PM10 National Ambient Air Quality Standard (NAAQS) and approved the 2007 PM10 Maintenance Plan. This historic achievement represents years of hard work by individuals, industry, Valley communities and the Air District.
Read the EPA's news release
Read the EPA's Final Approval of the SJV's PM10 Maintenance Plan and Request for Redesignation

Governing Board Meeting
The next scheduled meeting is beginning at 9:00 a.m. To view support materials for this meeting please click here.
Read the latest news about air quality issues.

# data[].attributes.attachment_link.description
Learn about the latest progress in Valley Air Quality Read More District's Tune In Tune Up program serves as model for the state according to UCLA report A recent report by UCLA's Luskin School of Public Affairs Luskin Center for Innovation finds that the District's Tune In Tune Up Vehicle Repair Program not only has reduced vehicle emissions in the most environmentally disadvantaged region of the state but also has done so in an efficient manner that accomplishes equity in opportunity and benefit distribution.

# data[].attributes.headline
The Cost of Human Impact on the Local Environment!

# data[].attributes.subject
The Cost of Human Impact on the Local Environment!

# data[].attributes.body
Anchor Phenomenon!

# data[].attributes.attachment_link.title
Life in San Joaquin valley, the place with the worst air pollution in America

# data[].attributes.attachment_link.description
Air quality in sun-baked California area has been identified as the worst in the US. Residents are concerned, but low wages mean long hours in the thick of it

# data[].attributes.headline
Human Impact on the Environment Causes Impact on Human Health!

# data[].attributes.subject
Human Impact on the Environment Causes Impact on Human Health!

# data[].attributes.attachment_link.readable_text
Air pollution causes a "huge" reduction in intelligence, according to new research, indicating that the damage to society of toxic air is far deeper than the well-known impacts on physical health.

The research was conducted in China but is relevant across the world, with 95% of the global population breathing unsafe air. It found that high pollution levels led to significant drops in test scores in language and arithmetic, with the average impact equivalent to having lost a year of the person's education.

"Polluted air can cause everyone to reduce their level of education by one year, which is huge," said Xi Chen at Yale School of Public Health in the US, a member of the research team. "But we know the effect is worse for the elderly, especially those over 64, and for men, and for those with low education. If we calculate [the loss] for those, it may be a few years of education."

Previous research has found that air pollution harms cognitive performance in students, but this is the first to examine people of all ages and the difference between men and women.

The damage in intelligence was worst for those over 64 years old, with serious consequences, said Chen: "We usually make the most critical financial decisions in old age." Rebecca Daniels, from the UK public health charity Medact, said: "This report's findings are extremely worrying."

Air pollution causes seven million premature deaths a year but the harm to people's mental abilities is less well known. A recent study found toxic air was linked to "extremely high mortality" in people with mental disorders and earlier work linked it to increased mental illness in children, while another analysis found those living near busy roads had an increased risk of dementia.

The new work, published in the journal Proceedings of the National Academy of Sciences, analysed language and arithmetic tests conducted as part of the China Family Panel Studies on 20,000 people across the nation between 2010 and 2014. The scientists compared the test results with records of nitrogen dioxide and sulphur dioxide pollution.

They found the longer people were exposed to dirty air, the bigger the damage to intelligence, with language ability more harmed than mathematical ability and men more harmed than women. The researchers said this may result from differences in how male and female brains work.

Derrick Ho, at the Hong Kong Polytechnic University, said the impact of air pollution on cognition was important and his group had similar preliminary findings in their work. "It is because high air pollution can potentially be associated with oxidative stress, neuroinflammation, and neurodegeneration of humans," he said.

Chen said air pollution was most likely to be the cause of the loss of intelligence, rather than simply being a correlation. The study followed the same individuals as air pollution varied from one year to the next, meaning that many other possible causal factors such as genetic differences are automatically accounted for.

The scientists also accounted for the gradual decline in cognition seen as people age and ruled out people being more impatient or uncooperative during tests when pollution was high.

Air pollution was seen to have a short-term impact on intelligence as well and Chen said this could have important consequences, for example for students who have to take crucial entrance exams on polluted days.

"But there is no shortcut to solve this issue," he said. "Governments really need to take concrete measures to reduce air pollution. That may benefit human capital, which is one of the most important driving forces of economic growth." In China, air pollution is declining but remains three times above World Health Organisation (WHO) limits.

According to the WHO, 20 of the world's most polluted cities are in developing countries. China, home to several of those cities, has been engaged in a " war against pollution " for the past five years.

The results would apply around the world, Chen added. The damage to intelligence was likely to be incremental, he said, with a 1mg rise in pollution over three years equivalent to losing more than a month of education. Small pollution particles are known to be especially damaging. "That is the same wherever you live. As human beings we have more in common than is different."

Aarash Saleh, a registrar in respiratory medicine in the UK and part of the Doctors Against Diesel campaign, said: "This study adds to the concerning bank of evidence showing that exposure to air pollution can worsen our cognitive function. Road traffic is the biggest contributor to air pollution in residential areas and the government needs to act urgently to remove heavily-polluting vehicles from our roads."

Daniels said: "The UK's air is illegally polluted and is harming people's health every day. Current policies are not up to the scale of the challenge: government must commit to bringing air pollution below legal limits as soon as possible."
Topics

# data[].attributes.attachment_link.title
Air pollution causes 'huge' reduction in intelligence, study reveals

# data[].attributes.attachment_link.description
Air pollution causes a "huge" reduction in intelligence, according to new research, indicating that the damage to society of toxic air is far deeper than the well-known impacts on physical health. The research was conducted in China but is relevant across the world, with 95% of the global population breathing unsafe air.