# data[].attributes.headline
GoPro: Climate Change and the Optimistic Future

# data[].attributes.subject
GoPro: Climate Change and the Optimistic Future

# data[].attributes.body
Kaylee Ahleman

# data[].attributes.attachment_link.title
GoPro: Climate Change and the Optimistic Future

# data[].attributes.attachment_link.description
Professor Richard Muller, of Berkeley Earth Foundation, discusses his views on climate change and how he hopes we can leave a better planet for our children.

# data[].attributes.headline
How Sea Level Rise is Related to Climate Change

# data[].attributes.subject
How Sea Level Rise is Related to Climate Change

# data[].attributes.body
https://oceanservice.noaa.gov/facts/sealevelclimate.html

# data[].attributes.body
Jaden Benschoter

# data[].attributes.attachment_link.description
Read National Geographic's latest stories about climate change.

# data[].attributes.headline
Do 97% of Climate Scientists Really Agree?

# data[].attributes.subject
Do 97% of Climate Scientists Really Agree?

# data[].attributes.body
Maddy Hawkins

# data[].attributes.attachment_link.title
Do 97% of Climate Scientists Really Agree?

# data[].attributes.body
1. What is the Paris Climate Agreement and why is it important?
2. Is climate change something to be concerned about?
3. Is climate change impacting our world? How do you know?

# data[].attributes.body
https://www.populationeducation.org/content/what-paris-agreement-and-why-it-important

# data[].attributes.body
Thomas B.

# data[].attributes.attachment_link.title
Electric Cars Aren't As Green As You Think | Adam Ruins Everything

# data[].attributes.body
Thomas Belleau

# data[].attributes.attachment_link.title
Adam Ruins Everything - Why the World Needs the Paris Agreement | truTV

# data[].attributes.attachment_link.description
When it comes to the shaping the future of our planet, the entire world needs to come together. Adam Conover's joined by Dr. Dale Jamieson, Professor of Environmental Studies and Philosophy at New York University, to explain how individual action can encourage collective responsibility.

# data[].attributes.headline
10 Reasons to Worry About Climate Change 

# data[].attributes.subject
10 Reasons to Worry About Climate Change 

# data[].attributes.body
Chris Warren
https://www.usnews.com/news/slideshows/top-10-reasons-to-worry-about-climate-change?slide=11

# data[].attributes.body
Tory C

# data[].attributes.attachment_link.readable_text
As speculation swirled over the White House's position on the landmark Paris climate agreement this week, a trio of determined governors had a few messages for the president.

"There's nothing Donald Trump can do in our states to stop us from advancing our policies," said Washington Gov. Jay Inslee.

"We are on track to meet the Paris accord," said California Gov. Jerry Brown. "This is America speaking."

To the chorus, New York Gov. Andrew Cuomo added, "You don't get great going backward."

Accompanied by former Secretary of State John Kerry, who steered the U.S. negotiations on Paris, the governors unveiled a new report on Wednesday from the U.S. Climate Alliance, the group they formed after President Trump announced he would withdraw from the historic climate agreement. (Only two other countries haven't signed the agreement, and Nicaragua media reported this week that their country's president plans to do so. If that happens, it would leave Syria and the United States alone in rejecting it if Trump pulls out.)

The U.S. Climate Alliance now represents 14 states and Puerto Rico, with the latest inclusion of North Carolina. Collectively, they are equivalent to the world's third-largest economy and account for more than 36 percent of the U.S. population. Each member has agreed to meet the U.S. commitments under the Paris climate deal.

The report's main finding: These states are on track to hit a 24 to 29 percent cut in greenhouse gas emissions below 2005 levels by 2025, roughly in line with the U.S. Paris pledge that Trump has disavowed. From 2005 to 2015, the states in the alliance had already cut their greenhouse gas emissions by 15 percent, the report said, while their economic output grew 14 percent.

"We have exploded the myth that you can't defeat climate change and grow your economy at the same time," Inslee said. "It's not a coincidence that our economies are doing well. It's a consequence of what we're doing to develop clean energy technology."

Cities and companies say, "We are still in."

The alliance is among a swell of coalitions and initiatives that have attempted to circumvent the Trump administration's threatened pullout from Paris and rollbacks on climate-related regulations, including the Obama administration's Clean Power Plan.

Among them are the "We Are Still In" coalition, which includes 2,300 cities, states, corporations, and universities that have pledged to uphold the Paris accord, and a parallel effort, organized by Brown and former New York Mayor Michael Bloomberg, called " America's Pledge," that's attempting to calculate the effects of climate action by its members and submit that tally at the United Nations' annual climate conference in Germany this fall.

Individual states, meanwhile, have advanced their own efforts. In July, California lawmakers approved an extension of the state's cap-and-trade program. In August, a coalition of nine Northeastern and mid-Atlantic states-the Regional Greenhouse Gas Initiative- agreed to cut an additional 30 percent of climate-warming pollution from the region's power plants between 2020 and 2030. (When asked by a reporter Wednesday whether California might consider linking its cap-and-trade program to New York's, Cuomo said, "The devil is in the details." Brown said, "I would very much welcome the state of New York into our cap and trade system.")

Gloomy projections but reason for hope.

The optimism contradicts some recent gloomy projections. Just last week, the U.S. Energy Information Agency issued its latest forecast, which said that global emissions of carbon dioxide would grow 16 percent by 2040 from 2015 levels.

Still, researchers say, there's reason for hope.

On Tuesday, the Natural Resources Defense Council issued a new report that said the U.S. can cut its greenhouse gas emissions 80 percent by 2050 if it moves quickly and aggressively toward renewable energy sources and investments in energy efficiency.

NRDC commissioned the analysis from consulting firm Energy + Environmental Economics to analyze how the United States can hit the 80 percent target-the amount the Intergovernmental Panel on Climate Change has said developed countries need to cut in order to keep global temperatures within 2 degrees of preindustrial levels.

"This is not a pipe dream," NRDC president Rhea Suh told reporters Tuesday. "It's a vision that builds on progress we're already making. With or without help from Washington, we'll keep moving forward."

"The key," Suh said, "is to cut our fossil fuel use at least 70 percent by investing in energy efficiency, shifting to electric cars and trains, getting more clean power from the wind and sun, and modernizing our electricity grid."

The NRDC projections rely heavily on energy efficiency and aggressive movement toward renewable energy sources-the same drivers that the governors say are sparking economic growth in their states.

"A lot of this depends on states and cities leading the way," said Amanda Levin, a climate and energy analyst for NRDC.

Want to encourage your city or state representatives to take more action? Take the first step by writing to your mayor asking that he or she sign on to the Ready for 100 pledge, signaling a commitment to switching over to 100 percent renewable energy. Here's some draft language you can use.

# data[].attributes.attachment_link.title
The Paris Climate Agreement Is Still Alive & Well In The US. Here's Why

# data[].attributes.attachment_link.description
As speculation swirled over the White House's position on the landmark Paris climate agreement this week, a trio of determined governors had a few messages for the president. "There's nothing Donald Trump can do in our states to stop us from advancing our policies," said Washington Gov. Jay Inslee.

# data[].attributes.body
https://climate.nasa.gov/system/content_pages/main_images/203_co2-graph-021116.jpeg

Abby Eller

# data[].attributes.headline
Six Pieces of Evidence For Climate Change

# data[].attributes.subject
Six Pieces of Evidence For Climate Change

# data[].attributes.body
Chris W.
https://www.popsci.com/evidence-climate-change-is-real

# data[].attributes.body
Maya Hillegonds

# data[].attributes.attachment_link.description
To learn about climate change, you first must know what climate is.

# data[].attributes.body
Tori P

# data[].attributes.attachment_link.title
Adam Ruins Everything - Climate Change is Already Happening. Now what?

# data[].attributes.attachment_link.description
The question isn't will warming happen; the question is how bad will it be? Subscribe: http://full.sc/1s9KQGe Watch Full Episodes for FREE: http://bit.ly/1Rw2yzp Check Adam's Sources: http://bit.ly/1Q7MHpK In Adam Ruins Everything, host Adam Conover employs a combination of comedy, history and science to dispel widespread misconceptions about everything we take for granted.

# data[].attributes.headline
short answers to hard questions about climate change

# data[].attributes.subject
short answers to hard questions about climate change

# data[].attributes.body
Arianna Scott

# data[].attributes.attachment_link.title
The Science of Climate Change Explained: Facts, Evidence and Proof

# data[].attributes.attachment_link.description
Definitive answers to the big questions.

# data[].attributes.body
J.J.

# data[].attributes.attachment_link.readable_text
Updated June 21, 2017 10:58:59

You have no doubt been hearing a lot about the Paris agreement and know that it pertains to climate change, but are too embarrassed at this stage to ask for an simple explanation of what it's all about.

That's where we come in. Here's an simple explanation of what it's all about.

First, you need to know what came before the Paris agreement.

UN Framework Convention on Climate Change

The Convention entered into force on March 21, 1994, and now has near-universal membership. It has been ratified by 197 countries. It represented the first time there had been universal recognition that there were a global warming problem.

It called for:

"The stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human) interference with the climate system".

The Kyoto Protocol

Though adopted on December 11, 1997, the Kyoto Protocol only entered into force on February 16, 2005, due to a complex ratification process.

It essentially operationalised the Convention. While the Convention only encouraged industrialised countries to stabilise greenhouse gas emissions, the Kyoto Protocol forced them to commit to doing so.

Paris Agreement: A reaction to the growing threat of global warming

At the Paris Climate Conference, in November/December of 2015, the need to accelerate anti-global-warming efforts was acknowledged.

The aim was to strengthen the worldwide response by:

Bringing all nations into a common cause, combating climate change and adapting to its effects

Enhancing support for developing countries in order to carry that out (The goal is to provide $100 billion a year)

Keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels

More ambitiously to pursue efforts to limit that rise to 1.5 degrees Celsius

The Paris Agreement came into force on November 4, 2016.

The agreement caps and reduces the use of hydrofluorocarbons (HFCs), described as the world's fastest-growing climate pollutant, in a gradual process beginning by 2019, with action by developed countries including the United States, the world's second-worst polluter.

More than 100 developing countries, including China, the world's top carbon emitter, will start taking action by 2024, when HFC consumption levels should peak.

Pull your weight, the world will be watching

The Paris Agreement focussed on nationally determined contributions (NDCs), which basically amounts to each country doing the best it can, depending on its specific circumstances. Each country has its own set of targets.

This means each country has to show that it is pulling its weight by reporting back regularly on its emissions and implementation efforts.

The Agreement states:

"Developed [countries] should continue taking the lead by undertaking economy-wide absolute emission reduction targets. Developing [countries] should continue enhancing their mitigation efforts, and are encouraged to move over time towards economy-wide emission reduction or limitation targets in the light of different national circumstances."

The idea is that a one-size-fits-all approach wouldn't be fair when wealthy industrialised countries are in a better position to move towards renewables without jeopardising their economies (plus they've been polluting for longer).

This is to reinforced by a global stocktake every five years to assess whether everyone is on track. The first of these stocktakes will take place in 2023.

Australia's target

On ratifying the Paris Agreement on November 9, 2016, Australia indicated it would reduce emissions to 26-28 per cent on 2005 levels by 2030.

This target represents a 50-52 per cent reduction in emissions per capita and a 64-65 per cent reduction in the emissions intensity of the economy between 2005 and 2030.

And this is where Australia looks like it may come a cropper, with a leaked report indicating the country is not on track to meet its commitments.

Topics: climate-change, environment, environmental-impact

First posted December 09, 2016 16:13:08

# data[].attributes.attachment_link.description
Updated June 21, 2017 10:58:59 You have no doubt been hearing a lot about the Paris agreement and know that it pertains to climate change, but are too embarrassed at this stage to ask for an simple explanation of what it's all about. That's where we come in.

# data[].attributes.body
COP 21: Why does Paris climate change conference matter? - BBC ...

# data[].attributes.headline
Why smart people deny climate change Keedyn Riedel

# data[].attributes.subject
Why smart people deny climate change Keedyn Riedel

# data[].attributes.body
http://bigthink.com/Mind-Matters/why-smart-people-deny-climate-change

# data[].attributes.body
https://climate.nasa.gov/evidence/

# data[].attributes.body
Brandon Rau

# data[].attributes.headline
what scientist know about climate change and hurricanes

# data[].attributes.subject
what scientist know about climate change and hurricanes

# data[].attributes.body
charlotte civis

# data[].attributes.attachment_link.readable_text
These days, as soon as winds hit 74 miles per hour or barometric pressure drops below 990 millibars, people want to know: Is climate change behind this hurricane? It's an even more pressing question when a giant storm like Harvey is followed by an even more gigantic one like Irma, which itself is being followed by Jose and Katia. Climate scientists continue to wrestle with the connection between global warming and individual storms, but they're more confident than ever that there's some linkage.

1. Is climate change to blame for Harvey and Irma?

Climate scientists are increasingly comfortable connecting global warming to the unprecedentedly high ocean temperatures that fuel some storms. Scientists in Germany and the U.K. drew a direct link between global warming and the intensity of Irma and the destructiveness of Harvey. Climate change can't be blamed for the existence of these two juggernauts -- there have always been hurricanes, after all -- but it does shape the remarkable conditions they're occurring in. The fuel for tropical storms is ocean heat, and each storm's top winds have a theoretical speed limit, determined by how much of that fuel is in their tank.

2. How hot is the ocean?

Hotter than at any previous moment in recorded history, thanks to human-driven climate change. The global average sea-surface temperature for July was 1.24 degrees Fahrenheit above the 20th century average, making it the third-hottest July for oceans, behind 2016 and 2015. The waters where Irma was born were about 2 degrees Fahrenheit above normal or 1 degree Celsius.

3. What does the extra heat do?

In addition to raising water temperatures, it heats up the air, which makes storms wetter. Every uptick in temperature increases the air's water-holding capacity exponentially. As a result, there's now at least 4 percent more water vapor in the air than a century ago.

4. What does all that mean?

So far, the scientific consensus is that global warming will make more-intense storms more frequent, even if the total number of storms stays the same or drops.

5. How did scientists reach that consensus?

Climate scientists rely on powerful computer models that simulate the behavior of the atmosphere, oceans and land. Through testing, they make sure these model-Earths can reproduce weather events that have already occurred. Then the models can be used to project into the future. There is not as much historical data as scientists would like to support a more confident statement about hurricane frequency going forward.

6. What explains the recent run of quiet hurricane seasons?

The U.S. did indeed go without a strike by a major hurricane (Category 3 or above) between 2005 and 2017, the longest gap on record going back to 1851. But the Atlantic Ocean spun up some monster storms during that time. Last year, Hurricane Matthew killed more than 500 people across the Caribbean. In 2015, Hurricane Joaquin grew with explosive power, trapping the freighter El Faro and sinking it with the loss of all hands. In addition, 2010, 2011 and 2012 all posted 19 named storms, making them tied for most active year, along with 1995 and 1887. And Superstorm Sandy, which hit the U.S. in 2012, started as a hurricane near Jamaica. The U.S. also suffered billions in damages from smaller storms such as Ike in 2008 and Irene in 2011, which caused severe flooding as far north as Vermont.

7. What else are scientists trying to figure out?

How the extra heat is changing overall atmospheric dynamics, and what the impact of those changes might be. Hurricane Harvey, for example, is one of several recent weather disasters marked by a shocking staying power, punishing whole regions for days or weeks on end -- or longer. Researchers are trying to understand climate change's connection to episodes in which the jet-stream -- the high-flying river of air that meanders around the higher-to-mid latitudes -- gets locked into one place for an extended period. They suspect that may have played a role in a massive heatwave in Russia and flooding in Pakistan in 2010, the Texas drought of 2011 and the multiyear California drought that began around the same time.

8. What do scientists disagree about?

For one thing, how powerful an influence the Arctic, which is warming twice as quickly as the rest of the planet, has on weather extremes in the sub-tropics. There's also a debate over whether the Atlantic has a long-term cycle of warming and cooling that's separate from warming induced by industrialization.

9. Are Irma and Harvey likely to change the climate debate?

The U.S. quickly went from world leader in global climate diplomacy to an outlier when President Donald Trump walked away from the 2015 Paris accords, which continue to be supported by virtually all other nations. There is interesting research into behavior and decision-making on climate and other issues. Extreme weather and palpable changes in long-term trends can be influential in helping people understand what's going on - even if political affiliations restrict what they are comfortable saying out loud. On the other hand, the record hurricane year of 2005, when there were 28 named storms, including Katrina, was followed by deepening political polarization on the issue, in the U.S. if not elsewhere.

The Reference Shelf

A QuickTake explainer on hurricanes and typhoons.

A study of Superstorm Sandy predicts more extreme weather ahead.

The U.S. National Oceanic and Atmospheric Administration's overview of research on global warming and hurricanes.

A Nature article on "gray swan" hurricanes.

World Weather Attribution is a research partnership between universities and research groups that evaluates extreme weather events for human influence.

# data[].attributes.attachment_link.keywords[]
national oceanic and atmospheric administration

# data[].attributes.attachment_link.title
What Scientists Know About Climate Change and Hurricanes: QuickTake Q&A

# data[].attributes.attachment_link.description
These days, as soon as winds hit 74 miles per hour or barometric pressure drops below 990 millibars, people want to know: Is climate change behind this hurricane? It's an even more pressing question when a giant storm like Harvey is followed by an even more gigantic one like Irma, which itself is being followed by Jose and Katia.

# data[].attributes.body
Katie evans

# data[].attributes.attachment_link.readable_text
If we want to fight climate change should we have fewer children - or should we be focusing more on reducing consumption? Is the answer different depending on where you live in the world? And in any case, how might we make people and politicians engage with this issue?

Those are just some of the questions Guardian supporters asked deputy membership editor Vicky Frost to put to our panel in this edition of We Need to Talk About. She is joined by Damian Carrington, the Guardian's environment editor; Lucy Lamble, the Guardian's executive editor for global development; John Vidal, the multi-award winning former Guardian environment editor; and Afua Hirsch, a writer and broadcaster for the Guardian and Sky News among others, who has also worked in international development and the law.

We also hear from Kimberly Nicholas, a senior lecturer at Lund University, Sweden, who was part of a team whose research has attempted to quantify the environmental impact of having a child. ( You can read the Guardian's report on this work here.)

You'll hear a wide variety of responses and viewpoints as supporters and journalists tussle with these at times tricky and divisive questions - considering why campaigning organisations might have tended not to engage with the issue historically, and whether the decision to live a childfree life is properly understood and respected by society.

And if you enjoy this, and want to catch up with the rest of the series, you can listen to discussions on Brexit and nationalism, among other subjects, here. Guardian supporters can also suggest future topics for discussion by emailing us at weneedtotalkabout@theguardian.com - we welcome your input.

# data[].attributes.attachment_link.title
We need to talk about ... Population and climate change

# data[].attributes.attachment_link.description
In this monthly podcast, Guardian supporters ask the questions and a Guardian panel try to provide the answers. This episode focuses on whether people should be having fewer children for the sake of the planet - and if so, how that societal change might happen

# data[].attributes.body
Matthew Riedberger
https://climate.nasa.gov/

# data[].attributes.body
http://bigthink.com/Mind-Matters/why-smart-people-deny-climate-change

# data[].attributes.headline
Cold region ‘tipping point’ now inevitable in northern Europe

# data[].attributes.subject
Cold region ‘tipping point’ now inevitable in northern Europe

# data[].attributes.body
jason barksdale

# data[].attributes.attachment_link.readable_text
The decline of northern Europe's cold regions is now inevitable due to climate change. This is the conclusion of our recent research published in Nature Communications, and represents a 'tipping point' for these unique environments.

Even with optimistic estimates of future carbon emissions, our results suggest that areas covered by so-called periglacial zones will reduce dramatically by 2050, and will "almost disappear" by 2100.

Today, these periglacial zones make up about a quarter of the Earth's land surface and are mostly found in the far north and south, and at high altitudes.

These regions are important for Scandinavian's identity, representing globally vital ecosystems, and highly variable, iconic and largely undisturbed landscapes.

Losing them would have major impacts on landscapes and biodiversity, and could trigger so-called climate "feedbacks" - processes that once initiated, e.g. CO ₂ release from thawing permafrost soils, can further amplify the negative effects of climate change.
Read More: More extreme warm days in a warmer climate
Frost-related ground processes characterise cold regions

Together with our colleague from the University of Exeter, UK, we studied four processes that characterise periglacial zones:

1. snow accumulation sites

2. palsa mires - peat formations with permanent ice core

3. "frost churning" - which refers to mixing of materials caused by freezing and thawing of uppermost soil layers

4. slow mass wasting of surficial soil material moved downslope by freeze-thaw processes.

Using field surveys, aerial imaginary, and computer models we mapped the local variation of a periglacial zone in northern Europe at an unprecedented level of detail. This is important, as previous studies have not been able to realistically identify the distribution and climatic sensitivity of periglacial zones.

Although the studied area covers just a portion of the wider periglacial zone, it is well representative of similar climatically sensitive environments across cold-regions.

Our results show that today, half of the northern European study area has suitable conditions to support periglacial activity, reinforcing their importance in characterizing the geomorphology of cold-climate regions.
Read More: Arctic soils: a ticking climate time bomb
Northern landscapes affected by climate change

But importantly, our study shows that many of the frost-driven processes acting today are already at the margin of the climate in which they can exist, and small changes in climate conditions could trigger large reductions in the extent of the periglacial zone.

We investigated how the extent of these periglacial zones might change in the future, according to three possible scenarios of carbon emissions.

Even based on the optimistic scenario, where immediate emission cuts are required, we predict a 72 per cent reduction in the current periglacial zone in this area of northern Europe by 2050.

By 2100, periglacial zones will only exist in high mountain regions. This could lead to changes in landscape dynamics in the future as the climate warms, meaning that ground ice may no longer be the significant geomorphological agent that shapes the Earth's surface in these regions.
Read More: One quarter of the Arctic is a hotbed for overlooked greenhouse gas
Big implications for cold-regions

Our results showing a potential for drastic landscape changes have many important implications for the people, animal, and plants occupying cold-regions.

First, these anticipated changes in periglacial zones can feedback to the regional climate system via alterations in the carbon cycle and ground surface reflectance--the light reflected at the surface of the Earth. This means that as highly reflective snow and ice retreats and is replaced by less reflective shrub vegetation, less of the sun's radiation is reflected from the surface of the Earth and more is absorbed by the darker soil and plants, leading to additional local warming.

Meanwhile, permanently frozen peat soils in these areas are major stores of organic carbon, and the thawing of these releases greenhouse gases (CO ₂, CH ₄, and N ₂ O) with potentially global implications for the climate system.

Furthermore, the results indicate significant changes in northern European plant life. Many rare species can only be sustained in areas of intense frost activity or late-lying snow packs, so the disappearance of such unique environments will reduce biodiversity.
Read More: Four big changes in the Arctic and what to do about them
More work to be done

The precise nature of the changes in such high-latitude landscapes may be complex and is difficult for us to forecast today.

Therefore, new data and sophisticated computer models are required to increase our understanding of how climate and land surface processes interact. This will help us to identify critical tipping points in cold-regions' nature and help inform decision makers.

---------------
The research is part of the INFRAHAZARD project, funded by the Academy of Finland. The study was also funded by the EU's Seventh Framework Programme for Research and Technological Development and by the EU HELIX programme.

# data[].attributes.attachment_link.title
Cold region 'tipping point' now inevitable in northern Europe

# data[].attributes.attachment_link.description
The decline of northern Europe's cold regions is now inevitable due to climate change. This is the conclusion of our recent research published in Nature Communications, and represents a 'tipping point' for these unique environments. Even with optimistic estimates of future carbon emissions, our results suggest that areas covered by so-called periglacial zones will reduce dramatically by 2050, and will "almost disappear" by 2100.

# data[].attributes.headline
Cold region ‘tipping point’ now inevitable in northern Europe

# data[].attributes.subject
Cold region ‘tipping point’ now inevitable in northern Europe

# data[].attributes.body
Augustus Neil

# data[].attributes.attachment_link.readable_text
The decline of northern Europe's cold regions is now inevitable due to climate change. This is the conclusion of our recent research published in Nature Communications, and represents a 'tipping point' for these unique environments.

Even with optimistic estimates of future carbon emissions, our results suggest that areas covered by so-called periglacial zones will reduce dramatically by 2050, and will "almost disappear" by 2100.

Today, these periglacial zones make up about a quarter of the Earth's land surface and are mostly found in the far north and south, and at high altitudes.

These regions are important for Scandinavian's identity, representing globally vital ecosystems, and highly variable, iconic and largely undisturbed landscapes.

Losing them would have major impacts on landscapes and biodiversity, and could trigger so-called climate "feedbacks" - processes that once initiated, e.g. CO ₂ release from thawing permafrost soils, can further amplify the negative effects of climate change.
Read More: More extreme warm days in a warmer climate
Frost-related ground processes characterise cold regions

Together with our colleague from the University of Exeter, UK, we studied four processes that characterise periglacial zones:

1. snow accumulation sites

2. palsa mires - peat formations with permanent ice core

3. "frost churning" - which refers to mixing of materials caused by freezing and thawing of uppermost soil layers

4. slow mass wasting of surficial soil material moved downslope by freeze-thaw processes.

Using field surveys, aerial imaginary, and computer models we mapped the local variation of a periglacial zone in northern Europe at an unprecedented level of detail. This is important, as previous studies have not been able to realistically identify the distribution and climatic sensitivity of periglacial zones.

Although the studied area covers just a portion of the wider periglacial zone, it is well representative of similar climatically sensitive environments across cold-regions.

Our results show that today, half of the northern European study area has suitable conditions to support periglacial activity, reinforcing their importance in characterizing the geomorphology of cold-climate regions.
Read More: Arctic soils: a ticking climate time bomb
Northern landscapes affected by climate change

But importantly, our study shows that many of the frost-driven processes acting today are already at the margin of the climate in which they can exist, and small changes in climate conditions could trigger large reductions in the extent of the periglacial zone.

We investigated how the extent of these periglacial zones might change in the future, according to three possible scenarios of carbon emissions.

Even based on the optimistic scenario, where immediate emission cuts are required, we predict a 72 per cent reduction in the current periglacial zone in this area of northern Europe by 2050.

By 2100, periglacial zones will only exist in high mountain regions. This could lead to changes in landscape dynamics in the future as the climate warms, meaning that ground ice may no longer be the significant geomorphological agent that shapes the Earth's surface in these regions.
Read More: One quarter of the Arctic is a hotbed for overlooked greenhouse gas
Big implications for cold-regions

Our results showing a potential for drastic landscape changes have many important implications for the people, animal, and plants occupying cold-regions.

First, these anticipated changes in periglacial zones can feedback to the regional climate system via alterations in the carbon cycle and ground surface reflectance--the light reflected at the surface of the Earth. This means that as highly reflective snow and ice retreats and is replaced by less reflective shrub vegetation, less of the sun's radiation is reflected from the surface of the Earth and more is absorbed by the darker soil and plants, leading to additional local warming.

Meanwhile, permanently frozen peat soils in these areas are major stores of organic carbon, and the thawing of these releases greenhouse gases (CO ₂, CH ₄, and N ₂ O) with potentially global implications for the climate system.

Furthermore, the results indicate significant changes in northern European plant life. Many rare species can only be sustained in areas of intense frost activity or late-lying snow packs, so the disappearance of such unique environments will reduce biodiversity.
Read More: Four big changes in the Arctic and what to do about them
More work to be done

The precise nature of the changes in such high-latitude landscapes may be complex and is difficult for us to forecast today.

Therefore, new data and sophisticated computer models are required to increase our understanding of how climate and land surface processes interact. This will help us to identify critical tipping points in cold-regions' nature and help inform decision makers.

---------------
The research is part of the INFRAHAZARD project, funded by the Academy of Finland. The study was also funded by the EU's Seventh Framework Programme for Research and Technological Development and by the EU HELIX programme.

# data[].attributes.attachment_link.title
Cold region 'tipping point' now inevitable in northern Europe

# data[].attributes.attachment_link.description
The decline of northern Europe's cold regions is now inevitable due to climate change. This is the conclusion of our recent research published in Nature Communications, and represents a 'tipping point' for these unique environments. Even with optimistic estimates of future carbon emissions, our results suggest that areas covered by so-called periglacial zones will reduce dramatically by 2050, and will "almost disappear" by 2100.

# data[].attributes.body
Beth Robertson

# data[].attributes.body
Cameron Brehmer

# data[].attributes.attachment_link.readable_text
Back to blog

What can teenagers do to fight climate change?

An email came in recently from H.H., a thirteen-year-old on a "year long quest to find out how I can make a difference" in the fight against climate change. The email included a list of questions. They're good questions, so I'll answer them here as best as I can. And since I have no particular expertise in the advice-for-youngsters field, please add your own thoughts in comments.
1. Is it possible to stop climate change?
Not entirely, but it should be possible to stop the worst effects of climate change.

The climate reacts slowly to all the carbon dioxide we've been adding to the atmosphere. It will take decades or even hundreds of years for the full effects of the fossil fuel we've already burned to be felt. So it isn't really possible to fully stop climate change.

But most scientists think it is possible to avoid the worst effects of climate change. We have a short time in which to act. If we can hold emissions down - and then gradually eliminate them - we should be able to prevent the really bad scenarios that scientists are warning us about.
2. Do we need to have a global government to address climate change or does local governments work too?
We don't need a global government, but we do need a global agreement between governments. There is only one climate, so the nations of the earth need to cooperate to reach the common goal of reducing carbon emissions. The good news is that we've cooperated before. For example, over twenty years ago, 186 nations agreed to a treaty to address the hole in the ozone layer. Climate change is a much bigger problem, but at least we know what needs to be done.
3. How did you first come to know or get interested in climate change?
Scientists have been studying climate change since before I was born, but like most people, I didn't pay much attention until the issue started becoming more urgent in the 1990s. Once I started to learn about climate change, I realized that it's a much bigger problem than most, because it affects every aspect of the environment and the economy.

TerraPass began as a school project in 2004. Since then, of course, I've learned more than ever about the causes of climate change and - more importantly - the potential solutions.
4. How has knowing about climate change influenced your life?
I spend every day working on climate change, so it's influenced my life quite a bit! And, like a lot of people, I take steps to conserve energy usage. Beyond those obvious things, here are some other ways climate change has influenced my life:

Good (yes, there are some good things): I enjoy working in an area that I feel is important to the future health and wealth of the planet. I'm a science geek, and science of climate and energy turns out to be completely fascinating. I'm also a politics geek, and the politics of climate change are also fascinating - and totally frustrating. These days, I'm feeling optimistic that we're starting to move in the right direction. So that's nice.

Bad: I wish climate change would go away! I would prefer to live in a world where we had access to cheap, clean energy. But we don't, so I worry in particular about some of the potentially irreversible effects of climate change, such as biodiversity loss.
5. What do you think is the best way to convince people that climate change is happening?
Good question. I'm pretty sure the answer lies in helping people understand that climate change isn't only a threat, but also an opportunity. In 50 years, we will all be healthier and wealthier than we are now - and the environment will be safe. But only if we start acting now.

Of course, some people will never be convinced, so we should focus most of our energy on motivating the people who do understand the problem (the majority of Americans) to push for solutions.
6. Can you suggest other sources - media, places to visit, activities to take part in, or people I could contact to help me understand and fight against climate change?
There's so much information available online that I hardly know where to begin. You might want to check out this list of the top 50 green blogs, and find the ones that interest you most.

There's also an interesting study guide related to the movie An Inconvenient Truth. One of the best ways for you to get involved is through your school.

Of course, you can also get involved by finding ways to reduce your carbon footprint. You don't drive yet, so you're already doing a good job on that front. Perhaps you can find ways to green your home.

Update: Via this Grist post, I found this area of the Clinton Global Initiative web site that lists out ideas for "commitments" that young people can take to fight climate change. Lots of ideas in there.
7. Why do you think people don't believe that climate change is happening?
This is a complicated topic. I think there are a few reasons. The first is that the science of climate change is difficult. The second is that climate change is scary. A third reason - and this may be the most important one - is that the politics of climate change are a mess. I know that's a vague answer, but you could write a whole book about this.
8. What do you think I should do after I finish college to help save earth?
This question is easy: don't worry about it. Here's why:

You won't graduate from college for eight years. In eight years, the world will be very different. We'll have a different government. We'll have new technologies. We'll have new laws and new international agreements. No one can predict what the world will look like in eight years, so just study hard and see what opportunities arise.

More importantly, what you should do depends entirely on what you like to do. All sorts of people are needed to help fight climate change: scientists, engineers, legislators, educators, entrepreneurs, businesspeople, financiers, activists, and the list goes on. The best thing for you to do is whatever you most enjoy, because that's where you'll make the greatest difference. And the only way to find that out is to try out a bunch of different things, talk to people who do work you find interesting, and learn as much as possible.

It's really difficult to convey the sheer breadth and diversity of opportunities available to someone interested in the environment. (See here if you want a taste.) Fortunately for you, this is one question you can put off answering for a few years.

Found photo available under Creative Commons license from Flickr user foundphotoslj.

# data[].attributes.attachment_link.title
What can teenagers do to fight climate change? - terrapass

# data[].attributes.attachment_link.description
Back to blog An email came in recently from H.H., a thirteen-year-old on a "year long quest to find out how I can make a difference" in the fight against climate change. The email included a list of questions. They're good questions, so I'll answer them here as best as I can.

# data[].attributes.headline
The US Defense Department takes climate change seriously

# data[].attributes.subject
The US Defense Department takes climate change seriously

# data[].attributes.body
Emily Dennis

# data[].attributes.attachment_link.readable_text
While President Donald Trump has dismissed climate change as a hoax, the Department of Defense is focused on understanding and preparing for continued climate disruption and the security threats it poses in a warming world.

The US experienced three large-scale disasters in succession - hurricanes Harvey, Irma and Maria - which has strained our resources, our politics and the infrastructure that helps bring aid to battered areas. Even in an era of highly polarized politics, however, the US remains a fairly stable government system. When these disasters hit other places that aren't so stable, they can create regional and even international security problems.

"One of the components of climate change that makes it a threat or a risk to national security is [that] it can make already tenuous, or frankly bad, places much worse and, occasionally, catastrophically so," says retired Rear Adm. David Titley. Titley led the US Navy's task force on climate change and is now a professor of meteorology at Pennsylvania State University.

"So much depends on local governance, on the inherent strength and resilience of the communities affected," Titley says. "This is why you see people like Defense Secretary Mattis talk so strongly about the need for not only the military to be funded, but for adequate funding for US Agency for International Development, or USAID; for our State Department to be adequately funded and adequately manned, because the military can come in initially and try to help stabilize the situation, but the US military is not going to be the one that rebuilds these societies."

The short- and long-term stability of vulnerable countries hit by disaster depends a great deal on other US federal agencies, like the State Department, Titley says. Expertise from many other components of the federal government help stabilize local governments, because "that's really a great way to buy down, if you will, the risk of climate change - to have governments who care about their people, who take care of their people and have the tools and means to do so."

Titley notes that James Mattis was "pretty clear on this early on in his tenure as Secretary of Defense." His answers to written questions from congressional leaders indicated he understands that the climate is changing and that "those changes, if unmanaged, compose a risk to US security operations and US Department of Defense."

"He's not going to put climate risk and climate change up on a pedestal and make it the one and only thing we worry about, but he's also not saying, 'This doesn't exist or it's a hoax,' or all of the other things that we've heard from other parts of this administration," Titley says.

Titley has a saying he uses to describe how things work at Defense: "If the boss is interested, everybody else is fascinated." Mattis's acceptance of climate change as a security risk allows others in the department, including the Joint Chiefs of Staff, to begin to plan for its effects, he says.

"For a lot of the readiness of the Department of Defense, it doesn't even really matter why [the climate] is changing," he adds. The department's internal message, he says, is "'we know it's changing; we know it's changing pretty quickly, and we'd better be ready for that, because if we just plan for the past we're going to be surprised,'- and that's not where the Department of Defense wants to be."
This article is based on an interview that aired on PRI's Living on Earth with Steve Curwood.

# data[].attributes.attachment_link.title
The US Defense Department takes climate change seriously

# data[].attributes.attachment_link.description
While President Donald Trump has dismissed climate change as a hoax, the Department of Defense is focused on understanding and preparing for continued climate disruption and the security threats it poses in a warming world.

# data[].attributes.headline
How Do We Know That Climate Change Is Not A Natural Cycle?

# data[].attributes.subject
How Do We Know That Climate Change Is Not A Natural Cycle?

# data[].attributes.attachment_link.readable_text
Answer

If the Earth's temperature had been steady for millions of years and only started rising in the past half century or so, the answer would be obvious.

But the temperature has not been steady at all. Twenty thousand years ago, the planet was going through an ice age, with glaciers covering much of Europe and North America. A hundred million years ago, the Earth was so warm that crocodile-like creatures prowled through tropical vegetation not far from the North Pole.

In other words, climate variations are not at all unusual. So how do we know this one is caused by humans?

Several reasons. First, we know that burning coal, oil, and gas releases heat-trapping carbon dioxide, or CO2. And we know, thanks to careful measurements that started in the late 1950s, that CO2 levels in the atmosphere have been steadily climbing as we burn more. Not only that - chemists can tell the difference between the CO2 released naturally by plants and animals and the CO2 from burning fossil fuels. About a quarter of the CO2 now in the atmosphere is the result of human activity.

The one obvious natural suspect - the Sun - can pretty much be ruled out. It is an obvious suspect because astronomers know that the Sun can vary in brightness. When it does, the amount of heat it sends to the Earth varies too. It would not take much brightening to cause the increases in temperature we have seen. But satellites have been monitoring the Sun since the 1970s - when the fastest warming has been taking place - and the brightening just is not there.

There is plenty of other evidence - the pattern of warming, for example, which is greatest in the Arctic, and the pace, which is faster (as best we can tell) than prehistoric warming episodes. The upper atmosphere has actually cooled, because so much heat has been trapped below.

The bottom line is that nobody has come up with a natural explanation for the current warming episode that fits the observations. At the same time, the un-natural explanation-that our industrial civilization is a big part of the cause-fits the evidence.

That's how we know it is not natural. One last thing. If the Earth has survived earlier warming episodes, what is so bad about this one even if it is not natural? The problem is that our civilization - where cities are located, where we grow food, where we get fresh water-is all based on the climate we have experienced for the last 10,000 years. So are many of the world's ecosystems. If the climate changes, many of those things will suddenly find themselves in the wrong place.

How do we know?

Two NASA satellites, known as ACE and STEREO, measure the brightness of the Sun from Earth orbit, where the dimming effects of our atmosphere are minimal. Another satellite, called Aqua, looks down with an instrument called AIRS at the atmosphere from above to measure how much carbon dioxide is in it. And, as we discussed in the answer to the first question, we are measuring the Earth's radiation budget from space.

# data[].attributes.attachment_link.title
How do we know global warming is not a natural cycle?

# data[].attributes.attachment_link.description
Answer If the Earth's temperature had been steady for millions of years and only started rising in the past half century or so, the answer would be obvious. But the temperature has not been steady at all. Twenty thousand years ago, the planet was going through an ice age, with glaciers covering much of Europe and North America.

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

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

# 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.body
Lauryn Craig

# data[].attributes.attachment_link.description
To learn about climate change, you first must know what climate is.

# data[].attributes.body
Amaris Benschoter

# data[].attributes.attachment_link.readable_text
Climate change, also known as global warming, has received much attention. It is also a source of much controversy. Yet while debate continues about how to best understand and manage our changing climate, scientists agree that it does have an impact. In fact, one of the essential principles of teaching climate change to students is the message that it has consequences for the earth and human lives.

According to the National Oceanic and Atmospheric Administration (NOAA), students should understand:

The effects of human-caused climate change can already be seen, for example in the melting polar ice caps. More consequences are expected, including the extinction of certain species and loss of forests.

Some of the infrastructure created by humans is in danger, such as the extra burden placed on the energy grid from high temperatures.

How the climate and precipitation patterns change can threaten agriculture and food security.

Teaching about climate change can be a challenge. For one, being too alarming can lead people to ignore or deny warnings. Also, the impact of climate change may not be relatable for many students. It helps to bring the lesson close to home as much as possible. For middle students, NOAA suggests talking about the effects of climate on animal habitats. Middle schoolers can also understand that there are solutions they can be a part of at home and school. Suggestions for high school students include using geography to study sea level or biology to study how species adapt. High schoolers can also use case studies to understand more complex climate solutions.

Students can learn that climate change is no longer just of interest to scientists. Insurance companies, emergency responders, the military and more are concerned about climate change. Students themselves can take an active role by learning about it today, and perhaps choosing a field in which they tackle climate change in the future.
Sources: National Oceanic and Atmospheric Administration; Climate Literacy and Energy Awareness Network
Resources for Educators:

Introduction to Earth's Dynamically Changing Climate, NASA and PBS TeacherLine
This activity engages students in examining evidence of global warming throughout the globe.
ACTIVITY, ALL AGES

Climate Kids: NASA's Eyes on the Earth, NASA
The climate change section of this website offers content, links to games and a visually appealing discussion guide for teachers to present the evidence for climate change throughout the planet. WEBSITE, LINKS TO RESOURCES, ALL AGES

Climate Change, Global Systems Science
This online textbook provides a detailed overview of climate change, with chapters covering government action on climate change, the history and controversy surrounding climate change, and the role greenhouse gases play.
HIGH SCHOOL, TEXTBOOK

A Brief Mathematical Guide to Earth Science and Climate Change, National Aeronautics and Space Administration
This resource offers a large collection of activities for grades 4-12. Teachers will find background information, problem and answer keys, discussion of alignment with standards, and a detailed table of contents for easy identification of activities.
ACTIVITIES, GRADES 4-12

Climate Change in my Backyard, Chicago Botanic Garden
This guide incorporates the NASA climate change curriculum to provide activities over four units.
ACTIVITIES, GRADES 7-9

Climate Change in my Backyard, Chicago Botanic Garden
This guide incorporates the NASA climate change curriculum to provide activities over four units.
ACTIVITIES, GRADES 10-12

Global Climate Change: Understanding the Greenhouse Effect (Lesson 1), PBS Learning MediaThis lesson involves studying climate change, the role of greenhouse gases and the impact human behavior has on global warming.
ACTIVITY, LESSON PLAN GRADES 9-12+

Global Climate Change: The Effects of Global Warming (Lesson 2), PBS Learning MediaIntended to follow the lesson, Global Climate Change: Understanding the Greenhouse Effect, students will conduct an experiment to learn about carbon dioxide levels found in four different gases. They will think about carbon dioxide on a global scale, looking at evidence of global warming. This lesson also involves thinking through how human behavior contributes to global warming.
ACTIVITY, LESSON PLAN, GRADES 9-12+

Evidence of Global Warming, KQED Education Network
This interactive web page provides an overview of global warming with clickable topics to learn about the evidence that it is taking place. There are also questions for students to consider included.
INTERACTIVE WEB CONTENT, GRADES 9-12
Talking to Children about Climate Change, National Oceanic and Atmospheric Administration
This web content provides an overview of climate change topics, and addresses strategies for explaining this complex issue to students. Links to additional information are included.
TEACHER GUIDE, ALL AGES

# data[].attributes.attachment_link.title
Climate Change Education: Essential Information for Educators

# data[].attributes.attachment_link.description
Climate change , also known as global warming , has received much attention. It is also a source of much controversy. Yet while debate continues about how to best understand and manage our changing climate, scientists agree that it does have an impact.

# data[].attributes.body
Hailey Hilton
https://climate.nasa.gov/resources/education/pbs_modules/lesson1Overview/

# data[].attributes.headline
Bill Nye Emoji Climate Change                          

# data[].attributes.subject
Bill Nye Emoji Climate Change                          

# data[].attributes.body
Emily Dennis

# data[].attributes.attachment_link.title
Bill Nye Explains Climate Change with Emoji

# data[].attributes.headline
The Physical Science behind Climate Change

# data[].attributes.subject
The Physical Science behind Climate Change

# data[].attributes.attachment_link.readable_text
Editor's note: This story was originally posted in the July 2007 issue, and has been reposted to highlight the long history of Nobelists publishing in Scientific American.

For a scientist studying climate change, "eureka" moments are unusually rare. Instead progress is generally made by a painstaking piecing together of evidence from every new temperature measurement, satellite sounding or climate-model experiment. Data get checked and rechecked, ideas tested over and over again. Do the observations fit the predicted changes? Could there be some alternative explanation? Good climate scientists, like all good scientists, want to ensure that the highest standards of proof apply to everything they discover.

And the evidence of change has mounted as climate records have grown longer, as our understanding of the climate system has improved and as climate models have become ever more reliable. Over the past 20 years, evidence that humans are affecting the climate has accumulated inexorably, and with it has come ever greater certainty across the scientific community in the reality of recent climate change and the potential for much greater change in the future. This increased certainty is starkly reflected in the latest report of the Intergovernmental Panel on Climate Change (IPCC), the fourth in a series of assessments of the state of knowledge on the topic, written and reviewed by hundreds of scientists worldwide.

The panel released a condensed version of the first part of the report, on the physical science basis of climate change, in February. Called the "Summary for Policymakers," it delivered to policymakers and ordinary people alike an unambiguous message: scientists are more confident than ever that humans have interfered with the climate and that further human-induced climate change is on the way. Although the report finds that some of these further changes are now inevitable, its analysis also confirms that the future, particularly in the longer term, remains largely in our hands-the magnitude of expected change depends on what humans choose to do about greenhouse gas emissions.

The physical science assessment focuses on four topics: drivers of climate change, changes observed in the climate system, understanding cause-and-effect relationships, and projection of future changes. Important advances in research into all these areas have occurred since the IPCC assessment in 2001. In the pages that follow, we lay out the key findings that document the extent of change and that point to the unavoidable conclusion that human activity is driving it.

Drivers of Climate Change
Atmospheric concentrations of many gases-primarily carbon dioxide, methane, nitrous oxide and halocarbons (gases once used widely as refrigerants and spray propellants)-have increased because of human activities. Such gases trap thermal energy (heat) within the atmosphere by means of the well-known greenhouse effect, leading to global warming. The atmospheric concentrations of carbon dioxide, methane and nitrous oxide remained roughly stable for nearly 10,000 years, before the abrupt and rapidly accelerating increases of the past 200 years. Growth rates for concentrations of carbon dioxide have been faster in the past 10 years than over any 10-year period since continuous atmospheric monitoring began in the 1950s, with concentrations now roughly 35 percent above preindustrial levels (which can be determined from air bubbles trapped in ice cores). Methane levels are roughly two and a half times preindustrial levels, and nitrous oxide levels are around 20 percent higher.

How can we be sure that humans are responsible for these increases? Some greenhouse gases (most of the halocarbons, for example) have no natural source. For other gases, two important observations demonstrate human influence. First, the geographic differences in concentrations reveal that sources occur predominantly over land in the more heavily populated Northern Hemisphere. Second, analysis of isotopes, which can distinguish among sources of emissions, demonstrates that the majority of the increase in carbon dioxide comes from combustion of fossil fuels (coal, oil and natural gas). Methane and nitrous oxide increases derive from agricultural practices and the burning of fossil fuels.

Climate scientists use a concept called radiative forcing to quantify the effect of these increased concentrations on climate. Radiative forcing is the change that is caused in the global energy balance of the earth relative to preindustrial times. (Forcing is usually expressed as watts per square meter.) A positive forcing induces warming; a negative forcing induces cooling. We can determine the radiative forcing associated with the long-lived greenhouse gases fairly precisely, because we know their atmospheric concentrations, their spatial distribution and the physics of their interaction with radiation.

Climate change is not driven just by increased greenhouse gas concentrations; other mechanisms- both natural and human-induced-also play a part. Natural drivers include changes in solar activity and large volcanic eruptions. The report identifies several additional significant human-induced forcing mechanisms-microscopic particles called aerosols, stratospheric and tropospheric ozone, surface albedo (reflectivity) and aircraft contrails-although the influences of these mechanisms are much less certain than those of greenhouse gases.

Investigators are least certain of the climatic influence of something called the aerosol cloud albedo effect, in which aerosols from human origins interact with clouds in complex ways and make the clouds brighter, reflecting sunlight back to space. Another source of uncertainty comes from the direct effect of aerosols from human origins: How much do they reflect and absorb sunlight directly as particles? Overall these aerosol effects promote cooling that could offset the warming effect of long-lived greenhouse gases to some extent. But by how much? Could it overwhelm the warming? Among the advances achieved since the 2001 IPCC report is that scientists have quantified the uncertainties associated with each individual forcing mechanism through a combination of many modeling and observational studies. Consequently, we can now confidently estimate the total human- induced component. Our best estimate is some 10 times larger than the best estimate of the natural radiative forcing caused by changes in solar activity.

This increased certainty of a net positive radiative forcing fits well with the observational evidence of warming discussed next. These forcings can be visualized as a tug-of-war, with positive forcings pulling the earth to a warmer climate and negative ones pulling it to a cooler state. The result is a no contest; we know the strength of the competitors better than ever before. The earth is being pulled to a warmer climate and will be pulled increasingly in this direction as the "anchorman" of greenhouse warming continues to grow stronger and stronger.

Observed Climate Changes
The many new or improved observational data sets that became available in time for the 2007 IPCC report allowed a more comprehensive assessment of changes than was possible in earlier reports. Observational records indicate that 11 of the past 12 years are the warmest since reliable records began around 1850.

he odds of such warm years happening in sequence purely by chance are exceedingly small. Changes in three important quantities-global temperature, sea level and snow cover in the Northern Hemisphere-all show evidence of warming, although the details vary. The previous IPCC assessment reported a warming trend of 0.6 ± 0.2 degree Celsius over the period 1901 to 2000. Because of the strong recent warming, the updated trend over 1906 to 2005 is now 0.74 ± 0.18 degree C. Note that the 1956 to 2005 trend alone is 0.65 ± 0.15 degree C, emphasizing that the majority of 20th-century warming occurred in the past 50 years. The climate, of course, continues to vary around the increased averages, and extremes have changed consistently with these averages-frost days and cold days and nights have become less common, while heat waves and warm days and nights have become more common.

The properties of the climate system include not just familiar concepts of averages of temperature, precipitation, and so on but also the state of the ocean and the cryosphere (sea ice, the great ice sheets in Greenland and Antarctica, glaciers, snow, frozen ground, and ice on lakes and rivers). Complex interactions among different parts of the climate system are a fundamental part of climate change-for example, reduction in sea ice increases the absorption of heat by the ocean and the heat flow between the ocean and the atmosphere, which can also affect cloudiness and precipitation.

A large number of additional observations are broadly consistent with the observed warming and reflect a flow of heat from the atmosphere into other components of the climate system. Spring snow cover, which decreases in concert with rising spring temperatures in northern midlatitudes, dropped abruptly around 1988 and has remained low since. This drop is of concern because snow cover is important to soil moisture and water resources in many regions.

In the ocean, we clearly see warming trends, which decrease with depth, as expected. These changes indicate that the ocean has absorbed more than 80 percent of the heat added to the climate system: this heating is a major contributor to sea-level rise. Sea level rises because water expands as it is warmed and because water from melting glaciers and ice sheets is added to the oceans. Since 1993 satellite observations have permitted more precise calculations of global sea-level rise, now estimated to be 3.1 ± 0.7 millimeters per year over the period 1993 to 2003. Some previous decades displayed similarly fast rates, and longer satellite records will be needed to determine unambiguously whether sea-level rise is accelerating. Substantial reductions in the extent of Arctic sea ice since 1978 (2.7 ± 0.6 percent per decade in the annual average, 7.4 ± 2.4 percent per decade for summer), increases in permafrost temperatures and reductions in glacial extent globally and in Greenland and Antarctic ice sheets have also been observed in recent decades. Unfortunately, many of these quantities were not well monitored until recent decades, so the starting points of their records vary.

Hydrological changes are broadly consistent with warming as well. Water vapor is the strongest greenhouse gas; unlike other greenhouse gases, it is controlled principally by temperature. It has generally increased since at least the 1980s. Precipitation is very variable locally but has increased in several large regions of the world, including eastern North and South America, northern Europe, and northern and central Asia. Drying has been observed in the Sahel, the Mediterranean, southern Africa and parts of southern Asia. Ocean salinity can act as a massive rain gauge. Near-surface waters of the oceans have generally freshened in middle and high latitudes, while they have become saltier in lower latitudes, consistent with changes in large-scale patterns of precipitation.

Reconstructions of past climate-paleoclimate- from tree rings and other proxies provide important additional insights into the workings of the climate system with and without human influence. They indicate that the warmth of the past half a century is unusual in at least the previous 1,300 years. The warmest period between A.D. 700 and 1950 was probably A.D. 950 to 1100, which was several tenths of a degree C cooler than the average temperature since 1980.

Attribution of Observed Changes
Although confidence is high both that human activities have caused a positive radiative forcing and that the climate has actually changed, can we confidently link the two? This is the question of attribution: Are human activities primarily responsible for observed climate changes, or is it possible they result from some other cause, such as some natural forcing or simply spontaneous variability within the climate system? The 2001 IPCC report concluded it was likely (more than 66 percent probable) that most of the warming since the mid-20th century was attributable to humans. The 2007 report goes significantly further, upping this to very likely (more than 90 percent probable).

The source of the extra confidence comes from a multitude of separate advances. For a start, observational records are now roughly five years longer, and the global temperature increase over this period has been largely consistent with IPCC projections of greenhouse gas-driven warming made in previous reports dating back to 1990. In addition, changes in more aspects of the climate have been considered, such as those in atmospheric circulation or in temperatures within the ocean. Such changes paint a consistent and now broadened picture of human inter-vention. Climate models, which are central to attribution studies, have also improved and are able to represent the current climate and that of the recent past with considerable fidelity. Finally, some important apparent inconsistencies noted in the observational record have been largely resolved since the last report.

The most important of these was an apparent mismatch between the instrumental surface temperature record (which showed significant warming over recent decades, consistent with a human impact) and the balloon and satellite atmospheric records (which showed little of the expected warming). Several new studies of the satellite and balloon data have now largely resolved this discrepancy-with consistent warming found at the surface and in the atmosphere.

An experiment with the real world that duplicated the climate of the 20th century with constant (rather than increasing) greenhouse gases would be the ideal way to test for the cause of climate change, but such an experiment is of course impossible. So scientists do the next best thing: they simulate the past with climate models.

Two important advances since the last IPCC assessment have increased confidence in the use of models for both attribution and projection of climate changes. The first is the development of a comprehensive, closely coordinated ensemble of simulations from 18 modeling groups around the world for the historical and future evolution of the earth's climate. Using many models helps to quantify the effects of uncertainties in various climate processes on the range of model simulations. Although some processes are well understood and well represented by physical equations (the flow of the atmosphere and ocean or the propagation of sunlight and heat, for example), some of the most critical components of the climate system are less well understood, such as clouds, ocean eddies and transpiration by vegetation. Modelers approximate these components using simplified representations called parameterizations. The principal reason to develop a multimodel ensemble for the IPCC assessments is to understand how this lack of certainty affects attribution and prediction of climate change. The ensemble for the latest assessment is unprecedented in the number of models and experiments performed.

The second advance is the incorporation of more realistic representations of climate processes in the models. These processes include the behavior of atmospheric aerosols, the dynamics (movement) of sea ice, and the exchange of water and energy between the land and the atmosphere. More models now include the major types of aerosols and the interactions between aerosols and clouds.

When scientists use climate models for attribution studies, they first run simulations with estimates of only "natural" climate influences over the past 100 years, such as changes in solar output and major volcanic eruptions. They then run models that include human-induced increases in greenhouse gases and aerosols. The results of such experiments are striking. Models using only natural forcings are unable to explain the observed global warming since the mid-20th century, whereas they can do so when they include anthropogenic factors in addition to natural ones. Large-scale patterns of tempera-ture change are also most consistent between models and observations when all forcings are included.

Two patterns provide a fingerprint of human influence. The first is greater warming over land than ocean and greater warming at the surface of the sea than in the deeper layers. This pattern is consistent with greenhouse gas-induced warming by the overlying atmosphere: the ocean warms more slowly because of its large thermal inertia. The warming also indicates that a large amount of heat is being taken up by the ocean, demonstrating that the planet's energy budget has been pushed out of balance.

A second pattern of change is that while the troposphere (the lower region of the atmosphere) has warmed, the stratosphere, just above it, has cooled. If solar changes provided the dominant forcing, warming would be expected in both atmospheric layers. The observed contrast, however, is just that expected from the combination of greenhouse gas increases and stratospheric ozone decreases. This collective evidence, when subjected to careful statistical analyses, provides much of the basis for the increased confidence that human influences are behind the observed global warming. Suggestions that cosmic rays could affect clouds, and thereby climate, have been based on correlations using limited rec-ords; they have generally not stood up when tested with additional data, and their physical mechanisms remain speculative.

What about at smaller scales? As spatial and temporal scales decrease, attribution of climate change becomes more difficult. This problem arises because natural small-scale temperature variations are less "averaged out" and thus more readily mask the change signal. Nevertheless, continued warming means the signal is emerging on smaller scales. The report has found that human activity is likely to have influenced temperature significantly down to the continental scale for all continents except Antarctica.

Human influence is discernible also in some extreme events such as unusually hot and cold nights and the incidence of heat waves. This does not mean, of course, that individual extreme events (such as the 2003 European heat wave) can be said to be simply "caused" by human-induced climate change-usually such events are complex, with many causes. But it does mean that human activities have, more likely than not, affected the chances of such events occurring.

Projections of Future Changes
How will climate change over the 21st century? This critical question is addressed using simulations from climate models based on projections of future emissions of greenhouse gases and aerosols. The simulations suggest that, for greenhouse gas emissions at or above current rates, changes in climate will very likely be larger than the changes already observed during the 20th century. Even if emissions were immediately reduced enough to stabilize greenhouse gas concentrations at current levels, climate change would continue for centuries. This inertia in the climate results from a combination of factors. They include the heat capacity of the world's oceans and the millennial timescales needed for the circulation to mix heat and carbon dioxide throughout the deep ocean and thereby come into equilibrium with the new conditions.

To be more specific, the models project that over the next 20 years, for a range of plausible emissions, the global temperature will increase at an average rate of about 0.2 degree C per decade, close to the observed rate over the past 30 years. About half of this near-term warming represents a "commitment" to future climate change arising from the inertia of the climate system response to current atmospheric concentrations of greenhouse gases.

The long-term warming over the 21st century, however, is strongly influenced by the future rate of emissions, and the projections cover a wide variety of scenarios, ranging from very rapid to more modest economic growth and from more to less dependence on fossil fuels. The best estimates of the increase in global temperatures range from 1.8 to 4.0 degrees C for the various emission scenarios, with higher emissions leading to higher temperatures. As for regional impacts, projections indicate with more confidence than ever before that these will mirror the patterns of change observed over the past 50 years (greater warming over land than ocean, for example) but that the size of the changes will be larger than they have been so far.

The simulations also suggest that the removal of excess carbon dioxide from the atmosphere by natural processes on land and in the ocean will become less efficient as the planet warms. This change leads to a higher percentage of emitted carbon dioxide remaining in the atmosphere, which then further accelerates global warming. This is an important positive feedback on the carbon cycle (the exchange of carbon compounds throughout the climate system). Although models agree that carbon-cycle changes represent a positive feedback, the range of their responses remains very large, depending, among other things, on poorly understood changes in vegetation or soil uptake of carbon as the climate warms. Such processes are an important topic of ongoing research.

The models also predict that climate change will affect the physical and chemical characteristics of the ocean. The estimates of the rise in sea level during the 21st century range from about 30 to 40 centimeters, again depending on emissions. More than 60 percent of this rise is caused by the thermal expansion of the ocean. Yet these model-based estimates do not include the possible acceleration of recently observed increases in ice loss from the Greenland and Antarctic ice sheets. Although scientific understanding of such effects is very limited, they could add an additional 10 to 20 centimeters to sea-level rises, and the possibility of significantly larger rises cannot be excluded. The chemistry of the ocean is also affected, as the increased concentrations of atmospheric carbon dioxide will cause the ocean to become more acidic.

Some of the largest changes are predicted for polar regions. These include significant increases in high-latitude land temperatures and in the depth of thawing in permafrost regions and sharp reductions in the extent of summer sea ice in the Arctic basin. Lower latitudes will likely experience more heat waves, heavier precipitation, and stronger (but perhaps less frequent) hurricanes and typhoons. The extent to which hurricanes and typhoons may strengthen is uncertain and is a subject of much new research.

Some important uncertainties remain, of course. For example, the precise way in which clouds will respond as temperatures increase is a critical factor governing the overall size of the projected warming. The complexity of clouds, however, means that their response has been frustratingly difficult to pin down, and, again, much research remains to be done in this area.

We are now living in an era in which both humans and nature affect the future evolution of the earth and its inhabitants. Unfortunately, the crystal ball provided by our climate models becomes cloudier for predictions out beyond a century or so. Our limited knowledge of the response of both natural systems and human society to the growing impacts of climate change compounds our uncertainty. One result of global warming is certain, however. Plants, animals and humans will be living with the consequences of climate change for at least the next thousand years.

# data[].attributes.attachment_link.authors[].name
William Collins, Robert Colman, James Haywood, Martin R. Manning, Philip Mote

# data[].attributes.attachment_link.title
The Physical Science behind Climate Change

# data[].attributes.attachment_link.description
Editor's note: This story was originally posted in the July 2007 issue, and has been reposted to highlight the long history of Nobelists publishing in Scientific American. For a scientist studying climate change, "eureka" moments are unusually rare. Instead progress is generally made by a painstaking piecing together of evidence from every new temperature measurement, satellite sounding or climate-model experiment.

# data[].attributes.attachment_link.readable_text
Global Warming

Throughout its long history, Earth has warmed and cooled time and again. Climate has changed when the planet received more or less sunlight due to subtle shifts in its orbit, as the atmosphere or surface changed, or when the Sun's energy varied. But in the past century, another force has started to influence Earth's climate: humanity

How does this warming compare to previous changes in Earth's climate? How can we be certain that human-released greenhouse gases are causing the warming? How much more will the Earth warm? How will Earth respond? Answering these questions is perhaps the most significant scientific challenge of our time.

What is Global Warming?

Global warming is the unusually rapid increase in Earth's average surface temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels. The global average surface temperature rose 0.6 to 0.9 degrees Celsius (1.1 to 1.6° F) between 1906 and 2005, and the rate of temperature increase has nearly doubled in the last 50 years. Temperatures are certain to go up further.

Earth's natural greenhouse effect

Earth's temperature begins with the Sun. Roughly 30 percent of incoming sunlight is reflected back into space by bright surfaces like clouds and ice. Of the remaining 70 percent, most is absorbed by the land and ocean, and the rest is absorbed by the atmosphere. The absorbed solar energy heats our planet.

As the rocks, the air, and the seas warm, they radiate "heat" energy (thermal infrared radiation). From the surface, this energy travels into the atmosphere where much of it is absorbed by water vapor and long-lived greenhouse gases such as carbon dioxide and methane.

When they absorb the energy radiating from Earth's surface, microscopic water or greenhouse gas molecules turn into tiny heaters- like the bricks in a fireplace, they radiate heat even after the fire goes out. They radiate in all directions. The energy that radiates back toward Earth heats both the lower atmosphere and the surface, enhancing the heating they get from direct sunlight.

This absorption and radiation of heat by the atmosphere-the natural greenhouse effect-is beneficial for life on Earth. If there were no greenhouse effect, the Earth's average surface temperature would be a very chilly -18°C (0°F) instead of the comfortable 15°C (59°F) that it is today.

See Climate and Earth's Energy Budget to read more about how sunlight fuels Earth's climate.

The enhanced greenhouse effect

What has scientists concerned now is that over the past 250 years, humans have been artificially raising the concentration of greenhouse gases in the atmosphere at an ever-increasing rate, mostly by burning fossil fuels, but also from cutting down carbon-absorbing forests. Since the Industrial Revolution began in about 1750, carbon dioxide levels have increased nearly 38 percent as of 2009 and methane levels have increased 148 percent.

The atmosphere today contains more greenhouse gas molecules, so more of the infrared energy emitted by the surface ends up being absorbed by the atmosphere. Since some of the extra energy from a warmer atmosphere radiates back down to the surface, Earth's surface temperature rises. By increasing the concentration of greenhouse gases, we are making Earth's atmosphere a more efficient greenhouse.

# data[].attributes.attachment_link.description
Global warming is happening now, and scientists are confident that greenhouse gases are responsible. To understand what this means for humanity, it is necessary to understand what global warming is, how scientists know it's happening, and how they predict future climate.

# data[].attributes.body
Jacob Klonowski

# data[].attributes.body
Kyle Christy

# data[].attributes.attachment_link.keywords[]
the effect of nuclear war on climate change

# data[].attributes.attachment_link.title
The effect of Nuclear War on Climate Change | Weather Underground

# data[].attributes.attachment_link.description
Weather Underground provides local & long range Weather Forecast, weather reports, maps & tropical weather conditions for locations worldwide.

# data[].attributes.body
https://www.youtube.com/watch?v=AN5wNFlwiag
(Hey to those who recognize Adam)

# 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.body
https://newsela.com/read/govt-EPA-climate-midwest/id/28476

# data[].attributes.headline
Evidence of climate change given by NASA

# data[].attributes.subject
Evidence of climate change given by NASA

# data[].attributes.body
https://climate.nasa.gov/evidence/

# data[].attributes.body
B. Robertson

# data[].attributes.attachment_link.readable_text
Bertha Vazquez has taught earth science for more than 25 years.

"For many years I covered the basic standard, probably like most people in the country do," she says.

Then one day, she says, she decided to throw that all out the window after seeing former Vice President Al Gore speak at the University of Miami at a screening of An Inconvenient Truth, his documentary about climate change.

"And it really ... hit me. This is 2007 and, I've got to tell you, I lost sleep," Vazquez says.

A study in the journal Science this spring found that half of U.S. science teachers spend less than two hours on climate change each year.

And teachers in Florida may be no exception. Florida is one state that has not adopted somewhat newly designed science standards that are gaining popularity and teach about human-induced climate change.

So, Vazquez says, the next day in class she resolved to do more. The school where she teaches, George Washington Carver Middle School, sits just eight feet above sea level; several of the surrounding neighborhoods are even lower.

She thought, by the time her students were adults with families of their own, storm surges could bring waves lapping at their front doors. "If we just despair, it leads to inactivity," she says. "So I thought, 'If they're doing positive things, it will be helpful.' "

And positive things they're doing.

Vazquez's students meet climate scientists in class and calculate how many desalination plants it would take to turn rising seas into a sustainable source of fresh water (too many).

There's the work they've done on the school itself. On a walk around campus, Vazquez points out improvements her students instigated over the years or installed themselves: smart thermostats, energy-efficient light bulbs, and reflective white paint on the roof to keep the building cooler.

Finally, there are students like Penny Richards. She says after a year in Vazquez's class, she reads climate news while she rides the bus to school.

In class, Bertha Vazquez says she tries to balance the fear that comes with taking climate science seriously, and measured optimism. She draws on examples of past environmental successes - like how the ozone layer is on the mend - to show what collective action can accomplish.

"In your lifetime, you're going to see a sea change," Vazquez explains to her students at the end of class. "I don't want you all to walk out of here like, 'Woe is me, it's going to be over!' "

Privately, though, she acknowledges a cognitive dissonance in teaching about the onset of a planet-sized crisis while smiling at sixth-graders.

"You can't depress the hell out of them ... if you want them to start looking for solutions," she says. "So I don't really go there. Do I feel that way personally? Yes ... but in class I put on my happy face."

A pivotal moment in Vazquez's class often comes when her students open an app called Eyes on the Rise, where they plug in their address and learn how far they live above sea level.

"One kid will say, 'I'm 10 feet above sea level. I'm going to be OK,' " Vazquez explains. "I'll say 'Yeah, you'll be on a little hill, but what about everybody else around you? We're all in this boat together.' "

For students like seventh-grader Penny Richards - the one who reads climate news on the bus - that's a sobering moment. "Miami's basically at sea level. I live next to a canal," she reasons. "Life as we know it, we're going to have to move to an entirely different setting soon if we don't do something about this, because my entire neighborhood will be underwater."

The operative phrase there, of course, is "do something." Penny and her classmates think we can.

# data[].attributes.attachment_link.title
Teaching Middle-Schoolers Climate Change Without Terrifying Them

# data[].attributes.attachment_link.description
Bertha Vazquez has taught earth science for more than 25 years. "For many years I covered the basic standard, probably like most people in the country do," she says. Then one day, she says, she decided to throw that all out the window after seeing former Vice President Al Gore speak at the University of Miami at a screening of An Inconvenient Truth, his documentary about climate change.

# data[].attributes.body
Elizabeth Masterson
https://climate.nasa.gov/vital-signs/sea-level/

# data[].attributes.attachment_link.title
Newsela | Instructional Content Platform

# data[].attributes.attachment_link.description
Newsela is an Instructional Content Platform that supercharges reading engagement and learning in every subject.

# data[].attributes.headline
Scientific consensus: Earths climate is warming

# data[].attributes.subject
Scientific consensus: Earths climate is warming

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

# data[].attributes.attachment_link.readable_text
It's important to remember that scientists always focus on the evidence, not on opinions. Scientific evidence continues to show that human activities ( primarily the human burning of fossil fuels) have warmed Earth's surface and its ocean basins, which in turn have continued to impact Earth's climate. This is based on over a century of scientific evidence forming the structural backbone of today's civilization.

NASA Global Climate Change presents the state of scientific knowledge about climate change while highlighting the role NASA plays in better understanding our home planet. This effort includes citing multiple peer-reviewed studies from research groups across the world, illustrating the accuracy and consensus of research results (in this case, the scientific consensus on climate change) consistent with NASA's scientific research portfolio.

With that said, multiple studies published in peer-reviewed scientific journals show that climate-warming trends over the past century are extremely likely due to human activities. In addition, most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources.

AMERICAN SCIENTIFIC SOCIETIES

Statement on Climate Change from 18 Scientific Associations

"Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (2009) ²

SCIENCE ACADEMIES

International Academies: Joint Statement

"Climate change is real. There will always be uncertainty in understanding a system as complex as the world's climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies)

U.S. GOVERNMENT AGENCIES

INTERGOVERNMENTAL BODIES

Intergovernmental Panel on Climate Change

"It is unequivocal that the increase of CO ₂, methane, and nitrous oxide in the atmosphere over the industrial era is the result of human activities and that human influence is the principal driver of many changes observed across the atmosphere, ocean, cryosphere, and biosphere.

"Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact." ¹³⁻¹⁷

OTHER RESOURCES

List of Worldwide Scientific Organizations

The following page lists the nearly 200 worldwide scientific organizations that hold the position that climate change has been caused by human action.
http://www.opr.ca.gov/facts/list-of-scientific-organizations.html

U.S. Agencies

The following page contains information on what federal agencies are doing to adapt to climate change.
https://www.c2es.org/site/assets/uploads/2012/02/climate-change-adaptation-what-federal-agencies-are-doing.pdf
Technically, a "consensus" is a general agreement of opinion, but the scientific method steers us away from this to an objective framework. In science, facts or observations are explained by a hypothesis (a statement of a possible explanation for some natural phenomenon), which can then be tested and retested until it is refuted (or disproved). As scientists gather more observations, they will build off one explanation and add details to complete the picture. Eventually, a group of hypotheses might be integrated and generalized into a scientific theory, a scientifically acceptable general principle or body of principles offered to explain phenomena.
References​

# data[].attributes.attachment_link.title
Scientific Consensus: Earth's Climate is Warming

# data[].attributes.attachment_link.description
Vital Signs of the Planet: Global Climate Change and Global Warming. Partial list of leading scientific organizations endorsing human-induced climate change, along with a selection of related resources.

# data[].attributes.headline
7 Species hit hard by climate change- Including 1 that's already extinct. 

# data[].attributes.subject
7 Species hit hard by climate change- Including 1 that's already extinct. 

# data[].attributes.attachment_link.readable_text
Climate change is doing "widespread and consequential" harm to animals and plants, which are struggling to adapt to new conditions, according to a major report released Monday.

The report, from the UN's Intergovernmental Panel on Climate Change (IPCC), finds that many life-forms are moving north or into deeper waters to survive as their habitats shift.

They're also being forced to change their behaviors. For instance, many birds are nesting, breeding, and migrating earlier as spring arrives sooner than before. (Related: " Ten U.S. Species Feeling Global Warming's Heat.")

"Evidence of climate change impacts is strongest and most comprehensive for natural systems," the report said. (See: " New Climate Change Report Warns of Dire Consequences.")

Current research suggests that winners in this transformation will be adaptable species that are expanding their ranges, including many weeds and pests, and also cold-sensitive, invasive species like the Burmese python in Florida, said Peter Alpert, a program director in environmental biology at the U.S. National Science Foundation in Arlington, Virginia.

The losers, Alpert said, will likely be the species that are highly specialized in what they eat or where they live, especially those whose habitats disappear completely.

That might include species such as koalas, which depend mainly on eucalyptus for survival, and the many animal and plant species that live only on isolated mountaintops.

"You have to hope that they can change fast enough to keep up with it," he said. "Species have experienced swings like this in the past, but [the changes] have probably taken a thousand times longer."

Bob Scholes and Hans-Otto Pörtner, both IPCC authors who contributed to the report's ecosystems chapters, agreed, in a joint statement to National Geographic, that the current human-made climate change is happening much faster than in the past. (See a map of global warming's effects.)

Scholes, a systems ecologist at the Council for Scientific and Industrial Research (CSIR) in Pretoria, South Africa, and Pörtner, an animal physiologist and marine biologist based at the Alfred Wegener Institute in Bremerhaven, Germany, highlighted six species that are already in decline due to climate change:

Orange-spotted filefish (Oxymonacanthus longirostris). The filefish dwells in coral reef habitats, on which it is totally dependent, and which themselves are declining in part due to climate change. In addition, the orange-spotted filefish is highly sensitive to warm water: The animal went extinct in Japan during an episode of warmer ocean temperatures in 1988.

Quiver tree (Aloe dichotoma). This succulent tree is endemic to (and emblematic of) the arid west of South Africa and Namibia. Chapter Four of the fifth IPCC report "shows, for the first time, that the rate of climate change can be just as important for species survival as the magnitude, and that trees are the most vulnerable to rapid change," Scholes said. A well-studied species, the quiver tree is unable to grow and disperse quickly enough to keep up with a fast-changing climate. (Related: "Rain Forest Plants Race to Outrun Global Warming.")

Polar bear. The large predator's story is well known: The Arctic sea ice on which the animals hunt is progressively disappearing during the summer. Sea ice is forming later in the fall and disappearing earlier in the spring. "As the Arctic sea ice retreats, polar bears have to exploit alternative food sources, such as on land," the scientists said, and some hungry polar bears have turned to goose eggs. But it's not the best alternative, Steven Amstrup, chief scientist for Polar Bears International, noted in a previous story. "Some media reports have suggested that this might mean polar bears could just come ashore and eat terrestrial foods and somehow do fine without the sea ice," Amstrup said. "We have absolutely no evidence that they have the ability to do this." (Read "On Thin Ice" in National Geographic magazine.)

Adélie penguin. These Antarctic birds mostly live on tiny crustaceans called krill. Krill live on the undersides of ice sheets, where they find refuge and algae as food. But as Antarctic sea ice retreats, krill populations are falling-meaning that the penguins have to migrate farther to find food. Spending a lot more energy to find food makes penguins less successful at breeding and raising young, the scientists said.

North Atlantic cod. Overfishing has historically caused numbers of this fish to plunge, but its populations usually bounce back. Not so off the northeastern coast of North America, where populations have not recovered since crashing in the 1990s. "The entire ecosystem seems to have changed," the scientists said, and "this may involve a climate influence due to changing ocean currents and the influx of cold Arctic waters." (Read more about overfishing's impact on New England cod.)

Acropora cervicornis and coral worldwide. This reef-building animal "is in decline almost everywhere, for a combination of reasons," said Pörtner, including warming waters-coral are sensitive to changes in ocean temperature. Acropora cervicornis, for instance, used to be widespread in the Caribbean but is now restricted to a few small areas, likely due to warming. (Read more about coral and global warming.)

EXTINCT: Golden toad (Bufo periglenes). Along with the Monteverde harlequin frog (Atelopus varius), also of Central America, the golden toad is among the very small number of species whose recent extinction has been attributed with medium confidence to climate change, according to Scholes and Pörtner. Last seen in 1989, the golden frog lived in mountaintop cloud forests that have disappeared due to drought and other climatic changes. Other confounding factors are involved, such as the deadly chytrid fungus, which has killed off many amphibians worldwide. (See: "Photos: Ten Most Wanted 'Extinct' Amphibians.")

Trying to slow the rate of climate change "is critical for the future of many species," Scholes and Pörtner said.

"To spare many thousands of species, not only do we need to radically reduce greenhouse gas emissions, but we also have to do it soon," they said.

Potential climate change solutions include making vehicles, homes, and buildings more energy efficient and increasing wind and solar power, hydrogen produced from renewable sources, and other alternative energies.

Meanwhile, the world can "greatly assist by reducing the other pressures facing species, principally habitat loss, overharvesting, and pollution; and by ensuring that species have unimpeded pathways for movement."

Follow Christine Dell'Amore on Twitter and Google+.

# data[].attributes.attachment_link.title
7 Species Hit Hard by Climate Change-Including One That's Already Extinct

# data[].attributes.attachment_link.description
Climate change is doing "widespread and consequential" harm to animals and plants, which are struggling to adapt to new conditions, according to a major report released Monday. The report, from the UN's Intergovernmental Panel on Climate Change (IPCC), finds that many life-forms are moving north or into deeper waters to survive as their habitats shift.

# data[].attributes.headline
Climate models questioned: Global warming may be slower than previously thought

# data[].attributes.subject
Climate models questioned: Global warming may be slower than previously thought

# data[].attributes.attachment_link.readable_text
The computers were wrong. There's still hope for Planet Earth.

That's the conclusion of some of the world's leading geoscientists, who conducted a study that found global warming is occurring more slowly than computer models forecast a decade ago.

The study, published in the journal Nature Geoscience, does not contradict the scientists' concerns that global warming is dramatically damaging the environment, but it does suggest that it's not too late to do something about it.

Scientists have long held that a 2-degree Celsius (3.6 degrees Fahrenheit) increase in the earth's temperature would be a tipping point for the environment, and multiple studies have projected that figure to be reached by the end of the century.
DON'T BLAME CLIMATE CHANGE: HURRICANES HAVE ALWAYS BEEN AND WILL ALWAYS BE WITH US
In an effort to prevent a climate catastrophe, the U.N. Framework Convention on Climate Change reached the Paris Agreement in 2015, designed to limit the increase in global temperature to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. That agreement has now been signed by 195 participants and ratified by 162, though the United States has threatened to withdraw its endorsement.

According to global-warming projections collected 10 years ago from 12 separate computer models from universities and government institutes around the world, the planet could emit no more than 70 billion tons of carbon after 2015 to keep temperatures from rising above the 1.5-degree Celsius limit.

But the study in Nature Geoscience suggests that the forecast may not be as dire as the scientists thought.

"We haven't seen that rapid acceleration in warming after 2000 that we see in the models. We haven't seen that in the observations," Myles Allen, professor of geosystem science at the University of Oxford and one of the study's authors, told the Times of London, as reported in The Independent.
SCIENTISTS SAY WARMING MAKES STORMS, LIKE HARVEY, WETTER
The new study shows that another 240 billion tons of carbon emissions can be tolerated.

"That's about 20 years of emissions before temperatures are likely to cross 1.5C," Allen said. "It's the difference between being not doable and being just doable."

Michael Grubb, a professor of international energy and climate change at University College London, and a co-author of the study, said two years ago at the Paris summit that "All the evidence from the past 15 years leads me to conclude that actually delivering 1.5C is simply incompatible with democracy."

But this week he told The Times:"When the facts change, I change my mind, as [John Maynard] Keynes said.

"It's still likely to be very difficult to achieve these kind of changes quickly enough, but we are in a better place than I thought."

# data[].attributes.attachment_link.title
Climate models questioned: Global warming may be slower than previously thought

# data[].attributes.attachment_link.description
The computers were wrong. There's still hope for Planet Earth. That's the conclusion of some of the world's leading geoscientists, who conducted a study that found global warming is occurring more slowly than computer models forecast a decade ago.

# data[].attributes.headline
Climate report: Hottest year, highest greenhouse gas marks, record sea levels

# data[].attributes.subject
Climate report: Hottest year, highest greenhouse gas marks, record sea levels

# data[].attributes.attachment_link.readable_text
* Global land surface temperatures last year were highest in 137 years of record keeping.

* Sea surface temperatures were also at their highest.

* Sea levels were at record highs in the 24 years that satellite record keeping has been used.

* Greenhouse gas marks rose faster than any year and carbon dioxide readings were above a 400 parts per million average for the year for the first time.

NOAA's report pointed out that the heat in 2016 resulted from a strong El Niño early in the year and long-term global warming.

El Niños are weather phenomena that warm the Pacific Ocean and pump lots of excess heat into the atmosphere, raising temperatures.

They are only one factor in the warming of the planet. Climate scientists have said the role of an El Niño is a relatively small one when compared to the role that humans play.

Confirmation of January report

The report confirmed what NOAA, along with the World Meteorological Organization, announced in January about global temperatures.

According to the report released Thursday, the global land and ocean surface temperature was 0.45˚-0.56˚C above the average for 1981 to 2010. The temperature was also more than 1˚C over the pre-industrial average.

The 2015 Paris Climate Agreement set a goal of capping warming at 1.5 degrees over the pre-industrial average.

2016 was the third consecutive year of record warmth, NOAA, an agency in the Commerce Department, said.

The release comes days after news that the authors of a not-yet-released federal report on climate change worry the White House will intervene before their findings can be published. On Monday the New York Times published a previously released draft of the special science section of the National Climate Assessment that is posted online.

CNN was told the version of the draft that is awaiting Trump administration approval has since been revised twice, although the main findings of the report are still in line with the findings in the version of the draft published by the Times.

The authors say their fears are rooted in the overall message emanating from the Trump administration.

"We have yet to see any pushback, there's been no muzzling, but the uncertainly comes from an obvious place," an author of the report who asked not to be named said. "If the administration is backing out of the Paris agreement and there's not a strong backing of the idea of human caused climate change, than our report will most surely come into conflict with some of those stated ideas."

A White House official told CNN it will "withhold comment on any draft report before its scheduled release date."

CNN's Brandon Miller contributed to this report.

# data[].attributes.attachment_link.title
Climate report: Multiple records in 2016

# data[].attributes.attachment_link.description
Global land surface temperatures last year were highest in 137 years of record keeping. * Sea surface temperatures were also at their highest. * Sea levels were at record highs in the 24 years that satellite record keeping has been used.

# data[].attributes.headline
Climate change evidence: How do we know?

# data[].attributes.subject
Climate change evidence: 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.headline
Could climate change get us off the couch? New study says yes.

# data[].attributes.subject
Could climate change get us off the couch? New study says yes.

# data[].attributes.attachment_link.title
Newsela | Climate change may have a small silver lining: more exercise, study says

# data[].attributes.attachment_link.title
Climate Change 101 with Bill Nye | National Geographic

# data[].attributes.attachment_link.title
Climate Change | Educational Video for Kids

# data[].attributes.attachment_link.title
Newsela | Climate change in the U.S. Southwest

# data[].attributes.attachment_link.description
Warmer, drier climate leads to more drought, wildfires, crop losses and health stresses in Southwest.

# data[].attributes.headline
Climate change may have made Louisiana floods more likely

# data[].attributes.subject
Climate change may have made Louisiana floods more likely

# data[].attributes.attachment_link.title
Newsela | Climate change may have made Louisiana floods more likely