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24.How does tree ring growth or lack of growth support or refute climate changes in the last 100 years?

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24.How does tree ring growth or lack of growth support or refute climate changes in the last 100 years?

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Each tree ring tells us what in climate happens in each year. We can figure it out by their color, some tiny spaces, and so on.

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Quite a lot, actually!

But to understand what the trees tell us, we first have to understand the difference between weather and climate.

is a specific event-like a rain storm or hot day-that happens over a short period of time. Weather can be tracked within hours or days. is the average weather conditions in a place over a long period of time (30 years or more).

Scientists at the National Weather Service have been keeping track of weather in the United States since 1891. But trees can keep a much longer record of Earth's climate. In fact, trees can live for hundreds-and sometimes even thousands-of years!

One way that scientists use trees to learn about past climate is by studying a tree's rings. If you've ever seen a tree stump, you probably noticed that the top of the stump had a series of rings. It looks a bit like a bullseye.

These rings can tell us how old the tree is, and what the weather was like during each year of the tree's life. The light-colored rings represent wood that grew in the spring and early summer, while the dark rings represent wood that grew in the late summer and fall. One light ring plus one dark ring equals one year of the tree's life.

Because trees are sensitive to local climate conditions, such as rain and temperature, they give scientists some information about that area's local climate in the past. For example, tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry. If the tree has experienced stressful conditions, such as a drought, the tree might hardly grow at all in those years.

Scientists can compare modern trees with local measurements of temperature and precipitation from the nearest weather station. However, very old trees can offer clues about what the climate was like long before measurements were recorded.

In most places, daily weather records have only been kept for the past 100 to 150 years. So, to learn about the climate hundreds to thousands of years ago, scientists need to use other sources, such as trees, corals, and ice cores (layers of ice drilled out of a glacier).

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What Can Trees Tell Us About Climate Change?

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Tree rings can provide information about past climate!

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23. Droughts and forest fires are on the rise all around the world. lf there's no water for the plants to drink and survive, how can they effectively remove carbon dioxide from the atmosphere?

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23. Droughts and forest fires are on the rise all around the world. lf there's no water for the plants to drink and survive, how can they effectively remove carbon dioxide from the atmosphere?

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There is no way to remove carbon dioxide from the atmosphere because the plants definitely need water to live.

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21. Think of Goldilocks and the Three Bears again. How would you characterize the weather patterns of the United States in the last decade from 2008 - 2018? Very severe weather patterns, very weak weather patterns, or consistently average weather patterns. Consider hurricanes, tornadoes, thunderstorms, flooding events, and droughts. Support with evidence

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21. Think of Goldilocks and the Three Bears again. How would you characterize the weather patterns of the United States in the last decade from 2008 - 2018? Very severe weather patterns, very weak weather patterns, or consistently average weather patterns. Consider hurricanes, tornadoes, thunderstorms, flooding events, and droughts. Support with evidence

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There were still many tornadoes and so on but they were not either good or bad.

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We talk a lot about tornadoes here. While it's not always an egg to chicken type of deal, most tornadoes come after tornado warnings.

That in mind, there are a lot more tornado warnings than tornadoes. In fact, on average, about 2.5 times more. It is true that false alarms and missed tornadoes are still commonplace. But the biggest and the baddest, the ones coming to cause real trouble, are increasingly well predicted.

In any threat environment, there will be more warning than actual threat. It keeps those trained to keep a watchful eye on their toes, and maybe even does the same for the rest of us as well.

There are a lot of ways we could look at warnings. They're a personal interest of mine, but by no means am I am an expert. I covered the innovative way the National Weather Service is implementing #StormWarningTwitter last year over at the Capital Weather Gang. That's a subject I hope to return to soon. In the meantime, there was some playing around to be done with polygons.

I'm going to keep it brief, but everything could use some framing.

Let's start with the image above. It's a generalized representation of where tornado warnings are most expected based on (short and probably biased in spots) history (I'm looking at you northern Arizona). What you see is based of a fairly large grid, which keeps things extra general.
[Americans are getting less advance notice for tornadoes, as researchers struggle to understand why]
It washes out facts like the one in which I live in a tornado warning dead zone in the middle of Washington, D.C. But warnings are relatively frequent in the area. It only goes back to 2008, because that's the first year storm based warnings were nationally implemented. There are storm based warnings prior, but in the interest of keeping it straightforward I am pretending they do not exist. (Iowa Environmental Mesonet has an awesome tool you can play with)

The basic gist of nine years of storm based tornado warnings is that the Mid-South is more or less ground zero for tornado warning frequency. Part of this is the length of the season in that region. In some ways, tornadoes are a constant threat there. While there is a bit of a slumber in summer and fall (unless there are hurricanes), the zone can stay active throughout winter in many years. From there, we see other hot spots in the Midwest and Plains.

Now let's take a look at each year since 2008. I'm going to try to make it a practice to come back here and update this at the end of each year going forward. Fingers crossed. 😉
2008 - 4,701 tornado warnings
Before 2011, there was 2008. Barrages of tornadoes came throughout the 2000s and into the early 2010s, but 2008 and 2011 stand above the rest. By actual numbers, it fell just short of 2011 with 1,688 tornadoes vs. 1,691. On warnings, the difference was just 50, with 2008 taking the top spot at 4,701. A similar ratio. A very red map. Too much death and destruction, but less than there would have been without the NWS effort to save life and property.
2009 - 3,231 tornado warnings
Compared to what we've seen the past few years prior to 2017, this was an active season. In reality, it was more or less average and arguably below average in the typical "tornado alley" of the Plains. Dixie Alley is almost always a tornado warning leader, but this year was particularly stacked in that direction.
2010 - 3,447 tornado warnings
2010 was a big season in spots, and on the high side of average overall when it came to tornadoes. A North Dakota NWS office leading the pack for tornado warnings is unusual in this sample that spans nearly a decade. The northern Plains/Midwest was an area that saw an unusually active tornado season, with several notable outbreaks scouring the landscape.
2011 - 4,651 tornado warnings
"On paper" 2011 and 2008 are virtually tied when it comes to total tornadoes and total tornado warnings. Seasons like these are made at the margins. 2011 ended up with 84 EF3+ tornadoes (23 of which were violent EF4 or EF5 events). 2008 had "only" 59 EF3+ and 10 violent tornadoes. It's those strongest tornadoes that cause the most grief, hence the large gap in deaths (550+ in 2011 and 126 in 2008) between these two terrible years.
2012 - 2,420 tornado warnings
We started this web site and the related adventures five years ago this year. 2012 got off to a big start with outbreaks in February and a major one in March, then another in April. After that? Not a lot. Thanks, ustornadoes.com.
2013 - 1,831 tornado warnings
The biggest tornado outbreak of 2013 didn't come along until November. If the map wasn't enough to tell you it was a fairly quiet year, that fact should help out. The November outbreak was a huge one for the time of year, with 75 tornadoes reported. Other than a two-week period in May in which the infamous Moore (EF5) and El Reno (EF3) tornadoes occurred, the typical hot spots were unusually tornado free.
2014 - 1,873 tornado warnings
2014 picked right up where 2013 left off. This was near the peak of the long-term drought over parts of the Plains, so much of that region was unusually quiet. When storms were not sparse, humidity was not at its typically potent level, leaving supercells with bases way too high to produce tornadoes under rational conditions. Things get a little less rational on the High Plains, and that was one zone which saw tornado warnings fly.
2015 - 2,328 tornado warnings
After a lengthy spell of wondering where tornadoes went, they came back in 2015. A big reason was an energized southern stream as El Nino fueled moisture streamed into the United States. Oklahoma and Texas had crazy flooding through much of the spring. Wherever there is flooding, there are storms. Storms in April and May equals tornadoes. A Christmastime volley of deadly tornadoes capped off the year in an unfortunate way.
2016 - 2,050 tornado warnings
Although drought was mostly dead in the Plains and would eventually be on its way to dying out west, it was another year in a persistent and largely below average stretch. Few if any remarkable events occurred until May arrived. About a week of tornadoes peaked during an outbreak across western Kansas, which helped elevate the Dodge City office on the list for the year.
2008-16 - 26,532 tornado warnings
In the period of 2008 through 2016 much of the country east of the Rockies is colored in some level of ominously-shaded red. Regions of the Mid-South and Gulf Coast saw the most overall warnings during the period.
Possible trends
This is an admittedly small sample to assess trends, especially given the erratic nature of tornado activity year-to-year. As such, there's no point in dedicating a lot of time to it.

A possible takeaway is that we are now seeing fewer tornado warnings to tornadoes. Without examining false alarm and success rates, this may not mean a lot. While there is some evidence that lead times are not as good at they once were, it may be that more quick and weak tornadoes are recorded now than in the past.

As forecasting skill increases, it is logical that there will be fewer tornado warnings that do not result in tornadoes, which should also mean a smaller ratio of warnings to tornadoes.

So far, there have been 934 tornado warnings issued (through April 20) during 2017. Tornado numbers have been running at a top-end pace all year as well, so it will be interesting to see how it continues to progress.

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A look at all the tornado warnings since 2008 (maps) - U.S. Tornadoes

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We talk a lot about tornadoes here. While it's not always an egg to chicken type of deal, most tornadoes come after tornado warnings. That in mind, there are a lot more tornado warnings than tornadoes. In fact, on average, about 2.5 times more. It is true that false alarms and missed tornadoes are still commonplace.

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20. How do El Nino weather patterns influence climate?

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20. How do El Nino weather patterns influence climate?

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EI Nino is the warm phase of the phenomena. it is caused by variations in sea surface temperatures.

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El Nino Impacts along with other Climate Factors That May Influence our Winter Weather

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19. Clouds (water vapor) are considered a greenhouse gas. How can cloud coverage both complicate the heating of Earth and also help alleviate the heating of Earth?

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19. Clouds (water vapor) are considered a greenhouse gas. How can cloud coverage both complicate the heating of Earth and also help alleviate the heating of Earth?

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Clouds cool Earth's surface by reflecting incoming sunlight. Clouds warm Earth's surface by absorbing heat emitted from the surface and re-radiating it back down toward the surface. Clouds warm or cool Earth's atmosphere by absorbing heat emitted from the surface and radiating it to space.

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About ISCCP

Cloud Climatology

In order to predict the climate several decades into the future, we need to understand many aspects of the climate system, one being the role of clouds in determining the climate's sensitivity to change. Clouds affect the climate but changes in the climate, in turn, affect the clouds. This relationship creates a complicated system of climate feedbacks, in which clouds modulate Earth's radiation and water balances.

Clouds cool Earth's surface by reflecting incoming sunlight.

Clouds warm Earth's surface by absorbing heat emitted from the surface and re-radiating it back down toward the surface.

Clouds warm or cool Earth's atmosphere by absorbing heat emitted from the surface and radiating it to space.

Clouds warm and dry Earth's atmosphere and supply water to the surface by forming precipitation.

Clouds are themselves created by the motions of the atmosphere that are caused by the warming or cooling of radiation and precipitation.

If the climate should change, then clouds would also change, altering all of the effects listed above. What is important is the sum of all these separate effects, the net radiative cooling or warming effect of all clouds on Earth. For example, if Earth's climate should warm due to the greenhouse effect, the weather patterns and the associated clouds would change; but it is not known whether the resulting cloud changes would diminish the warming (a negative feedback) or enhance the warming (a positive feedback). Moreover, it is not known whether these cloud changes would involve increased or decreased precipitation and water supplies in particular regions. Improving our understanding of the role of clouds in climate is crucial to understanding the effects of global warming.

Atmospheric scientists have learned a great deal in the past many decades about how clouds form and move in Earth's atmospheric circulation. Investigators now realize that traditional computer models of global climate have taken a rather simple view of clouds and their effects, partly because detailed global descriptions of clouds have been lacking, and partly because in the past the focus has been on short-term regional weather prediction rather than on long-term global climate prediction. To address today's concerns, we need to accumulate and analyze more and better data to improve our understanding of cloud processes and to increase the accuracy of our weather and climate models.

A major effort is under way at the NASA Goddard Institute for Space Studies (GISS) under the direction of Dr. William B. Rossow, to gather better information about clouds and their radiative effects. Since 1983 the International Satellite Cloud Climatology Project (ISCCP), as part of the World Climate Research Program (WCRP), has been collecting observations from weather satellites to assemble a global, multi-year dataset. GISS serves as the Global Processing Center for ISCCP, in cooperation with institutions in several other countries. The datasets provide some of the key variables that determine the interaction of clouds and radiation.

There are now a number of global cloud datasets and datasets available from special field experiments . A thorough study of all these data will take many years and will lead, of course, to new experiments; but the investigations have already provided fresh insights into how clouds might change with climate and provided us with some statistics about the global distribution and character of clouds.

Data collection and model development proceed at GISS in parallel, with the goal of formulating an increasingly precise understanding of how sensitive the climate is in response to external forces and what those changes look like regionally. If we can understand these processes well enough, we may be able to predict the climate of the near-future with sufficient accuracy to be useful for societal planning.

Cloud Climatology: The Role of Clouds in Climate

Clouds have always been signs of the weather to come. Scattered white cumulus clusters sailing across a field of blue promise a dry summer afternoon. Massive dark thunderheads portend crop-damaging wind and rain. A blanket of light gray signals a temperate winter's night. A high sheet of see-through wisps signals a change in the weather tomorrow or the next day. Today meteorologists scan the moving cloud patterns in satellite images to give daily weather forecasts with much greater accuracy than ever before. Special attention to severe weather events like tornadoes with satellite and radar networks has significantly increased the warning time, saving lives.

Thus it is ironic that when it comes to forecasting the climate several decades ahead, clouds mainly obscure our vision. Their most important roles in climate are to modulate Earth's basic radiation balance and to produce precipitation. The law of conservation of energy requires that the energy absorbed by the Earth from the sun balance the energy radiated by the Earth back into space. Clouds both reflect incoming sunlight and inhibit the radiation of heat radiation from the surface, thereby affecting both sides of the global energy balance equation. Clouds also produce precipitation from water vapor, releasing heat to the atmosphere in the process (evaporation of water vapor from the surface cools it, so that these two processes serve to transfer heat from the surface to the atmosphere). Thus, any changes in clouds will modify the radiative energy balance and water exchanges that determine the climate. The trouble is that clouds are produced by the climate, specifically the atmospheric motions (winds) that are produced by the radiative and latent heating influenced by clouds. This connected loop of relations is called a feedback loop. The ways that clouds respond to changes in the climate are so complex that it is hard to determine their net effect on the energy and water balances and to determine how much climate might change.

What makes it so important to disentangle the interactions of clouds and climate? The balance between absorbed solar radiation and emitted heat radiation sets the temperature of Earth. For example, when heat radiation from the surface slows, as caused by increasing greenhouse gas abundances, the balance can only be maintained if the temperature rises. Changing clouds can alter this relation, either increasing or decreasing the magnitude of the resulting temperature increase. Also, when clouds change, precipitation will change, which will affect the supply of freshwater to the land where we live and grow our food. Right now, we do not know how important the cloud-radiative or cloud-precipitation effects are and can not predict possible climate changes accurately.

Cloud Climatology: System of Climate Feedbacks Involving Clouds

To illustrate the complex linkages that clouds are involved in, the figure below represents the climate system as a three-layer atmosphere and a one-layer ocean stretching from the equator (palm tree) to the pole (snow flake). Clouds occur in the lower two atmospheric layers that comprise the troposphere extending from the surface to about 12 km altitude. The uppermost atmospheric layer extends from about 12-100 km and is comprised, going upward, of the stratosphere (containing the ozone layer), the mesosphere and the thermosphere. The fluxes of radiation and water are indicated by different types of arrows: sunlight (red straight arrows), terrestrial (heat) radiation (blue-striped straight arrows), heat carried by atmospheric and oceanic circulations (checkered arrows), water evaporating from the ocean (land) surface (green wiggly arrows) and returning to the surface as precipitation (broken-blue wiggly arrows), water vapor carried by the atmospheric circulation (green wiggly arrows), and freshwater carried by the oceanic circulation (purple wiggly arrows).

The primary energy exchange pathway within Earth's climate system begins withsolar heating of the ocean (and land) surface concentrated towards the equator, continues with transfer of this heat to the atmosphere by the water cycle ocean (and land) surface coolingby evaporation of water and atmospheric heating by precipitation, and ends with atmospheric cooling by emission of infrared radiation to space. Because the heating of the ocean and atmosphere is not uniform over the Earth, circulations are caused in both that transport heat and water: in particular, heat is transported by both the ocean and atmosphere away from the equator and towards the poles. Thus, the concentration of solar heating near the equator is not completely balanced by heat radiation and more heat radiation leaves Earth near the poles than arrives from the sun. The existence of these energy and water transports by the atmosphere and ocean means that the energy and water exchanges by other means do not balance locally.

The atmospheric circulation also produces clouds that modulate both the solar radiation gain and infrared radiation loss and are the locus of precipitation formation, establishing a set of intricately linked feedbacks on any forced climate change. An important consequence of these cloud effects is that time scale for the variation of the energy and water exchanges set by the atmosphere through cloud modulations has a time scale that is very different from the time scale on which the ocean can respond. Thus, the energy and water exchanges also fail to balance over shorter time periods, resulting in unforced variations ofthe climate. Storage of water on land and in ice also contributes to these variations. Study of the climate system to understand its behavior and its sensitivity to imposed perturbations necessarily entails consideration of all these energy and water exchanges, which constitute the main rapid feedbacks. Moreover, these processes create unforced climate variability that also must be understood to separate them from climate changes that might be caused by human activities. None of these energy and water exchanges can be understood without consideration of the effects of clouds on them, so quantitative cloud data, complemented by precipitation, water vapor, and radiative flux data, are required to diagnose these exchanges and their space-time variations.

Cloud Climatology: Net Effect on Energy and Water Balances

At the heart of the difficulty of understanding how clouds affect climatic change is that clouds both cool and heat the planet, even as their own properties are determined by the cooling and heating (current link). The cooling effect is literally visible: the minute water or ice particles in clouds reflect between 30 and 60 percent of the sunlight that strikes them, giving them their bright, white appearance. (Deep bodies of water, such as lakes and oceans, absorb more sunlight than they scatter and so appear very dark. If all of the cloud water in the atmosphere were placed on the surface, the layer depth would only be 0.05 mm on average. If all the water vapor in the atmosphere were reduced to a liquid water layer on the surface, the depth would be about 2 cm on average.) A cloudless Earth would absorb nearly 20 percent more heat from the sun than the present Earth does. To be in radiation balance Earth would have to be warmer by about 12°C (22°F). Thus, clouds can cool the surface by reflecting sunlight back into space, much as they chill a summer's day at the beach.

The cooling effect of clouds is partly offset, however, by a blanketing effect: cooler clouds reduce the amount of heat that radiates into space by absorbing the heat radiating from the surface and re-radiating some of it back down. The process traps heat like a blanket and slows the rate at which the surface can cool by radiation. The blanketing effect warms Earth's surface by some 7°C (13°F). Thus, clouds can heat the surface by inhibiting radiative heat loss, much as they warm a winter's night.

The net effect of clouds on the climate today is to cool the surface by about 5°C (9°F). One can calculate that a higher surface temperature would result from the buildup of greenhouse gases in the atmosphere and the consequent slowing of heat radiation from the surface, provided nothing else changes. But what happens to the radiation balance if, as part of the climatic response, the clouds themselves change?

If the radiative cooling effect of clouds increases more than the heating effect does, the clouds would reduce the magnitude of the eventual warming. The same result could come about if both effects decrease, but the cooling decreases less than the heating does. On the other hand, if the cooling increases less (or decreases more) than the heating, the cloud changes would boost the magnitude of eventual warming. It is also possible for the two effects to go in opposite directions, which would give rise to outcomes similar to the ones already mentioned, but much stronger. In any event, what matters is the difference between the cooling and the heating effects of clouds. For a more detailed and technical discussion, see

Rossow, W.B., and A.A. Lacis, 1990: Global, seasonal cloud variations from satellite radiance measurements. Part II: Cloud properties and radiative effects. J. Climate, 3, 1204-1253.

Rossow, W.B., and Y.-C. Zhang, 1995: Calculation of surface and top of atmosp here radiative fluxes from physical quantities based on ISCCP datasets, 2. Validation and first results. J. Geophys. Res., 100, 1167-1197.

and the references therein.

Clouds are also part of another important internal heat exchange process involving water phase changes. Most of Earth's "free" water is in the oceans (even more water is contained in the rocky crust of Earth), equivalent to a layer covering the whole surface about 2.5 km deep. Another 50 m of water is currently stored in the major ice sheets in Greenland and Antarctica. The atmosphere only contains about 2.5 cm of water and clouds contain only 0.05 mm. When water evaporates from the ocean and land surface, it cools the surface because it takes energy to change liquid/solid water into vapor. The atmospheric circulation transports water vapor from place to place. When the atmospheric motions include upward motions, the air cools and clouds form by condensing water vapor back to liquid/solid form. If the clouds produce no precipitation, then the energy released by the condensation of the cloud water is recaptured by the water vapor when the cloud water evaporates. However, if the clouds produce rain/snow, the energy released by the condensation heats the atmosphere. Because of the atmospheric transport of water vapor, the precipitation does not locally balance the evaporation, so the water vapor transport is equivalent to energy transport. The average evaporation and precipitation rates mean that all the water in the atmosphere is exchanged about once every 10 days. There is also a net transport of about 10% of the total water vapor evaporated from the oceans to the land, most of which is then returned to the oceans by rivers. Thus, the water cycle links the two parts of the radiation balance: the surface is heated by sunlight and cooled by water evaporation, but the atmosphere is heated by precipitation and cooled by terrestrial radiation to space. This water cycle is even more important to us because the small amount of water that is contained lakes and rivers or retained in underground water is our only supply of fresh water for drinking, agriculture and many other industrial and recreational uses.

Cloud Climatology: Greenhouse Effect and Climate Change

Within the next half-century or so an accumulation of airborne pollutants -- notably carbon dioxide (CO2), methane (CH4), nitrous oxides (NOx), and chlorofluorocarbons (CFCs) - will very likely cause noticeable changes in climate ( noticeable changes may have already occurred but there is debate about that). Because these so-called greenhouse gases retard the flow of heat radiation from the surface into space, the whole Earth will warm . This is called the greenhouse effect . This warming is partly reduced by other pollutants that form tiny aerosol particles which reflect some sunlight back to space. The global warming will in turn lead to a variety of other changes throughout Earth's climate system: changes in heat and water transport, wind and ocean currents, precipitation patterns and clouds. Given such a profound potential for an adjustment of the basic climatic elements and the possible consequences for human society, an improved understanding of the radiation and water balance and their dependence on cloud processes is one of several crucial goals of current research.

The threat of climatic change is not primarily in the change itself but in its rapidity. The geological record is replete with climatic changes similar in magnitude to the one now contemplated, but past changes were slow enough to allow most species to adapt. What is unprecedented about the current greenhouse warming is that significant change could come to pass in only a few generations, creating human and economic dislocations. For example, since most people live fairly near oceans, a rapid rise in sea level caused by the melting of glaciers could force most people to move inland. If severe storms, such as hurricanes, became more frequent, they would interfere with airborne and waterbourne transportation of goods from market to consumer. A change in the average temperature and its seasonal variations could alter patterns of energy use and demand. A change in rainfall or snowfall could change our water supply and may alter the success of agriculture . The possible political and economic consequences of such disruptions are suggested by the global concern over maintaining an uninterrupted oil supply from the Middle East or avoiding catastrophic floods and droughts that have affected food supply recently in parts of Africa and Asia.

Yet in spite of the need to forecast climatic changes accurately, current understanding of how the climate works is not detailed enough for climatologists to predict exactly when, where, or to what extent changes will take place, only to say that there will be a certain amount of warming and that other things will likely change. The global climate is such a complex system that no one knows how even a small increase in temperature will alter other aspects of climate or how such alterations will influence the rate of warming. Moreover, changes in any of these climatic features may also affect the distribution and properties of clouds, but the understanding of clouds is so rudimentary that no one knows whether climate feedbacks involving clouds will dampen or amplify a warming trend. The possibility that clouds might accelerate global warming brings a special urgency to the ancient problem of understanding the climatic importance of clouds.
Effects of Global Warming
Cloud Climatology: How Clouds Form and Travel

A cloud is formed when atmospheric water vapor is cooled by vertical air motions (or in the polar regions by heat loss by radiation), condensing on microscopic airborne particles - dust, sea salt, bits of organic matter, or chemical aerosol particles, the most common beingcomposed of sulfuric acid and other sulfate compounds. Between the evaporation of water from the surface and its condensation in a cloud, water vapor is carried along by winds from warmer, moister regions to cooler, drier ones. Because the atmosphere, except for clouds, is nearly transparent to solar radiation, the surface absorbs 70 percent of the total solar heat taken up by the earth-atmosphere system, making the air warmer near the surface than it is at high altitudes. Because sunlight strikes the planet most directly near the equator, the tropics are warmer than the polar regions.

Both temperature gradients - the temperature variations from low to high altitudes and from low to high latitudes - are intensified by the effects of water vapor on radiative heating and cooling and by the transformations of water from liquid or solid into vapor and back. This happens because water vapor is nearly transparent at the wavelengths of sunlight (between 200 and 3,000 nm, nm = nanometer, one billionth of a meter), so it lets virtually all the sunlight reach the surface. However, water vapor is nearly opaque at the wavelengths at which the sunlight-warmed surface radiates away its absorbed energy (thermal radiation with wavelengths between 3,000 and 100,000 nm). The absorption of most of the outgoing thermal radiation by water vapor creates most of Earth's natural greenhouse effect - an effect that is now being increased by human pollution. Without the atmospheric water vapor Earth's surface would be, on average, about 31°C (55°F) colder than it is now and the differences in temperature between high and low altitudes and between the poles and equator would be smaller.

Since cold air is denser than warm air, temperature differences give rise to atmospheric motions that work to eliminate the density differences. Winds generally move warmer, moister air upward and poleward from the tropical surface and move colder, drier air downward and toward the equator from higher altitudes and latitudes. Although some water is transported to higher latitudes at upper levels, the winds nears the equator actually transport water vapor towards the equator, concentrating it into a narrow, heavy rainfall zone there. The contrasts in heating, together with the winds, also drive ocean currents, which help reduce the temperature differences between the equator and the poles even more.

Some of the water evaporated from the surface (primarily from the oceans) condenses into clouds and eventually falls as rain or snow. These transformations not only redistribute water but also play an important role in global heat transport. When surface water evaporates, the heat required to change liquid water into vapor is absorbed from the surface and carried along with the vapor into the air. When water vapor condenses into a cloud and falls as rain, it releases that heat, known as latent heat, into the air.

The processes that control the conversion of water vapor into cloud and precipitation particles are called cloud microphysical processes. The interaction of these processesdetermines the properties of clouds that, in turn, determine the effect of clouds on the radiative energy exchanges, whether the cloud will produce precipitation, how much and what type of precipitation it will produce, and how long the cloud will last.

At temperatures above freezing (0°C), the weak vertical air motions (slow cooling) associated turbulence near the surface or with large-scale circulations lead only to the formation of rather small cloud droplets (about 5-10 µm in radius, 1 micron = 1 millionth meter) covering very large areas. For typical concentrations of small aerosols on which the droplets form (from about 50-200 cm⁻³ over oceans to about 500-2000 cm⁻³ over land), the total amount of vapor converted to droplets is small, equivalent to about a layer of water about 0.01-0.03 mm deep. Such clouds, ranging from scattered fair-weather cumulus toextensive sheets of stratocumulus, produce no precipitation and last only as long as the upward motions continue (usually about 10-20 min for cumulus but days for stratocumulus) because such small droplets fall very slowly (about 3 mm s⁻¹) and evaporate within a fewminutes after the leave the cloud environment. Stronger vertical air motions (rapid cooling as in stormy weather) tends to produce somewhat more numerous and much larger droplets, about 15-30 µm in radius. These larger droplets fall more rapidly (still only about 10 cm s⁻¹) and collide. Colliding droplets merge into even larger, more rapidly falling droplets, so the collision process quickly produces very large droplets, more than 300 µm. Such clouds, ranging from stratus and altostratus to nimbostratus produce drizzle or light rain. When the vertical motions are even stronger, as happens when the heat release from the condensing water causes very rapid ascent of large parcels of air, forming cumulonimbus clouds, the cloud extends into the upper troposphere where the colliding droplets freeze. The mixing of ice and liquid droplets not only produces more rapid growth from the vapor but more efficient sticking of the colliding particles (see discussion below), leading to the growth of very large particles, more than 1 mm (1000 µm) in size, that fall so rapidly (more than 100 m s⁻¹) that they can reach the surface without evaporating. These falling large droplets are known as rainfall; rainfall rates can range from very small rates of 0.01 mm hr⁻¹ to very heavy downpours of 50 mm hr⁻¹.

The situation at colder temperatures is similar to that described above, but there are some important differences that arise because of the peculiar properties of water and because of the difference between liquid and solid particle collisions. Because of the strong interactions of water molecules, some extra energy is needed to initiate the growth of very small water particles from vapor. For the growth of liquid droplets in clouds near the surface, the presence of water-containing aerosol particles greatly reduces the amount of energy needed, requiring only a small excess of vapor pressure over the saturated amount ( i.e., the relative humidity must only reach values of about 100.1% to form droplets). However, at higher altitudes there are not only many fewer aerosols available but they do not help initiate the growth of an ice crystal nearly as well as they can help droplet growth, so ice clouds do not begin to form until the vapor pressure exceeds saturation by a much larger amount (relative humidity with respect to ice usually must reach values as much as 101%). In fact, many ice clouds start instead by forming liquid droplets at temperatures well below freezing(down to as low as about -30°C) and then freezing them. The peculiar property of water is that at temperatures below freezing the saturation vapor pressure over liquid droplets is much higher than over ice crystals at the same temperature. Once these cold droplets begin growing, they quickly freeze, exposing them to a much higher vapor pressure. The consequence is that the ice crystals grow much more quickly to larger sizes in the range from 20-100 µm and they keep growing below the cloud, reaching sizes of a few hundred microns, because the relative humidity is still > 100% with respect to ice below the initial cloud base. These large particles also collide as they fall, but ice crystals have a more difficult time sticking together; nevertheless, at temperatures nearer freezing, some liquid droplets are encountered that help stick the crystals together. So when the air motions are stronger, very much larger frozen particles can be produced. In the violent vertical motions of strong thunderstorms, for example, the particles can fall and rise many times, producing large hail stones that have been known to reach sizes > 10 cm (10 ⁵ µm).

The formation, evolution and motion of clouds is determined by the interaction of these cloud microphysical processes with atmospheric motions and radiation; this combination can be thought of as a kind of cloud dynamics. As the air moves past the particles in a cloud, there is a frictional force exerted, so that, even in very small clouds, the number of particles is sufficient to cause the air to move around the cloud rather than through it. Thus, smaller clouds are moved with the wind. However, since clouds are formed by the air motions, their actual evolution is much more complex and can involve wave as well as mass motions. Differences in the nature and behavior of cloud dynamics in different meteorological situations produces different cloud types. Researchers are now studying the behavior of these different cloud types to understand the role of each in weather and climate.

Cloud Climatology: Computer Climate Models

Because there are so many possibilities for change, climatologists must know how clouds over the entire Earth will respond. Determining that response calls for computer models of the global climate that can explore changing conditions. Climate models are sets of mathematical equations that describe the properties of Earth's atmosphere at discrete places and times, along with the ways such properties can change. The challenge for climate models is to account for the most important physical processes, including cloud microphysics and cloud dynamics, and their complex interactions accurately enough to carry climatic predictions tens of years into the future. When contemporary models are given information about Earth's present condition - the size, shape and topography of the continents; the composition of the atmosphere; the amount of sunlight striking the globe - they create artificial climates that mathematically resemble the real one: their temperatures and winds are accurate to within about 5%, but their clouds and rainfall are only accurate to within about 25-35%. Such models can also accurately forecast the temperatures and winds of the weather many days ahead when given information about current conditions.

Unfortunately, such a margin of error is much too large for making a reliable forecast about climate changes, such as the global warming will result from increasing abundances of greenhouse gases in the atmosphere. A doubling in atmospheric carbon dioxide (CO), predicted to take place in the next 50 to 100 years, is expected to change the radiation balance at the surface by only about 2 percent. Yet according to current climate models, such a small change could raise global mean surface temperatures by between 2-5°C (4-9°F), with potentially dramatic consequences. If a 2 percent change is that important, then a climate model to be useful must be accurate to something like 0.25%. Thus today's models must be improved by about a hundredfold in accuracy, a very challenging task. To develop a much better understanding of clouds, radiation and precipitation, as well as many other climate processes, we need much better observations.

Cloud Climatology: Simple Early Views of Clouds

The earliest attempts to predict how changes in cloud cover would affect greenhouse warming concluded that they would have no net effect: clouds would neither speed nor slow a change in climate. That conclusion was based on the belief that any change that made clouds better at cooling the Earth would also make them more efficient at retaining heat near the surface. For example, if cloud cover were to increase (as many thought it would, assuming that warmer temperatures would speed evaporation), the amount of sunlight reaching Earth's surface would decrease, but then the thermal radiation trapped by the cloud might increase by the same amount.

Even such a simple scenario has problems, though. Because the decrease in solar heating would affect surface temperatures, whereas the change in the emission of thermal radiation would affect air temperatures at higher altitudes, additional cloud cover would reduce the temperature contrasts between the surface and the higher altitudes that drive the winds. Any reduction of winds might in turn inhibit the formation of clouds. The early studies did not account for this possibility.

Another idea is that higher atmospheric temperatures could create denser clouds, since greater evaporation rates at higher temperatures would make more water vapor available in the atmosphere for cloud condensation. Because denser clouds reflect more sunlight, there would be an enhanced cooling effect. This would reduce the magnitude of the greenhouse warming. On the other hand, denser clouds might also lead to an increase in precipitation (rainfall and snowfall), possibly from storm clouds, whose tops are especially high and cold. Such clouds, which are particularly good absorbers of thermal radiation, could more than make up for their tendency to block sunshine. In that case the warming would be intensified. Observations have shown, however, that warmer temperatures seems to create less dense, low-level clouds instead. The evidence we have so far suggests that this effect occurs because, as temperature increases, the air near the surface becomes drier, causing the cloud base to rise and reducing the cloud layer thickness. Earlier studies did not consider this possibility.

Such "what-if" discussions can go on indefinitely. All of the changes mentioned above are physically reasonable and there are many more to be considered. The question is: How many and which ones will actually take place when the climate changes and exactly how large will they be? In all likelihood, all of these changes and more would occur together, but we don't know what the net effect would be.

Another kind of complication is that clouds come in many forms , depending on the weather conditions that create them. Low, dense sheets of stratocumulus clouds hanging just above the ocean cool more than they heat. They make efficient shields against incoming sunlight, and because they are low - and therefore warm - they radiate upward almost as much thermal radiation as the surface does. In contrast, the thin, wispy cirrus clouds, which soar at 6,000 meters (20,000 feet) and higher, reflect little sunlight, but they are so cold that they absorb most of the thermal radiation that comes their way. Hence they warm more than they cool. The net cooling effect of clouds is the sum of a large number of such specific effects, many of which cancel one another.

Atmospheric scientists have been aware for nearly two decades that the complex effects of clouds on radiation and water exchanges pose a major challenge to the understanding of climatic change. In 1974 an international conference of investigators in Stockholm highlighted the need for greater understanding of clouds as one of the two biggest obstacles to further progress in climate research. The second was inadequate knowledge of ocean currents. Recent comparisons of the predictions made by various computer climate models show that the problem has not gone away. In some models, for instance, clouds decrease the net greenhouse effect, whereas in others they intensify it.

Cloud Climatology: How Clouds Might Change with Global Warming

Although simple relations may hold between climatic conditions and the radiative properties of certain kinds of cloud, predicting how the global distribution of various kinds of clouds would change with global warming is complicated by their interaction with regional wind systems. Consider the roles of clouds in seasonal climatic change. In the midlatitudes, winter brings a substantial decline in solar heating, yet the corresponding drop in air temperature near the surface is between 70 and 80 percent less than what the decline in solar heating would seem to imply. More abundant and thicker winter clouds, with slightly higher tops, trap heat better.

In the tropics, despite significantly greater cloud cover in the rainy season, there is only a small seasonal variation in surface temperature. In part the variation is small because the effects of tropical clouds on thermal and solar radiation nearly cancel one another, but even more important is the controlling influence of heat transports by atmospheric winds.

The quest for more data about clouds and climate continues in parallel with the refinement of climate models. It is a slow-going process: each new piece of information must be incorporated throughout. With certain findings the models themselves may have to be reformulated. But the result should be an increasingly precise understanding of how sensitive the clouds are in response to changes in external forces and what effect those changes would have on global warming. One must hope that the model building and data collection activities will lead to an understanding of climatic change before that change comes to pass.

Cloud Climatology: Global Distribution and Character of Clouds

The new global datasets show that clouds typically cover almost two-thirds of the planet, some 10 percent more than had been thought. Oceans are significantly cloudier than continents. Slightly more than 70 percent of the sky over oceans is cloudy, but a little less than 60% of the total land area is usually covered with clouds. Almost a fifth of the continental surface is covered by large areas of clear sky, whereas less than 10 percent of the ocean surface is. Clouds on average are about 27°C (48°F) colder than the surface is, and they reflect more than twice the amount of sunlight as the surface. But far more interesting than such averages is how widely the properties of clouds can vary with location, with time of day, with changing weather, and with season).

Cloud over the ocean, for instance, are different in some ways from clouds over land. The tops of ocean clouds are generally slightly more than a kilometer (3300 feet) lower than the tops of clouds over land, but ocean clouds reflect about 3% more sunlight on average than clouds over land. Above the oceans at low latitudes, clouds are more common in the morning than in the afternoon and the morning clouds are the most reflective of the day. Over land there are more clouds, with higher reflectivity, in the afternoon. Although clouds over oceans and land contain about the same amount of water on average, the low-level clouds over oceans are composed of fewer, but larger, droplets than are low-level clouds over land.

Cloud properties also vary with distance from the equator. The cloudiest regions are tropics and the temperate midlatitude storm zones; the subtropics and the polar regions have 10-20% less cloud cover. Tropical cloud tops are substantially higher, on average extending between one and two kilometers higher than cloud tops in the midlatitudes and more than two kilometers higher than the clouds over the subtropics and the north pole (clouds are much higher on average over the south pole because the ice sheet surface is so much higher in altitude). At some places in the tropics (the western Pacific Ocean, the Amazon River Basin and the Congo River Basin), cloud tops extend up to 15 kilometers (50,000 feet), occasionally higher. High-latitude clouds are almost twice as reflective as most clouds at lower latitudes.

Any attempt to explain such variations must take into account the kinds of clouds common to a given region, which depends on the local meteorology. Consider storm clouds. In the tropics exceptionally large thunderheads often form, extending from the surface to an altitude of between twelve and fifteen kilometers (about 40,000-50,000 feet). Similar storm clouds occur in areas of low pressure over temperate regions, but their tops only reach altitudes of between seven and ten kilometers (about 23,000 - 33,000 feet). Elsewhere thunderheads are virtually absent. To understand clouds better, scientists are investigating the detailed behavior of many different cloud types as defined by surface weather observers and cloud types as defined by weather satellites.

Meteorologists have long associated greater cloud cover, higher cloud tops and denser, more reflective clouds with regions of more vigorous storms. Both the tropics and the low-pressure areas at midlatitudes are regions of severe weather. The frequency and strength of storms are also related to such climatic factors as average wind speed and direction, temperature, humidity, sunlight and topography. By comparing satellite observations of cloud variations with meteorological data, it may be possible to establish correlations between these conditions and the cooling and heating properties of clouds.
Cloud Microphysics Further Reading

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In order to predict the climate several decades into the future, we need to understand many aspects of the climate system, one being the role of clouds in determining the climate's sensitivity to change. Clouds affect the climate but changes in the climate, in turn, affect the clouds.

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22.Carbon dioxide has been associated with the warming of Earth. You have learned in Biology class that carbon dioxide in the atmosphere is taken out of the air by plants and trees through photosynthesis and replaced with breathable oxygen.          a. Does this statement support global warming deniers? Explain.                                       b. Does this statement support climate science research? Explain.                                       c. Does your answer change when you consider deforestation and increased demand for paper and housing?

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22.Carbon dioxide has been associated with the warming of Earth. You have learned in Biology class that carbon dioxide in the atmosphere is taken out of the air by plants and trees through photosynthesis and replaced with breathable oxygen.          a. Does this statement support global warming deniers? Explain.                                       b. Does this statement support climate science research? Explain.                                       c. Does your answer change when you consider deforestation and increased demand for paper and housing?

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a. Yes, it does. Because simply the global warming will stop if the amount of carbon dioxide decreases.
b. Yes, it does. Because the plants are definitely related to the climate and the global warming.
c. My opinion is still the same that we have to save as many plants as possible. In order to do this, we should plant in the vacant lot.

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18. How does carbon dioxide trap infrared radiation on Earth?

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18. How does carbon dioxide trap infrared radiation on Earth?

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CO2 absorbs radiations and sends it out.

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Molecules of carbon dioxide (CO₂) can absorb energy from infrared (IR) radiation. This animation shows a molecule of CO ₂ absorbing an incoming infrared photon (yellow arrows). The energy from the photon causes the CO ₂ molecule to vibrate. Some time later, the molecule gives up this extra energy by emitting another infrared photon. Once the extra energy has been removed by the emitted photon, the carbon dioxide molecule stops vibrating.

This animation is somewhat of a simplification. Molecules are constantly in motion, colliding with other gas molecules and transferring energy from one molecule to another during collisions. In the more-complex, real-world process, a CO ₂ molecule would most likely bump into several other gas molecules before re-emitting the infrared photon. The CO ₂ molecule might transfer the energy it gained from the absorbed photon to another molecule, adding speed to that molecule's motion. Since the temperature of a gas is a measure of the speed of the molecules in the gas, the faster motion of a molecule that eventually results from the IR photon that was absorbed by a CO ₂ molecule raises the temperature of the gases in the atmosphere.

Do all gas molecules absorb and re-emit infrared energy?

This ability to absorb and re-emit infrared energy is what makes CO ₂ an effective heat-trapping greenhouse gas. Not all gas molecules are able to absorb IR radiation. For example, nitrogen (N ₂) and oxygen (O ₂), which make up more than 90% of Earth's atmosphere, do not absorb infrared photons. CO ₂ molecules can vibrate in ways that simpler nitrogen and oxygen molecules cannot, which allows CO ₂ molecules to capture the IR photons.

Greenhouse gases and the greenhouse effect play an important role in Earth's climate. Without greenhouse gases, our planet would be a frozen ball of ice. In recent years, however, excess emissions of carbon dioxide and other greenhouse gases from human activities (mostly burning fossil fuels) have begun to warm Earth's climate at a problematic rate. Other significant greenhouse gases include water vapor (H ₂O), methane (CH ₄), nitrous oxide (N ₂O) and ozone (O ₃).

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Carbon Dioxide Absorbs and Re-emits Infrared Radiation

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Molecules of carbon dioxide (CO2) can absorb energy from infrared (IR) radiation. This animation shows a molecule of CO 2 absorbing an incoming infrared photon (yellow arrows). The energy from the photon causes the CO 2 molecule to vibrate. Some time later, the molecule gives up this extra energy by emitting another infrared photon.

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17. Why is there less heat escaping into space?

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17. Why is there less heat escaping into space?

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Because greenhouse gases cover the Earth so the heat cannot escape.

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16.What are sea surface temperatures (SST)? Think of Goldilocks and the Three Bears...are SSTs too hot, too cold, or are they just right? Explain.

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16.What are sea surface temperatures (SST)? Think of Goldilocks and the Three Bears...are SSTs too hot, too cold, or are they just right? Explain.

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Sea Surface Temperature (SST) is a measure of the energy due to the motion of molecules at the top layer of the ocean.
Too hot because they have been rising.
Sea surface temperature increased during the 20th century and continues to rise. From 1901 through 2015, temperature rose at an average rate of 0.13°F per decade (see Figure 1).

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Key Points

Sea surface temperature increased during the 20th century and continues to rise. From 1901 through 2020, temperature rose at an average rate of 0.14°F per decade (see Figure 1).

Sea surface temperature has been consistently higher during the past three decades than at any other time since reliable observations began in 1880 (see Figure 1).

Based on the historical record, increases in sea surface temperature have largely occurred over two key periods: between 1910 and 1940, and from about 1970 to the present. Sea surface temperature appears to have cooled between 1880 and 1910 (see Figure 1).

Changes in sea surface temperature vary regionally. While most parts of the world's oceans have seen temperature rise, a few areas have actually experienced cooling-for example, parts of the North Atlantic (see Figure 2).

Background

Sea surface temperature-the temperature of the water at the ocean surface-is an important physical attribute of the world's oceans. The surface temperature of the world's oceans varies mainly with latitude, with the warmest waters generally near the equator and the coldest waters in the Arctic and Antarctic regions. As the oceans absorb more heat, sea surface temperature increases, and the ocean circulation patterns that transport warm and cold water around the globe change.

Changes in sea surface temperature can alter marine ecosystems in several ways. For example, variations in ocean temperature can affect what species of plants, animals, and microbes are present in a location, alter migration and breeding patterns, threaten sensitive ocean life such as corals, and change the frequency and intensity of harmful algal blooms such as "red tide." Over the long term, increases in sea surface temperature could also reduce the circulation patterns that bring nutrients from the deep sea to surface waters. Changes in reef habitat and nutrient supply could dramatically alter ocean ecosystems and lead to declines in fish populations, which in turn could affect people who depend on fishing for food or jobs.

Because the oceans continuously interact with the atmosphere, sea surface temperature can also have profound effects on global climate. Increases in sea surface temperature have led to an increase in the amount of atmospheric water vapor over the oceans. This water vapor feeds weather systems that produce precipitation, increasing the risk of heavy rain and snow (see the Heavy Precipitation and Tropical Cyclone Activity indicators). Changes in sea surface temperature can shift storm tracks, potentially contributing to droughts in some areas. Increases in sea surface temperature are also expected to lengthen the growth season for certain bacteria that can contaminate seafood and cause foodborne illnesses, thereby increasing the risk of health effects.

About the Indicator

This indicator tracks average global sea surface temperature from 1880 through 2020. It also includes a map to show how change in sea surface temperature has varied across the world's oceans since 1901.

Techniques for measuring sea surface temperature have evolved since the 1800s. For instance, the earliest data were collected by inserting a thermometer into a water sample collected by lowering a bucket from a ship. Today, temperature measurements are collected more systematically from ships, as well as at stationary and drifting buoys.

The National Oceanic and Atmospheric Administration has carefully reconstructed and filtered the data in Figure 1 to correct for biases in the different collection techniques and to minimize the effects of sampling changes over various locations and times. The data are shown as anomalies, or differences, compared with the average sea surface temperature from 1971 to 2000. The map in Figure 2 was originally developed by the Intergovernmental Panel on Climate Change, which calculated long-term trends based on a collection of published studies.

About the Data

Indicator Notes

Both components of this indicator are based on instrumental measurements of surface water temperature. Due to denser sampling and improvements in sampling design and measurement techniques, newer data are more precise than older data. The earlier trends shown by this indicator have less certainty because of lower sampling frequency and less precise sampling methods.

Data Sources

Data for Figure 1 were provided by the National Oceanic and Atmospheric Administration's National Centers for Environmental Information and are available online at: https://www.ncei.noaa.gov/products/extended-reconstructed-sst. These data were reconstructed from measurements of water temperature, which are available from the National Oceanic and Atmospheric Administration at: https://icoads.noaa.gov/products.html. Figure 2 is an updated version of a map that appeared in the Intergovernmental Panel on Climate Change's Fifth Assessment Report ( www.ipcc.ch/report/ar5/wg1), which gathered data from a variety of studies that provide the best available information about climate change.

Technical Documentation

References
1. For example, see: Ostrander, G.K., K.M. Armstrong, E.T. Knobbe, D. Gerace, and E.P. Scully. 2000. Rapid transition in the structure of a coral reef community: The effects of coral bleaching and physical disturbance. P. Natl. Acad. Sci. USA. 97(10):5297-5302. 2. Pratchett, M.S., S.K. Wilson, M.L. Berumen, and M.I. McCormick. 2004. Sublethal effects of coral bleaching on an obligate coral feeding butterflyfish. Coral Reefs 23(3):352-356. 3. Pershing, A.J., R.B. Griffis, E.B. Jewett, C.T. Armstrong, J.F. Bruno, D.S. Busch, A.C. Haynie, S.A. Siedlecki, and D. Tommasi. 2018. Oceans and marine resources. In: Impacts, risks, and adaptation in the United States: Fourth National Climate Assessment, volume II. Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.). doi:10.7930/NCA4.2018.CH9.

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Climate Change Indicators: Sea Surface Temperature | US EPA

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This indicator describes global trends in sea surface temperature.

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15. What is ocean acidification? How has this influenced our oceans over the last 100 years?

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15. What is ocean acidification? How has this influenced our oceans over the last 100 years?

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CO2 makes ocean more acidic.

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Because sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.

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14.If the glaciers melt, where does most of that liquid (freshwater) go? (ls ocean water drinkable?Can ocean water be used to irrigate crops for 7 billion Earthlings?)

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14.If the glaciers melt, where does most of that liquid (freshwater) go? (ls ocean water drinkable?Can ocean water be used to irrigate crops for 7 billion Earthlings?)

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The water turns into the river through the ice.
We cannot drink ocean water. Also ocean water cannot be used for farms because it is salty.

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On Greenland's vast ice sheet, meltwater flows in rivulets as sunlight and warm air heat the surface ice.

Surface variations create thousands of low-lying areas where meltwater collects and eventually drains.

The rivulets drain into larger rivers that carve natural paths across the ice sheet.

Over years, impurities in the ice become concentrated, making it darker. Those areas absorb more sunlight, causing more melting.

Underneath the surface, the ice develops holes, like swiss cheese.

This river reached a large depression in the ice and formed a lake.

The lake fed another fast-moving river on the opposite side.

That river disappeared down a hole in the ice, called a moulin.

Sea level rise depends on how much water drains from the ice sheet into the ocean, and how fast.

New research suggests that more of the water may be trapped inside the ice sheet than previously thought.

On Greenland's vast ice sheet, meltwater flows in rivulets as sunlight and warm air heat the surface ice.

Surface variations create thousands of low-lying areas where meltwater collects and drains.

The rivulets drain to larger rivers that carve natural paths across the ice sheet.

Over years, impurities in the ice become concentrated, making it darker. Those areas absorb more heat, and cause greater melting.

This river reached a depression in the ice and formed a lake, which fed another river on the opposite side.

That river disappeared down a hole in the ice, called a moulin.

Sea level rise depends on how much water drains from the ice sheet into the ocean. New research suggests there may be more water trapped in the ice than previously thought.

In the summer of 2015, two New York Times journalists joined a team of researchers in Greenland that was conducting a unique experiment: directly measuring a river of meltwater runoff on the top of the ice.

Now, the scientists have published the results of that work. A key finding - that not as much meltwater flows immediately through the ice sheet and drains to the ocean as previously estimated - may have implications for sea-level rise, one of the major effects of climate change.

The scientists say it appears that some of the meltwater is retained in porous ice instead of flowing to the bottom of the ice sheet and out to sea.

"It's always treated as a parking lot, water runs straight off," said Laurence C. Smith, a geographer at the University of California, Los Angeles who led the field work in 2015. "What we found is that it appears there is water retention."

"It's plausible that this is quite an important process, which could render sea-level projections too high," he added.

There's still much that remains unknown about the ice sheet, which at roughly 650,000 square miles is more than twice the size of Texas. The sheet, up to two miles thick, contains enough ice that, if it all melted, would raise oceans around the world by 24 feet. Precisely how the ice melts - half or more by warming on the surface, the rest by ice sheet movement toward the sea, where it melts or calves off as icebergs - can greatly affect how much and how fast the seas rise.

Greenland is currently losing an average of about 260 billion tons of ice per year; at this rate, it would contribute about two inches to sea level rise by the end of the century. This ice loss is estimated through gravity measurements by satellites, but computer models that simulate physical processes are used to estimate the surface runoff. The field study was meant to improve those models by providing on-the-ground data on the flow of meltwater.

The work involved setting up camp near a glacial river that drains meltwater from a surrounding catchment area - in this case about 24 square miles of the ice sheet - into a moulin, a hole that drains to the base of the ice sheet. The researchers suspended a device in the river that uses acoustic signals to gauge the flow, and used satellite and drone images to precisely calculate the catchment area.

The flow data, collected over 72 hours, showed that current models are overestimating the amount of runoff by 20 percent to nearly 60 percent. Were the models wrong? Or were they right about the total amount of melting, but some of the water was not running off?

When he first sent the results to modelers, Dr. Smith said, "they couldn't believe it." After months of back-and-forth, Dr. Smith and his colleagues concluded that the model estimates were accurate, but there was something else going on with some of the meltwater. "What is missing," he said, "is a physical process that is not currently considered by the models - water retention in ice."

Sunlight hitting the ice sheet melts the surface, Dr. Smith said, but some of the light reaches deeper into the ice and causes some melting there. The ice develops a rotted, porous texture -- and can, the findings suggest, hold on to some of the meltwater.

The New York Times | Source: Satellite imagery by DigitalGlobe via Laurence Smith at the University of California, Los Angeles

Marco Tedesco, a co-author of a paper on the work in The Proceedings of the National Academy of Sciences who is a modeler at Lamont-Doherty Earth Observatory, part of Columbia University, said when comparing models with actual field measurements, "you always look at the energy involved."

"If there's a mismatch between observation and model," Dr. Tedesco said, "that means the model is moving the mass in one way or another and not respecting the way things happen in the real world."

Further work on the ice sheet will try to directly measure how much water is retained in the ice. More direct flow measurements are needed as well, as conditions can vary greatly over the huge icecap. (As the original Times article revealed, gauging stream flow on an ice sheet is far more complicated and dangerous than doing it on land.)

But surface runoff is only one area where much remains to be learned. What happens at the bottom of the ice when meltwater reaches it is understood largely through modeling, and those processes can affect how fast the ice sheet moves - and thus how much ice calves off into the ocean.

Among other aspects that scientists are studying is bioalbedo, which is how the growth of microorganisms in the ice can darken the surface and affect how fast it melts.

Thomas P. Wagner, a program scientist at NASA who directs the agency's efforts to study polar regions, said that studies like Dr. Smith's - and research on the far larger Antarctic ice sheet - are critical to understanding how climate change will affect the globe.

"Sea level rising is 3 millimeters a year right now," Dr. Wagner said. "But in a hundred years, we could have one to five feet of rise."

"Everyday we are improving our understanding of how ice is getting into the ocean," he added. "The overall context is, we're on this."

Note: The image at the top comes from drone photos collected by Jonathan Ryan at the University of California, Los Angeles, and Brown University; and Alun Hubbard at Aberystwyth University in Wales.

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As Greenland Melts, Where's the Water Going?

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On Greenland's vast ice sheet, meltwater flows in rivulets as sunlight and warm air heat the surface ice. Surface variations create thousands of low-lying areas where meltwater collects and eventually drains. The rivulets drain into larger rivers that carve natural paths across the ice sheet.

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12. What can ice cores tell us about the history of Earth's climate over time? How far back in time can ice cores provide information?

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12. What can ice cores tell us about the history of Earth's climate over time? How far back in time can ice cores provide information?

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Scientists will tell us that ice cores offer direct climate information. Ice cores are a sample of layers of snow and ice that have collected over a period of a series of years that offers a continuous record of events and conditions. Falling snow captures the atmosphere through which it travels, collecting the chemistry, particles and compounds that are present - these include bits of dust, trace metals, or radioactivity.
Ice cores can go back to si million years ago.

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Project Overview Logistics Equipment Antarctic Information Gamburtsev Mountains Subglacial Lakes Ice Cores

Greenland Test Season
Meet the People Education Outreach Events Blogs & Stories Research Press
EXTERNAL LINKS

British Antarctic Survey
Australian Antarctic Division GAMSEIS US IPY IPY

What is a core and how is it collected?

Photo Credits:Kendrick Taylor, DRI, University of Nevada-RenoImage source http://www.ncdc.noaa.gov/paleo/slides/slideset/

Collecting a core refers to cutting and removing a cylindrical section of a sample or substance, much like coring an apple involves taking a cylindrical section of the apple. The coring is done so that the section of material sampled is not crushed or compressed, but 'cut' in a fairly intact manner, retaining original layering and positioning.

In studying the Earth many different types of cores are collected, each type offering a different kind of information about the Earth and its history. Some scientists collect sediment cores from the bottom of the ocean using long hollow tubes, which are pushed into the sediment collected on the ocean floor. Other scientists collect rock cores by drilling a hollow metal tube into the Earth and removing a section of rock. And still other scientists drill into layers of ice to collect long cylindrical sections of accumulated ice. The image to the left shows the bottom of an ice drill; the cutter head (the part that cuts the ice) and the core barrel, (the hollow tube that follows the cutter head to capture and hold the ice as it is extracted.)

Each of these types of cores represents a glimpse into the past; a layered collection of information about past climates, Earth processes and major events. In examining a core it is important to recognize that older information will be buried deeper down in the core (the geologic principle of 'superposition'). The closer to the surface you travel up a core, the closer the events, or time represented, are to the present. Think of the core as a vertical scale, the higher you climb up the scale the more recent the information. In order to determine just how much time is represented in a core, precise analysis and chemical testing is done.

What can we learn from an ice core?

Scientists travel to the ends of the Earth to gather ice cores...but why? Scientists will tell us that ice cores offer direct climate information. Ice cores are a sample of layers of snow and ice that have collected over a period of a series of years that offers a continuous record of events and conditions. Falling snow captures the atmosphere through which it travels, collecting the chemistry, particles and compounds that are present - these include bits of dust, trace metals, or radioactivity. In extreme climates the snow remains all year, with each year's snow contribution being sealed with each subsequent year's snow accumulation. This means that all this information trapped in the snow is being captured and sealed in place.

As snow is layered it compresses, and over time the lower layers are turned into ice, capturing small samples of the atmosphere as air bubbles. These natural ice archives with trapped chemicals, dust and air, can hold a a tremendous amount of information for scientists. Past climates and temperatures, large scale Earth events such as volcanic eruptions, atmospheric changes, ice accumulation rates over time, changes in vegetation and human impacts on the overall Earth system through emissions of gases and chemicals are all information that is captured in ice cores. Scientists can use other methods to try and determine past climates, but ice cores provide continuous, direct, high resolution information which can provide annual, as well as seasonal information. The image shown above is an example of seasonal and annual ice layering within an ice core. This 19 cm section of a Greenland ice core (GISP 2) was extracted from a depth of 1855 m. This ice section contains 11 annual layers, which are illuminated with special lighting to show the narrower summer layers (farrowed) sandwiched between darker wider winter layers.
How does an ice core relate to this project?

Image from the following article:
Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2; Robert M. DeConto and David Pollard; Nature 421, 245-249(16 January 2003); doi:10.1038/nature01290

While the majority of partners involved in this project are focused on airborne geophysical measures of the area, the Chinese have completed several overland traverses by tractor to the project site, Dome A. They plan to construct a science research base in this area and complete a series of studies, including drilling the Earth's oldest ice core, in order to examine climate history for the last 1.2 to 1.5 million years. Where is the best place to drill this ice core?

Glaciers begin to form in areas where there is sufficient snow, and the area is cold enough for snow to remain on the ground year-round. If each year the new snow amounts exceed any melt that occurs, layers of snow gradually accumulate compressing into ice. Each year's snowfall contributes to a growing glacier. Glaciers develop in mountains as temperature decreases with elevation, so the Gamburtsev Mountains would be an expected origin for the glacier that developed into the Antarctic Ice Sheet.

Scientific models are ways that scientists can look at possible explanations for large scale processes that they can't directly observe. Scientists have modeled ice formation in East Antarctica as it transitioned from a more temperate environment to an icy continent. The graphic series shown here is from DeConto and Pollard. It shows a modeled progression of ice build up on the continent starting some 34,000,000 years ago. The model suggests that ice began to build in three sections of East Antarctica - Dronning Maud Land, the Gambertsev Mountains and the Transantarctic Mountains. After the model progresses for 300,000 years the ice sheet approximates present conditions, covering the majority of the continent, with the deepest and oldest section of ice still located over the Gamburtsev Mountains.

Currently there is limited data for this area of East Antarctica because it is so difficult to access, but we do have information on the age of the ice in one critical location...Lake Vostok. Lake Vostok, lies East of the Gamburtsev Mountains. Lake Vostok ice cores and radar data has been the focus of international study for several years. By flying a series of long flight lines between Lake Vostok and the Gamburtsev Mountains we can connect the radar data from this missing interior area to Lake Vostok's existing data. This data will be available to assist China in selecting where to drill their ice core.

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Project Overview Logistics Equipment Antarctic Information Gamburtsev Mountains Subglacial Lakes Ice Cores Greenland Test Season Meet the People Education Outreach Events Blogs & Stories Research Press EXTERNAL LINKS British Antarctic Survey Australian Antarctic Division GAMSEIS US IPY IPY What is a core and how is it collected?

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13. How have sea levels fluctuated over the last several thousand years? ls this driven by natural circumstances or is this caused by human influence. In your opinion, why?

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13. How have sea levels fluctuated over the last several thousand years? ls this driven by natural circumstances or is this caused by human influence. In your opinion, why?

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The two major causes of global sea level rise are thermal expansion caused by warming of the ocean (since water expands as it warms) and increased melting of land-based ice, such as glaciers and ice sheets. The oceans are absorbing more than 90 percent of the increased atmospheric heat associated with emissions from human activity.
In my opinion, this is because of human activities. People use a lot of chemical things which is not good for the Earth at all.

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Global sea level has been rising over the past century, and the rate has increased in recent decades. In 2014, global sea level was 2.6 inches above the 1993 average-the highest annual average in the satellite record (1993-present). Sea level continues to rise at a rate of about one-eighth of an inch per year.

Higher sea levels mean that deadly and destructive storm surges push farther inland than they once did, which also means more frequent nuisance flooding. Disruptive and expensive, nuisance flooding is estimated to be from 300 percent to 900 percent more frequent within U.S. coastal communities than it was just 50 years ago.

The two major causes of global sea level rise are thermal expansion caused by warming of the ocean (since water expands as it warms) and increased melting of land-based ice, such as glaciers and ice sheets. The ocean is absorbing more than 90 percent of the increased atmospheric heat associated with emissions from human activity.

With continued ocean and atmospheric warming, sea levels will likely rise for many centuries at rates higher than that of the current century. In the United States, almost 40 percent of the population lives in relatively high-population-density coastal areas, where sea level plays a role in flooding, shoreline erosion, and hazards from storms. Globally, eight of the world's 10 largest cities are near a coast, according to the U.N. Atlas of the Oceans.

Sea level rise at specific locations may be more or less than the global average due to local factors such as land subsidence from natural processes and withdrawal of groundwater and fossil fuels, changes in regional ocean currents, and whether the land is still rebounding from the compressive weight of Ice Age glaciers. In urban settings, rising seas threaten infrastructure necessary for local jobs and regional industries. Roads, bridges, subways, water supplies, oil and gas wells, power plants, sewage treatment plants, landfills-virtually all human infrastructure-is at risk from sea level rise.

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national oceanic and atmospheric administration

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Global sea level has been rising over the past century, and the rate has increased in recent decades. In 2014, global sea level was 2.6 inches above the 1993 average-the highest annual average in the satellite record (1993-present). Sea level continues to rise at a rate of about one-eighth of an inch per year.

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11. Find a graphic of human-influenced carbon dioxide emissions and the atmospheric concentration of carbon dioxide. Do the graphs you found look like hockey sticks? Explain.

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11. Find a graphic of human-influenced carbon dioxide emissions and the atmospheric concentration of carbon dioxide. Do the graphs you found look like hockey sticks? Explain.

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Yes, they do. Both of the graphs are going up together.
(This picture is from https://www.skepticalscience.com/co2-increase-is-natural-not-human-caused.htm)

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10.How does an increasing consumption of and demand for fish in a human's diet relate to carbon emissions?

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10.How does an increasing consumption of and demand for fish in a human's diet relate to carbon emissions?

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seafood has a smaller carbon footprint than other animal proteins, but even among seafood, fish and shellfish can have varying impacts.

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Food is expensive. Not just for pocketbooks, but for the planet. Worldwide, more than 25 percent of greenhouse gas emissions come from food production. That's methane belched from cows and nitrous oxide escaping from soils, as well as fossil fuels burned by tractors, fishing boats and rumbling transport vehicles. Some foods cost more than others.

Seafood has a smaller carbon footprint than other animal proteins, on average, because fishing doesn't require farmland or care of livestock. But even among seafoods, fish and shellfish can have varying impacts.

So what's the best choice? Small schooling species, like anchovies and herring, are the most sustainable options, experts say, based on energy use and emissions of their fisheries. There's no free lunch. The question is, what can the planet afford?

Small schooling fish are low impact because catching them doesn't burn much fossil fuel, the major source of emissions for fisheries.

Ninety percent of the greenhouse gas emissions associated with wild seafood come from fuel use, said Peter Tyedmers, who studies the environmental consequences of food systems at Dalhousie University in Halifax, Nova Scotia.

"If you think about fishing, where does fuel get burned?" he said. "On a fishing boat, it's driving the engine. Some fisheries guzzle more gas than others. It depends how long and how hard the engine works.

Fisheries targeting anchovy, mackerel and similar fish are the most fuel efficient, according to a 2015 study coauthored by Tyedmers. They average less than 80 liters of fuel per ton of catch when fishermen use purse-like nets to surround huge schools of the fish. Because these species swim in dense aggregations, fishermen can locate a swarm, throw a net around the whole thing, and pull up thousands of fish in one trip.

Compare this to crustaceans like Australian Tiger prawns or Norway lobster, which can burn more than 10,000 liters of fuel per ton of catch. That's because it takes a lot of gas to drag a heavy prawn net through the water, as does motoring from one lobster trap to another. Scooping up a whole school of fish at once is much more fuel efficient.

Conservation status matters too, said Nathan Pelletier, an ecological economist and industrial ecologist, specializing in food system sustainability at the University of British Columbia. When populations are healthy, there are more fish in the water, so it takes less time and less fuel to fill a net. Overfishing leaves fewer fish out there, so it takes more time and energy to catch the same amount.

"Abundant fisheries, from a climate change perspective, will be less greenhouse gas intensive," Pelletier said. "All else being equal, the more fish there are, the less energy we will have to invest in chasing them around and catching them."

Farmed mollusks may be another climate-conscious seafood, according to a forthcoming study by ecologist Ray Hilborn, at the University of Washington in Seattle. That's because these shellfish don't need to be fed; they can filter sustenance from the water instead. Animal feed can be a huge consideration when it comes to a farm's carbon footprint.

"From a climate change perspective, what you feed and how much you feed matters a lot," said Tyedmers. "In aquaculture, the big generalization is your greenhouse gas emissions are overwhelmingly driven by your feed inputs."

Farmed fish eat a combination of plant and animal parts, like ground up soy or corn, chicken feathers, animal bones and blood. Each ingredient takes energy to grow or catch, and then more energy to process into pellets or flakes. Farming mollusks sidesteps that issue, because they're filter-feeders, no pellets required.

Hold on though, Pelletier said. The jury is still out on mollusks. They don't need to be fed, but they do take effort to seed, harvest and process for human consumption. Considering the amount of meat on a mussel or oyster, it's a low edible yield for the effort.

Farmed mollusks may look good in theory, but Pelletier says he'd be cautious to endorse them, because "it's mostly shell."

Of course, to reduce carbon footprints as much as possible, the best bet is to eat veggies. On average, eating plants has a smaller footprint than eating animals, said Friederike Ziegler, who studies sustainable seafood at the Research Institutes of Sweden, in Gothenburg. But among animal products, seafoods are some of the best, she said. And among seafoods, little fish are the best of the best.

In Sweden, where Ziegler lives and works, the government recommends eating seafood two to three times per week. Most Swedes eat less than that. Small, schooling fish like herring are famously popular in Scandinavia, but even in Sweden, Ziegler said people could eat more fish.

Not everyone can switch to veggies, for both cultural and nutritional reasons. Wild sustainable seafood is the best option, in many parts of the world. When it comes to changing diets, "we have to think about solutions that are culturally appropriate and feasible within their specific contexts," Pelletier said.

Climate change looms large over the future. To fight it, think like an ocean predator. Dive into the little fish, with big potential for good.

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Eating seafood can reduce your carbon footprint, but some fish are better than others

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Food is expensive. Not just for pocketbooks, but for the planet. Worldwide, more than 25 percent of greenhouse gas emissions come from food production. That's methane belched from cows and nitrous oxide escaping from soils, as well as fossil fuels burned by tractors, fishing boats and rumbling transport vehicles.

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9. how does a increasing consumption of and demand for meat in a human's diet relate to carbon emissions? 

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9. how does a increasing consumption of and demand for meat in a human's diet relate to carbon emissions? 

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more than 25 percent of greenhouse gas emissions come from food production, especially cows.

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Food is expensive. Not just for pocketbooks, but for the planet. Worldwide, more than 25 percent of greenhouse gas emissions come from food production. That's methane belched from cows and nitrous oxide escaping from soils, as well as fossil fuels burned by tractors, fishing boats and rumbling transport vehicles. Some foods cost more than others.

Seafood has a smaller carbon footprint than other animal proteins, on average, because fishing doesn't require farmland or care of livestock. But even among seafoods, fish and shellfish can have varying impacts.

So what's the best choice? Small schooling species, like anchovies and herring, are the most sustainable options, experts say, based on energy use and emissions of their fisheries. There's no free lunch. The question is, what can the planet afford?

Small schooling fish are low impact because catching them doesn't burn much fossil fuel, the major source of emissions for fisheries.

Ninety percent of the greenhouse gas emissions associated with wild seafood come from fuel use, said Peter Tyedmers, who studies the environmental consequences of food systems at Dalhousie University in Halifax, Nova Scotia.

"If you think about fishing, where does fuel get burned?" he said. "On a fishing boat, it's driving the engine. Some fisheries guzzle more gas than others. It depends how long and how hard the engine works.

Fisheries targeting anchovy, mackerel and similar fish are the most fuel efficient, according to a 2015 study coauthored by Tyedmers. They average less than 80 liters of fuel per ton of catch when fishermen use purse-like nets to surround huge schools of the fish. Because these species swim in dense aggregations, fishermen can locate a swarm, throw a net around the whole thing, and pull up thousands of fish in one trip.

Compare this to crustaceans like Australian Tiger prawns or Norway lobster, which can burn more than 10,000 liters of fuel per ton of catch. That's because it takes a lot of gas to drag a heavy prawn net through the water, as does motoring from one lobster trap to another. Scooping up a whole school of fish at once is much more fuel efficient.

Conservation status matters too, said Nathan Pelletier, an ecological economist and industrial ecologist, specializing in food system sustainability at the University of British Columbia. When populations are healthy, there are more fish in the water, so it takes less time and less fuel to fill a net. Overfishing leaves fewer fish out there, so it takes more time and energy to catch the same amount.

"Abundant fisheries, from a climate change perspective, will be less greenhouse gas intensive," Pelletier said. "All else being equal, the more fish there are, the less energy we will have to invest in chasing them around and catching them."

Farmed mollusks may be another climate-conscious seafood, according to a forthcoming study by ecologist Ray Hilborn, at the University of Washington in Seattle. That's because these shellfish don't need to be fed; they can filter sustenance from the water instead. Animal feed can be a huge consideration when it comes to a farm's carbon footprint.

"From a climate change perspective, what you feed and how much you feed matters a lot," said Tyedmers. "In aquaculture, the big generalization is your greenhouse gas emissions are overwhelmingly driven by your feed inputs."

Farmed fish eat a combination of plant and animal parts, like ground up soy or corn, chicken feathers, animal bones and blood. Each ingredient takes energy to grow or catch, and then more energy to process into pellets or flakes. Farming mollusks sidesteps that issue, because they're filter-feeders, no pellets required.

Hold on though, Pelletier said. The jury is still out on mollusks. They don't need to be fed, but they do take effort to seed, harvest and process for human consumption. Considering the amount of meat on a mussel or oyster, it's a low edible yield for the effort.

Farmed mollusks may look good in theory, but Pelletier says he'd be cautious to endorse them, because "it's mostly shell."

Of course, to reduce carbon footprints as much as possible, the best bet is to eat veggies. On average, eating plants has a smaller footprint than eating animals, said Friederike Ziegler, who studies sustainable seafood at the Research Institutes of Sweden, in Gothenburg. But among animal products, seafoods are some of the best, she said. And among seafoods, little fish are the best of the best.

In Sweden, where Ziegler lives and works, the government recommends eating seafood two to three times per week. Most Swedes eat less than that. Small, schooling fish like herring are famously popular in Scandinavia, but even in Sweden, Ziegler said people could eat more fish.

Not everyone can switch to veggies, for both cultural and nutritional reasons. Wild sustainable seafood is the best option, in many parts of the world. When it comes to changing diets, "we have to think about solutions that are culturally appropriate and feasible within their specific contexts," Pelletier said.

Climate change looms large over the future. To fight it, think like an ocean predator. Dive into the little fish, with big potential for good.

# data[].attributes.attachment_link.title
Eating seafood can reduce your carbon footprint, but some fish are better than others

# data[].attributes.attachment_link.description
Food is expensive. Not just for pocketbooks, but for the planet. Worldwide, more than 25 percent of greenhouse gas emissions come from food production. That's methane belched from cows and nitrous oxide escaping from soils, as well as fossil fuels burned by tractors, fishing boats and rumbling transport vehicles.

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8. Does the gasoline that most cars need to operate and function contribute to the Earth's greenhouse effect?

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8. Does the gasoline that most cars need to operate and function contribute to the Earth's greenhouse effect?

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Yes, it does. Greenhouse gases are gases that trap heat in the atmosphere. The largest sources of transportation-related greenhouse gas emissions include passenger cars and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans.

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7. Let's say after college you return to Lisle permanently for the rest of your life. We live in close environmental refugees into our area? Explain.

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7. Let's say after college you return to Lisle permanently for the rest of your life. We live in close environmental refugees into our area? Explain.

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It could be because Lisle is much warmer than Wisconsin or Canada. The temperature difference between summer and winter is terribly big. But it is much better than always cold in the whole year.

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6. What's an environmental refugee? What places will people free from?  Where will they go?

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6. What's an environmental refugee? What places will people free from?  Where will they go?

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Environmental refugees are the people who moves to the place where they can live more comfortable than before.

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5. Are increasing levels of carbon dioxide in the atmosphere safe for human existence?

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5. Are increasing levels of carbon dioxide in the atmosphere safe for human existence?

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No. It makes human sick, breathing difficulty, and so on.

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Carbon Dioxide: Your Environment, Your Health | National Library of Medicine

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Learn where carbon dioxide is found in our environment, how it is used, and the potential human health risks of exposure. Find out how to protect yourself, your family, and your community.

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4. Compare global warming population numbers with rising carbon dioxide levels. Are they related?

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4. Compare global warming population numbers with rising carbon dioxide levels. Are they related?

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Yes they are because carbon dioxide is an important heat-trapping gas.

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Climate Change: Vital Signs of the Planet

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Carbon dioxide (CO ₂) is an important heat-trapping gas, also known as a greenhouse gas, that comes from the extraction and burning of fossil fuels (such as coal, oil, and natural gas), from wildfires, and natural processes like volcanic eruptions. The first graph shows atmospheric CO ₂ levels measured by NOAA at Mauna Loa Observatory, Hawaii, since 1958. The second graph shows CO ₂ levels during Earth's last three glacial cycles, as captured by air bubbles trapped in ice sheets and glaciers.

Since the onset of industrial times in the 18th century, human activities have raised atmospheric CO ₂ by 50% - meaning the amount of CO ₂ is now 150% of its value in 1750. This human-induced rise is greater than the natural increase observed at the end of the last ice age 20,000 years ago.

The animated map shows how the historical changes in global carbon dioxide over time. Note the colors change as the amount of CO ₂ rises from 365 parts per million (ppm) in 2002 to over 420 ppm currently. It's important to understand that "parts per million" refers to the number of carbon dioxide molecules per million molecules of dry air. These measurements are from the mid-troposphere, the layer of Earth's atmosphere that is 8 to 12 kilometers (about 5 to 7 miles) above the ground. This data provides insights into the significant rise in atmospheric CO2 concentrations, highlighting the impact of human activities on Earth's climate.

CO₂ Through the Seasons

A closer look at the carbon dioxide measurements at Mauna Loa shows a series of wiggles in the data. Although total CO ₂ is increasing each year, there is also a short-term cycle visible within the larger trend.

This annual rise and fall of CO ₂ levels is caused by seasonal cycles in photosynthesis on a massive scale. In Northern Hemisphere spring, plants come to life and draw in CO ₂ to fuel their growth. This begins the process of lowering the amount of CO ₂ in the atmosphere. In northern autumn, plant growth stops or slows down, and the whole process reverses itself. Much of the plant matter decomposes, releasing CO ₂ back to the atmosphere.

A similar but less intense pattern repeats in the Southern Hemisphere in opposite seasons. Spring growth starts in September and winter decomposition begins in March, so CO ₂ records in the Southern Hemisphere show the opposite pattern of that seen in Mauna Loa. However, because there is a lot more land and vegetation in the Northern Hemisphere than the southern, the global seasonal cycle more closely aligns with the northern pattern.

See the cycle in action in the visualization Watching Earth Breathe: The Seasonal Vegetation Cycle and Atmospheric Carbon Dioxide.

This boom-and-bust cycle of plant growth gives the graph of CO ₂ a sawtooth pattern of ups and downs from year to year. At a larger scale, the upward climb of the trend line over the decades is caused by CO ₂ emissions, primarily from burning fossil fuels. Thus, the data illustrate both natural factors and human additions of CO ₂.

Learn more:

NASA's Climate Kids: Why is Carbon Important?

Missions That Observe CO₂
Atmospheric Infrared Sounder (AIRS) Orbiting Carbon Observatory (OCO-2) Orbiting Carbon Observatory (OCO-3)

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Carbon Dioxide Concentration | NASA Global Climate Change

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Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

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1. Why do people believe global warming is occuring on Earth?

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1. Why do people believe global warming is occuring on Earth?

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Because the world temperature, the carbon dioxide, sea level is increasing.

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Climate Change: Vital Signs of the Planet

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Home - Climate Change: Vital Signs of the Planet

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Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

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2. Why are some people skeptical of global warming?

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2. Why are some people skeptical of global warming?

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Because some scientists say that the global warming was happened in the past. Also they say the climate change is not concerned with the global warming.

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Translations of Global Warming Skeptic Arguments

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

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3. Where is the fastest warming of Earth's atmosphere occurring?

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3. Where is the fastest warming of Earth's atmosphere occurring?

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Arctic is. The temperature rise occurs twice as fast as all the other area in the world. Also as the temperature rises, the ice in the Arctic is melting.

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vol.5 世界で一番早く、そして深刻な影響が出ている北極 - JCCCA 全国地球温暖化防止活動推進センター

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全国地球温暖化防止活動推進センター(JCCCA)は地球温暖化防止活動に役立つ情報の収集発信の場です