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List five commonly used devices that waste large amounts of energy.

-light switch -incandescent lightbulbs -internal combustion engine that powers most cars and trucks -A coal-burning power plant - industrial electric motors

About how much of the commercial energy used in the United States is unnecessarily wasted?

43% The percentage of all commercial energy used in the United States that is unnecessarily wasted

What are two ways in which countries can cooperate to deal with climate change?

On the global level, countries have been working together to slow climate change. In December 1997, more than 2,200 delegates from 161 nations met in Kyoto, Japan, to negotiate an international agreement to slow atmospheric warming. The first phase of the resulting Kyoto Protocol went into effect in February of 2005. As of 2012, 191 of the world's 194 countries (not including the United States) had ratified the agreement. This agreement requires the 39 participating more-developed countries to cut, by 2012, their emissions of CO2, CH4, and N2O to an average of at least 5.2% below their 1990 levels. By 2011, only a few of these countries had met this modest goal. Less-developed countries, including China and India, both of which produce a great deal of CO2 by burning coal, were excluded from this requirement in its first phase, because such reductions would curb their economic growth. In 2005, the participating countries began negotiating a second phase, which was supposed to go into effect after 2012, but the negotiations failed in 2011. ----------------- On the international level, it will become increasingly important for more-developed countries to share their technological and engineering knowledge with less-developed countries through technology transfer programs. Some of the more-developed countries could help poorer countries avoid the mistakes that richer countries have made by sharing what they have learned about energy efficiency, low-carbon renewable energy technologies, pollution prevention and cleanup, and sustainable forestry and agriculture.

List three pieces of evidence that IPCC scientists have used to support their conclusions.

The 25 warmest years on record have occurred since 1980, and the 10 warmest years have occurred since 1998. In some parts of the world, glaciers have been melting and floating sea ice has been shrinking for several decades. Rainfall patterns are changing. Extreme and prolonged drought is getting worse in various parts of the world due to rising temperatures and too little rainfall. Other areas are experiencing extreme and more frequent flooding from too much rainfall

How are warmer ocean waters affecting coral reefs? What is ocean acidification and what are its likely harmful effects?

Warmer tropical waters in several areas are already leading to the bleaching and destruction of temperature-sensitive coral reefs that serve as centers of marine biodiversity Our massive inputs of CO2, while they have led to the warming of the atmosphere and ocean waters, are also increasing the acidity of the world's ocean water in a process called ocean acidification, which could lead to further disruption of some ocean ecosystems and the human economies that depend on them. Jane Lubchenco, marine ecologist and head of the National Oceanic and Atmospheric Administration (NOAA), calls ocean acidification the "equally evil twin" of atmospheric warming. When the acidity of ocean water rises, the level of carbonate ions (CO32−) in the water decreases. These ions are vital to marine organisms that build shells and to those that build coral reefs. Thus, more acidic ocean water not only dissolves or weakens shells and structures such as reefs, but it makes it harder for marine organisms to replace them.

List four examples of how people can prepare for moderate climate change.

Ways to do so pic

List three carbon sequestration approaches to geoengineering and summarize the drawbacks of each.

1. One carbon sequestration approach involves efforts to remove CO2 from the atmosphere and store it in soils and plant tissues. This could be done by preserving and restoring natural forests and by planting billions of trees in plantations throughout the world. 2. Another carbon sequestration scheme would involve dropping massive amounts of iron powder into ocean waters to spur blooms of phytoplankton, tiny aquatic organisms that use iron as a nutrient. These organisms remove CO2 from the atmosphere as they grow. When they die, they sink to the ocean floor, carrying the carbon with them. 3. Another sequestration approach, called carbon capture and storage (CCS), involves removing CO2 from smokestack emissions and storing it in soils, in caverns underground (where oil and natural gas or coal have been removed), in deep ocean waters, or beneath the ocean floor.

Why do some experts consider a carbon tax to be a good idea?

A second way for governments to reduce CO2 emissions is to levy a carbon tax on each unit of carbon emitted by a human activity or on each unit of any fossil fuel that is burned. This is being tried in some European countries. Climatologist James Hansen and economists Jeffrey Sachs and William Nordhaus argue that using taxes to put a price on carbon emissions is the best and quickest way to reduce such emissions and to promote a shift to relying more on energy efficiency and low-carbon renewable energy sources. The problem is that most elected officials and citizens generally oppose increasing taxes on anything, and fossil fuel and utility companies in the United States have successfully opposed carbon taxes for more than three decades. However, there might be enough political support for such taxation if taxes on income and wealth were to be reduced to offset the new taxes.

How can government subsidies and tax breaks be shifted to reduce energy waste and greenhouse gas emissions?

A third approach is for governments to phase out subsidies and tax breaks for fossil fuels and nuclear power, and phase in subsidies and tax breaks for energy-efficiency technologies and low-carbon renewable energy sources. Such a subsidy shift could be phased in over one or two decades and would promote jobs and innovation in energy efficiency and low-carbon energy industries.

What will be the major harmful effects of rising sea levels caused by atmospheric warming?

According to a 2008 U.S. Geological Survey report, the world's average sea level is most likely to rise 3-6.5 feet during this century and to keep rising for centuries. This is an example of how the 2007 IPCC report may have underestimated the effects of atmospheric warming. The rise in sea level is very likely to be even greater if Greenland's ice sheet continues to melt at current or higher rates. Even if the world were to make drastic reductions in greenhouse gas emissions starting now, scientists project that the world's average sea level is likely to rise at least 3 feet by 2100, simply because of the built-in effects of the current atmospheric warming. According to the IPCC, this projected change could threaten at least one-third of the world's coastal ecosystems, especially coral reefs that contain much of the world's aquatic biodiversity and coastal wetlands that produce much of the world's seafood and rice. Even this minimal rise will also likely disrupt many coastal fisheries. Such a rise in sea level would flood several low-lying island nations as well as many barrier islands and coastal areas. In doing so, it would contaminate freshwater aquifers lying near these coastlines. Figure 13.23 shows areas of the state of Florida that would be flooded with an average sea level rise of 3 feet. Other low-lying coastal areas and cities throughout the world would also be flooded by this projected rise in sea level.

Why is coal so widely used, according to some economists?

According to many economists, one reason coal is so widely used despite these problems is that the numerous harmful environmental effects of using coal are not included in the market price of coal-fired electricity. As a result, consumers are unaware of these harmful effects. Economists say that this is unlikely to change unless coal is taxed heavily for each unit of energy produced or for each unit of CO2 emitted into the atmosphere.

What are two general strategies for dealing with climate change?

According to most climate scientists, our best way to avoid climate disruption and its most serious, long-lasting harmful effects is to sharply reduce greenhouse gas emissions as quickly as possible. By doing so we would be following the adage: "When you find you have dug yourself into a hole, the first thing to do is to stop digging." With this strategy, the urgent goal would be to keep CO2 levels and atmospheric temperatures from exceeding the levels shown in the picture. A second option would be to accept some degree of warming as unavoidable and to find ways to soften the harmful effects of modest climate change.

What two human activities are primarily responsible for rising levels of CO2 in the atmosphere and how do they interfere with the carbon cycle?

According to the IPCC and other researchers, two major human activities—the burning of fossil fuels and the clearing of vast tracts of forestland, especially in tropical areas—are largely responsible for the rise in atmospheric levels of soot and CO2 and, thus, for the observed atmospheric warming since 1980 These activities have interfered with the carbon cycle in two ways. First, we have emitted huge amounts of CO2 into the atmosphere by burning fossil fuels and by burning forests to make way for plantations, cattle grazing, and human settlements. Studies have shown that these inputs of CO2 can remain in the atmosphere for at least 100 years. The second major way in which we have interfered with the carbon cycle also has to do with the clearing of forests, especially tropical forests. Because we have cleared massive amounts of trees and other vegetation, the carbon cycle now removes far less CO2 than it would if the forests had not been cleared.

How might climate change affect food production?

According to the IPCC, moderate climate change could improve farming in parts of Canada, Russia, and Ukraine, but food production there will be limited by relatively poor soils. If warming goes beyond moderate levels, agriculture in most areas of the world is very likely to decline because of drier soils, scorching temperatures, more severe and more frequent extreme weather events, and rising populations of many crop-eating insects and fast-growing weeds. This will likely lead to wide swings in annual food production yields and prices.

How does methane compare with CO2 as a greenhouse gas?

Another greenhouse gas that is causing great concern among scientists is methane, which is 23 times more effective per molecule at holding heat in the atmosphere than is CO2. However, it typically remains in the atmosphere for 12 years compared to at least 100 years for carbon dioxide. Methane is emitted in huge quantities by cattle all around the world, as they digest their food, and by leaks from natural gas wells and pipelines and facilities that use natural gas, which is mostly methane. It also comes naturally from bodies of water such as wetlands where large amounts of vegetation are decaying.

How is soot produced and what role does it play in atmospheric warming?

Another major contributor to atmospheric warming, second only to carbon dioxide, is dark-colored soot particles (known as black carbon), which absorb heat and release it into the atmosphere. While soot particles remain in the atmosphere for only a few weeks, compared to 100 years or more for CO2 molecules, soot is playing a major role in atmospheric warming. Soot is produced when a carbon-containing fuel is burned incompletely and emits black smoke containing tiny particles of carbon into the air. The main sources of soot are inefficient coal-burning power and industrial plants without up-to-date air pollution controls, inefficient stoves and open fires used by billions of people for heating and cooking, and millions of motor vehicles, locomotives, and ships that burn diesel fuel inefficiently. Another source is the smoke from forest fires, many of which are deliberately set to clear land, especially in tropical regions.

Define energy conservation and energy efficiency.

Another name for reducing the unnecessary use and waste of energy is energy conservation. It involves doing things such as turning the thermostat setting down at night (or programming a thermostat to do this automatically and to raise the setting in the morning) and adding insulation and plugging leaks in houses. The best way to cut energy use and waste is to improve energy efficiency: the measure of how much work we get from each unit of energy we use. Most of our energy waste and a good deal of our climate-changing CO2 emissions are due to our use of inefficient lighting, appliances, and other devices

What is carbon capture and storage (CCS)? What are three major problems associated with CCS?

Another sequestration approach, called carbon capture and storage (CCS), involves removing CO2 from smokestack emissions and storing it in soils, in caverns underground (where oil and natural gas or coal have been removed), in deep ocean waters, or beneath the ocean floor. The extracted CO2 might also be chemically converted to highly stable magnesium carbonate (MgCO3) rock. First, the stored CO2 would have to remain sealed from the atmosphere forever, which many scientists doubt can be done. Large-scale leaks and prolonged small-scale leaks of stored CO2 could quickly increase atmospheric warming and climate change. Rapid leaks could also suffocate and kill large numbers of people if the leaking CO2 were to displace oxygen. This happened in 1986 when a sudden release of a large volume of CO2 from a lake in Cameroon, Africa, killed 1,700 people living within 15 miles of the lake. Second, a large amount of fossil fuels such as gasoline and diesel fuel would be burned in the process of carrying out CCS. This would involve high CO2 emissions, and it would raise the cost of using coal, thereby raising the price of coal-fired electricity, unless CCS were to be subsidized by taxpayers, which would also result in higher costs to consumers. Because of this, the IPCC has estimated that even with a government-supported crash program, maximum use of CCS would reduce CO2 emissions by less than 20% by 2050, and at a great cost. The third problem with CCS is that it would seem to make coal a more acceptable fuel, even with all of its other harmful environmental and health effects. This would justify burning more of it, and if CCS does not work, the total effect on climate change could be much worse than it already is. The fact that CCS could make coal more acceptable to many explains why the coal industry and coal-burning utility companies heavily favor the CCS technological fix, especially if they can get government subsidies to help pay for it.

What is the role of carbon dioxide in changes to the global average temperature of the atmosphere?

Carbon dioxide (CO2) plays an important role in regulating the average temperature of the earth's atmosphere, which together with precipitation, helps to determine the earth's overall climate. (((((((((( When the carbon cycle removes CO2 from the atmosphere faster than it is added, all other things being equal, the average global atmospheric temperature drops because there is less CO2 available to absorb energy and release heat. )))))) Similarly, when CO2 is added to the atmosphere faster than the carbon cycle can remove it, the earth's atmospheric temperature rises. Carbon dioxide levels have long-term consequences because CO2 molecules, on average, remain in the atmosphere for at least 100 years. In 1894, Swedish chemist Svante Arrhenius (1859-1927) hypothesized that certain human activities, especially the greatly increased burning of coal during the 1800s, were adding CO2 to the atmosphere faster than the carbon cycle could remove it, and that if they were kept up, these activities would lead to a warmer atmosphere. Since then, countless measurements and experiments have supported Arrhenius' hypothesis Carbon dioxide plays the key role in atmospheric warming, but there are other factors, including changes in the output of energy from the sun. Another important factor is the concentrations of other greenhouse gases such as methane (CH4) and nitrous oxide (N2O), both of which have also been rising and are much more potent as greenhouse gases than CO2.

Define climate change. Why should you care about climate change?

Climate change—long-term changes in the earth's average temperature, precipitation, and other environmental factors. According to these widely accepted scientific conclusions, climate change is taking place now and will very likely accelerate as atmospheric temperatures rise. If this occurs, it will change life as we know it by causing some areas of the world to get too little water and causing other areas to get too much. Extreme weather events such as severe droughts, heat waves, storms, and floods are likely to increase in frequency and intensity in various parts of the world. There will also likely be changes in where food can be grown and where people and many of the world's plants and animals can live and thrive. For example, production of corn and other crops may drop in some areas such as the U.S. Midwest because of a hotter and drier climate. Polar bears, which survive by hunting seals on floating Arctic ice, may become extinct as warmer temperatures continue to melt that ice. Projected climate change has the potential to cause considerable harm to our economies and our societies, as well as to hundreds of generations of humans and many other species. This is why most climate scientists see it as one of the most important and urgent environmental threats that humanity faces—and something about which we ought to care deeply.

Why is it that reducing use of coal is one of the best ways to reduce emissions of climate-changing CO2?

Coal-burning power plants provide 44% of the electricity used in the United States and 80% of that used in China. When it is burned, coal emits more CO2 and more air pollutants per unit of energy than any other fossil fuel. Thus, reducing coal use is one of the best ways to reduce emissions of CO2 as well as a variety of harmful air pollutants that sicken and kill large numbers of people.

What effect is the melting of mountain glaciers around the world having on the oceans? What is the other way in which atmospheric warming is raising sea levels?

However, as more ice melts from land-based glaciers, water is added to the oceans, causing sea levels to rise. Also, as ocean waters warm up, they expand into a larger volume, which also contributes to the rise in sea levels.

Explain why nuclear power is not carbon-free.

However, many proponents of this idea do not realize that, when we include all phases of nuclear power production—in what is called the nuclear fuel cycle—nuclear power is far from carbon-free. While operating, the plants produce no CO2, but large amounts of CO2 are generated in mining the fuel, building the plants, and storing the growing amounts of highly radioactive wastes. Even though the nuclear fuel cycle produces less CO2 per unit of electricity than coal-fired power plants produce, use of nuclear power is extremely costly and can lead to accidents that emit long-lived radioactive material into the air and water, as happened in Japan in 2011. Guaranteeing public safety in and around nuclear power plants takes a great deal of time, energy, and money. Use of the nuclear fuel cycle produces dangerous radioactive wastes that must be safely stored for thousands of years, and it spreads the knowledge and technology that can be used to develop nuclear weapons.

What is the IPCC?

In the early 1980s, climate scientists became increasingly concerned about how rising average annual atmospheric temperatures and CO2 levels might affect the global climate. In 1988, in response to these concerns, the United Nations and the World Meteorological Organization established: the Intergovernmental Panel on Climate Change (IPCC) to study historical temperature and climate changes, and to project future changes in the earth's climate.

How could governments regulate CO2 emissions and why is such regulation difficult to implement?

In the first approach, governments would classify CO2 as an air pollutant and regulate its emissions just as they regulate other air pollutants. However, regulation of CO2 as a pollutant would be an economic burden for oil, coal, and natural gas companies as well as coal-burning utility and manufacturing companies because there is no way to burn fossil fuels without adding CO2 to the atmosphere. Thus, it is not surprising that for more than 30 years, these companies have successfully used their political and economic power to oppose any regulation of CO2 emissions and to cast doubt on whether human-influenced atmospheric warming is real. However, proponents of regulation, including the CEOs of many major corporations, warn that unless CO2 is regulated as a pollutant, there is little chance of significantly reducing emissions of this climate-changing gas.

What is the greenhouse effect and why is it important to life on the earth? What are greenhouse gases? List four naturally occurring greenhouse gases.

Life on planet Earth depends on the greenhouse effect—the process by which the lower atmosphere temporarily stores some of the energy received from the sun as heat. Without the greenhouse effect, the earth would be extremely cold and most likely lifeless. This warming occurs primarily because of the presence in the lower atmosphere of greenhouse gases—gases that have the effect of temporarily holding some of the sun's energy as heat. As some of the sun's energy is reflected from the planet's surface back toward space, greenhouse gases interact with this energy and release heat into the earth's lower atmosphere. Four naturally occurring and abundant greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).

What are the major concerns about relying on geoengineering schemes as a substitute for reducing our greenhouse gas emissions?

Many scientists argue that implementing either of the major types of geoengineering fixes on a global scale could be dangerous and uncertain because of our limited understanding about how the earth's climate and other life-sustaining systems work. The big fear of many climate scientists is that implementing such fixes might cause us to give up on efforts to reduce emissions of CO2 and other climate-changing gases. If these systems then fail to slow climate change, we will have accelerated climate disruption and all of its long-term, severely harmful effects.

List the pros and cons of a carbon tax.

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Generally, what is the global dimming approach to geoengineering? Give two examples of such schemes and list the problems associated with each.

Reduce the amount of sunlight reaching the earth's surface in order to cool the atmosphere—known as global dimming technological fixes. One such global dimming scheme calls for using airplanes and balloons to inject sulfate particles into the upper atmosphere. It is estimated that these particles would reflect about 2% of the incoming sunlight back into space, which would prevent some of the warming of the lower atmosphere. Another scheme calls for placing hundreds of thousands of reflective disks or mirrors into orbit above the earth to reflect some of the incoming solar energy. Critics point out that burning enough rocket fuel to launch and maintain such a massive system would dump enough CO2 into the lower atmosphere to add to the warming and to partially offset any benefit gained by the project.

How could we lower carbon emissions within the transportation sector?

Scientists and engineers are developing transportation options that rely more on renewable energy resources. For example, plug-in hybrid electric vehicles and electric cars and buses could some day replace most of the gasoline-and diesel-powered vehicles now in use. These energy-efficient vehicles would run mostly on electricity, and their batteries could be recharged by wind-generated electricity or by solar power or other renewable energy sources that involve low carbon emissions.

What is the current level of CO2 in the atmosphere in parts per million? What is the level that some scientists think we should not exceed?

Scientists measure CO2 levels in the atmosphere in parts per million, or ppm—one part CO2 for every million parts air. current CO2 level of 393 ppm we need to prevent CO2 levels from rising above 450 ppm

What are the IPCC projections about higher rates of extinction due to climate change?

Scientists report that some extinctions related to climate change are happening now on every continent. According to the IPCC: nearly one of every three land-based plant and animal species could disappear if the average global temperature changes by 2.7-4.5 F°. This number could grow to 7 of every 10 species if the temperature change exceeds 6.3 F°. For those species that can adapt quickly enough to climate change, atmospheric warming could expand their ranges and populations. But some of these organisms—such as weeds, fire ants, disease-carrying organisms, and beetles that kill trees—will likely threaten many other species as they expand. According to some biologists, the net effect will likely be a loss of biodiversity, with rare and specialized species declining and more adaptable generalist species thriving.

What are the major conclusions of the 2007 IPCC report and the 2010 report by the U.S. National Academy of Sciences?

Since 1980, the lower atmosphere on average has warmed at an accelerating rate by about 1.4 F° and CO2 levels have been increasing since 1958. Computer models and other data indicate that most of the temperature increase since 1980 is due to human activities, especially the burning of fossil fuels, which has raised atmospheric CO2 levels, and the rapid clearing of forests and other vegetation that, if left in place, would take up much of the excess CO2 from the atmosphere. The climate is beginning to change, and if human activities that promote such change continue at their current or higher rates, we will likely experience further rapid atmospheric warming and long-term climate disruption during this century. ------------ In 2010, the U.S. National Academy of Sciences—the nation's leading scientific body—said that: "a strong and credible body of evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems."

Summarize the findings of computer modeling that compared natural factors with human factors in projecting global average temperature changes.

Some climate scientists have used the latest climate models to project how natural factors by themselves would have affected global average atmospheric temperatures between 1901 and 1997, and they compared those projections with the actual observed changes during that time. They also did the same analysis using a combination of natural and human factors. ----They found that when only natural factors were considered, the projections did not match the observed temperature changes. ------However, when human factors were included with natural factors, the projections did match the observed atmospheric temperature changes fairly closely The usefulness of a climate model depends on the assumptions used to develop the mathematical equations that form the model. It also depends on the environmental factors included in the model, the quality of the data fed into the models, and the statistical methods used to process the data and to arrive at projections. These computer climate models, even though they have some limitations, are the best tools we have for projecting future atmospheric temperature changes as well as other aspects of climate change. Climate scientists are always looking for ways to improve the models.

What is a cap-and-trade system? Summarize its pros and cons.

Some experts argue for using the economics of the market system to help us slow projected climate change, in addition to, or in place of, the three government actions discussed above. One such approach would be to use a cap-and-trade system. In such a program, a government would provide emitters of greenhouse gases with annual permits, which would allow each of them to emit a certain amount of CO2 or some other greenhouse gas. A permit owner emitting less CO2 than its permit allowed would have a surplus of carbon credits. It could use such credits to offset higher emissions from other facilities that it owned or keep them for future use or sell them to other parties. Experts caution that a cap-and-trade system would not bring about a significant reduction in CO2 emissions unless the cap was gradually reduced over time to keep spurring innovation in dealing with the problem.

Explain why disagreement among scientists is to be expected. What are two important factors to keep in mind in evaluating opposing arguments?

Some scientists disagree with the IPCC conclusions. This is to be expected because scientific knowledge advances through vigorous debate and constant pressure to improve evidence and models. In fact, the criticisms of those who disagree with some of the more detailed findings of the IPCC have led to better climate data and climate models that further support the IPCC findings. 1. First, in light of the measurements and climate models, a large majority of the world's climatologists and other climate experts generally agree with the IPCC conclusions. In fact, because the IPCC findings involve inputs from so many people, and because scientists tend to be conservative in making conclusions, they may be underestimating the rate and effects of climate change. 2. Second, most of the scientists, economists, politicians, and talk-show hosts who disagree with the IPCC conclusions are not experts in the extremely complex field of climate science. Many of their statements and conclusions are about weather, not climate, and some widely repeated statements are issued by individuals and groups that have a financial interest in our continuing to use fossil fuels at current or higher rates.

Why is corn-based ethanol not a low-carbon option?

The amount of energy that motorists get from ethanol fuel made from corn is little more than the amount of energy it takes to produce this fuel. The latter includes energy used to fuel tractors and to make fertilizers, most of which comes from fossil fuels, which release CO2 into the atmosphere when burned.

Summarize the likely effects of rapid climate change during this century.

The likely effects of climate disruption are numerous. - Some areas will get hotter and some will get colder; some will get drier and some will get wetter. Some forests are likely to die back and their ecosystems will change. -More frequent and far-reaching forest fires are likely to rage in areas that become drier and this could lead to an era of megafires. They will make matters worse by adding more climate-changing CO2 and soot to the atmosphere and by reducing vegetation that removes CO2 from the atmosphere. Experts warn that such effects could be irreversible for hundreds to thousands of years. This would make the planet a much less hospitable place for many future generations of humans and other species. We look at the effects of climate disruption in more detail later in this module.

What is the main problem for many threatened species resulting from climate change?

The main problem for many threatened species is that changes in climate can destroy or fragment their habitat, as is the case with polar bears in the Arctic that depend on sea ice that is melting at increasing rates. Plants and animals in areas undergoing such environmental changes must adapt to these changes, move to other areas, or go extinct. Many of the earth's plants and animals do not need satellite surveys, thermometers, or climate models to sense that temperatures are rising and that their habitats are disappearing. Studies show that during the past 40 years, many of the world's animals (especially certain species of birds, bees, ants, and fishes) have been expanding their ranges north or south out of tropical regions toward the earth's poles. Some plants and animals are moving up mountain slopes to find cooler conditions as their habitats change in warmer, lower altitudes.

List two ways in which scientists get information on past changes in atmospheric temperature and carbon dioxide levels.

They have studied tree rings that reflect the annual growth of trees, and they have examined ancient fossils, marine sediments, and tiny bubbles of ancient air found in ice cores drilled from glaciers. Scientists also use these and other techniques to estimate precipitation levels over long periods of time, and they collect data to estimate and measure changes in average sea levels and ocean temperatures. 1. Since 1880, atmospheric temperatures have been measured at various locations and altitudes around the world. Since 1982, satellites with infrared sensors have also been measuring the temperature of various parts of the earth's surface on a daily basis. 2. One of the reasons why scientists have studied air bubbles trapped in ice cores is to get historical data on CO2 levels in the atmosphere before direct measurements were ever made

Why is this difficult to implement?

This is not likely to happen, however, unless citizens pressure elected officials enough to overcome the political and economic power of the fossil fuel, utility, and nuclear industries that oppose such a shift.

How has the earth's average atmospheric temperature changed over the last 900,000 years and during the 10,000 to 12,000 years since the last ice age ended?

Throughout earth's long history, its average atmospheric temperature, precipitation levels, and other factors that determine its climates have changed many times in many ways. Factors affecting the planet's changing climate have included multiple large volcanic eruptions, changes in the sun's output of energy, the gradual growth and shrinkage of oceans as land-based ice melted or expanded, and devastating impacts by large meteors and asteroids. Thus, over the past 900,000 years, the earth's atmosphere has experienced prolonged periods of both cooling (which led to ice ages) and warming (which melted much of the ice) ------------------- As a result, for roughly the past 10,000 to 12,000 years, we and millions of other species have lived with a fairly warm and stable climate over most of the earth's surface. This has allowed the human population to flourish, to develop agriculture, and to build societies and cities. It also helped to support dramatic and accelerating human population growth.

How do climate experts use models of the earth's climate to estimate past atmospheric temperatures and to project future temperatures?

To study the effects of rising levels of greenhouse gases and other factors on average global temperatures, climate scientists use mathematical models to simulate the earth's climate system. They run these very complex models on supercomputers, using data on solar energy, cloud cover, the earth's landmasses and oceans, ocean currents, concentrations of greenhouse gases and major air pollutants, and other environmental factors. They then compare the results to past temperature changes and project future changes in the earth's average atmospheric temperatures. It is important to note that, with these models, scientists do not attempt to predict what will actually happen. Rather, they use the models to make projections, or statements about what is likely to happen to the global average atmospheric temperature during a certain period of time, given all the data and trends that they have analyzed.

Define and compare weather and climate. What are two major factors that help to determine climate?

Weather consists of short-term changes in atmospheric variables such as temperature and precipitation in a given area over a period of hours or days. Weather can change quickly and tends to fluctuate from day to day and from year to year between warmer and cooler and between wetter and drier periods. Climate, by contrast, is determined by the average weather conditions, especially temperature and precipitation, in a particular area over periods ranging from at least three decades to thousands of years. First, find data for the average annual temperature Second, plot these average annual temperatures on a graph and note whether they have generally risen, dropped, or stayed about the same during the entire time plotted.

What is drought and how will climate change affect it globally?

drought an extended period of dry weather resulting from a combination of higher-than-normal temperatures and lower-than-normal precipitation. One of the major harmful effects of drought is that it dries up soil, which can lead to crop losses In recent decades, drought has affected a growing area of the earth's land and, in some areas, is becoming more severe and long-lasting.

What are three extreme weather events that might increase in frequency with more atmospheric warming?

intense and longer heat waves damaging storms extreme cold and blizzard conditions

Give an example of what is being done to reduce greenhouse gas emissions by national governments, state governments, local governments, colleges and universities, and private companies.

national governments, Some nations are taking the lead on the world stage. Costa Rica plans to be the first country to become carbon neutral by using renewable, low-carbon energy sources in order to cut its net carbon emissions to zero by 2030. Norway aims to become carbon neutral by 2050, primarily by increasing its reliance on its abundant hydropower and wind power. ---------------- state governments, In the United States, by 2012, some 32 states had adopted climate change strategies. California plans to get 33% of its electricity from low-carbon renewable energy sources by 2030. -------------------- local governments, Local governments in more than 650 cities around the world (including more than 450 U.S. cities) have established programs to reduce their greenhouse gas emissions. --------------------- colleges and universities, and A growing number of colleges and universities have also taken action. Oberlin College in Ohio plans to reduce its CO2 emissions to zero by 2020 by buying or producing low-carbon renewable energy. In the neighboring state of Pennsylvania, 25 colleges have joined to purchase wind power and other forms of low-carbon renewable energy. Other schools such as Northland College in Wisconsin have invested in energy efficiency and renewable energy in their campus buildings. Northland's Environmental Living and Learning Center is a residence hall and meeting space designed to reduce CO2 emissions by reducing energy waste and relying on low-carbon renewable energy. ------------------ private companies. A growing number of major global companies, including Alcoa, DuPont, IBM, Toyota, and General Electric, have set goals for significantly reducing their greenhouse gas emissions. Between 1990 and 2006, DuPont slashed its energy usage and cut its greenhouse gas emissions by 72% and saved $3 billion, while the company increased its business by almost a third. Since then, the company has further reduced its emissions.

Define permafrost, and describe the possible effects of the melting of permafrost in Arctic tundra soils on atmospheric warming and climate change.

permafrost Perennially frozen layer of the soil that forms when the water in it freezes and remains frozen for long periods of time; found in Arctic tundra Because polar regions are warming much faster than other parts of the planet, some of this permafrost is beginning to melt and to release some of the methane and CO2 that have been stored in it for thousands of years. Some scientists refer to these permafrost deposits as climate-change time bombs, which could eventually release amounts of methane and CO2 that would be many times the total amounts now in the atmosphere, resulting in rapid and catastrophic atmospheric warming and climate change

Describe the trends and likely long-term effects of the melting of floating sea ice in the Arctic, land-based glaciers in Greenland, and many of the world's mountain glaciers.

sea ice This will also sharply reduce the Arctic's polar bear population because polar bears depend on the ice for hunting seals—their main food supply. Other animals, such as some species of seals, also depend on this ice for finding their food. This loss of Arctic sea ice could also affect weather and climate in other areas of the globe, because this ice plays a large role in how moisture is picked up and distributed through the atmosphere. In 2010, NOAA researcher James Overland projected that shrinking areas of Arctic sea ice would likely lead to less rainfall and snowfall in the already dry American West and more precipitation, flooding, and colder, snowier winters in western and southern Europe, eastern Asia, and eastern North America. --------- land-based glaciers in Greenland The ice sheet that covers about 80% of Greenland—the world's largest island—has been melting around the edges during the summer at a slow but increasing rate. Complete melting of Greenland's land-based glaciers would add enough water to the oceans to raise the global sea level by as much as 23 feet. This is highly unlikely, but continued partial summer melting of Greenland's ice could raise the global average sea level by several feet. mountain glaciers If most of the world's mountain glaciers shrink at similar rates in the future, as is projected, hundreds of millions of people who rely on glacial meltwater for annual irrigation and hydropower could face severe water, power, and food shortages.

What are three threats to human health that will likely be worsened by climate change?

there will be fewer deaths due to extreme cold weather in a warmer world, but the number of deaths and illnesses due to more frequent, intense, and persistent heat waves in some areas is likely to rise. Already, in 2010, an intense heat wave and fires from dry conditions in Russia claimed 56,000 lives, and 19 nations set all-time high-temperature records. Climate change might also lead to a rise in the incidence of infectious diseases. Warmer temperatures and higher levels of CO2 are very likely to favor rapidly multiplying insects, microbes, toxic molds, and fungi that can transmit such diseases. Microbes that cause tropical infectious diseases such as dengue fever, yellow fever, and malaria are likely to spread from tropical to temperate areas. increasing hunger and malnutrition due to declines in food production in some areas of the world. One area that is projected to be hardest hit by climate change is sub-Saharan Africa where crop losses due to drought are already high and where hunger and malnutrition are now major problems.

What are earth's three major climate zones? Explain how these zones were created.

tropical (warm temperatures), temperate (moderate temperatures), polar (cold temperatures) Three climate zones—tropical, temperate, and polar—are created by uneven solar heating of the planet, the rotation of the earth on its axis, and the resulting prevailing winds and ocean currents that distribute heat and moisture unevenly around the globe. ------------------------ These zones exist because heat and moisture are distributed unevenly around the planet. The equator receives the largest input of solar energy. The intensely heated air at the equator expands, rises, and moves north or south toward one of the earth's poles. The earth's rotation then deflects the movement of air over different parts of the planet, creating prevailing winds that blow almost continually. Note in Figure 13.3 that these winds are either westerly (blowing primarily from the west) or easterly (blowing primarily from the east), depending on how far north or south we go from the equator. The easterly winds are also referred to as the northeast trade winds and the southeast trade winds. Prevailing winds drive the massive movements of ocean water known as ocean currents, which, like the prevailing winds, flow in fairly predictable patterns. Together, these winds and currents help to distribute heat and moisture in the atmosphere to different parts of the planet. In this way, they play a major role in determining various regional climates and climate zones.