* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Are You suprised
Soon and Baliunas controversy wikipedia , lookup
ExxonMobil climate change controversy wikipedia , lookup
German Climate Action Plan 2050 wikipedia , lookup
Economics of climate change mitigation wikipedia , lookup
Climate change denial wikipedia , lookup
Climate change adaptation wikipedia , lookup
Climate sensitivity wikipedia , lookup
Climate change mitigation wikipedia , lookup
2009 United Nations Climate Change Conference wikipedia , lookup
Low-carbon economy wikipedia , lookup
Climatic Research Unit documents wikipedia , lookup
Economics of global warming wikipedia , lookup
Climate governance wikipedia , lookup
Effects of global warming on human health wikipedia , lookup
Citizens' Climate Lobby wikipedia , lookup
Climate engineering wikipedia , lookup
Global warming controversy wikipedia , lookup
General circulation model wikipedia , lookup
Climate change and agriculture wikipedia , lookup
Media coverage of global warming wikipedia , lookup
Fred Singer wikipedia , lookup
Climate change in Tuvalu wikipedia , lookup
Effects of global warming wikipedia , lookup
Global warming hiatus wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
Climate change in Canada wikipedia , lookup
United Nations Framework Convention on Climate Change wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Carbon Pollution Reduction Scheme wikipedia , lookup
Climate change and poverty wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Climate change, industry and society wikipedia , lookup
Global Energy and Water Cycle Experiment wikipedia , lookup
Physical impacts of climate change wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
Global warming wikipedia , lookup
Climate change in the United States wikipedia , lookup
Solar radiation management wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Politics of global warming wikipedia , lookup
Climate change feedback wikipedia , lookup
18 Global Climate Change Chapter Objectives This chapter will help students: Describe Earth’s climate system and explain the many factors influencing global climate Characterize human influences on the atmosphere and global climate Summarize modern methods of climate research Outline current and future trends and impacts of global climate change Suggest ways we may respond to global climate change Lecture Outline I. Central Case: Rising Seas May Flood the Maldives Under A. A nation of low-lying islands, or atolls, in the Indian Ocean, the Maldives is known for its spectacular tropical setting, colorful coral reefs, and sun-drenched beaches. B. Nearly 80% of the Maldives’ land area of 300 km2 lies less than 1 m (39 in.) above sea level, and the highest point of ground is only 2.4 m. C. The world’s oceans rose 10–20 cm (4–8 in.) this past century, and are expected to continue to rise as temperatures warm, causing melting ice caps to discharge water into the ocean. D. The island’s government has evacuated residents from several of the lowest-lying islands in recent years. E. The tsunami in December of 2004 destroyed large sectors of the islands, including both homes and infrastructure such as hospitals and modes of transportation. F. Other effects included soil erosion, saltwater contamination of aquifers, and other environmental damage. G. The tsunami was caused by an earthquake, but the rising sea level allowed it to inflict great damage on the low-lying islands. H. Maldives islanders are not alone in their worries; the people of other island nations and mainland coastal areas of the world fear the future. IG-262 II. Our Changing Climate 1. Climate influences everything from daily weather, major storms, crop success, human health, ecosystem function, and even national security. 2. The 2007 report from the Intergovernmental Panel on Climate Change shows wide scientific consensus that global climate is changing rapidly and human action is the major cause. A. What is climate change? 1. Climate is an area’s long-term weather. 2. Changes in the long-term pattern of atmospheric conditions worldwide, involving temperature, precipitation, and storm frequency and intensity, are global climate change. 3. Global warming refers specifically to increasing surface temperatures of the Earth and is but one aspect of global climate change. B. The sun and the atmosphere keep Earth warm. 1. The sun, the atmosphere, and the oceans exert more influence on Earth’s climate than all other factors combined. C. “Greenhouse gases” warm the lower atmosphere. 1. As Earth’s surface absorbs solar radiation, its temperature increases and it emits radiation in the infrared portion of the spectrum. 2. Some atmospheric gases absorb infrared radiation effectively and are known as greenhouse gases. 3. When these gases absorb heat, they warm the atmosphere (specifically, the troposphere) as well as Earth’s surface. This warming is known as the greenhouse effect. 4. The greenhouse effect is a natural phenomenon that has been increased through human activities. D. Carbon dioxide is the greenhouse gas of primary concern. 1. Although carbon dioxide is not the most potent greenhouse gas on a per-molecule basis, its abundance in the atmosphere means that it contributes more to the greenhouse effect than other gases. 2. Carbon dioxide concentrations have increased and are currently at the highest level in at least 650,000 years if not in the last 20 million years. 3. In the last two centuries humans have been burning increasing amounts of fossil fuels in their homes, factories, and automobiles. At the same time we have cleared and burned forests, reducing the biosphere’s ability to absorb carbon dioxide from the atmosphere. E. Other greenhouse gases add to warming. 1. Other greenhouse gases are increasing in the atmosphere. a. We release methane into the atmosphere by tapping into fossil fuel deposits, raising large herds of cattle, disposing of organic matter in landfills, and growing certain types of crops, including rice. b. Nitrous oxide is a by-product of feedlots, chemical manufacturing plants, auto emissions, and modern agricultural practices. IG-263 c. Ozone concentrations in the troposphere have increased by 36% since 1750. d. The contribution of halocarbon gases to global warming is lower now due to the Montreal Protocol of 1987. e. Water vapor is the most abundant greenhouse gas, and its concentration increases as tropospheric temperatures rise. F. Aerosols may exert a cooling effect on the lower atmosphere. 1. Microscopic droplets and particles can have either a warming or a cooling effect. Most tropospheric aerosols, such as the sulfate aerosols produced by fossil fuel combustion, may slow global warming in the short term. G. Radiative forcing expresses change in energy input over time. H. The atmosphere is not the only factor that influences climate. 1. Milankovitch cycles are changes in Earth’s rotation and orbit around the sun, and they result in slight changes in the relative amount of solar radiation reaching Earth’s surface at different latitudes. 2. The sun varies in the amount of radiation it emits over short and long time scales. This is referred to as solar output. 3. Ocean absorption. a. The oceans absorb carbon dioxide directly from the atmosphere through direct solubility of gas in water. b. Marine phytoplankton also uptake carbon dioxide for photosynthesis. 4. Oceanic circulation also shapes climate. a. El Niño conditions occur when equatorial winds weaken and allow warm water from the western Pacific to move eastward, eventually preventing cold water from welling up in the eastern Pacific. b. In La Niña events, cold surface waters extend far westward in the equatorial Pacific. c. Many scientists today are exploring whether globally warming air and sea temperatures may be increasing the frequency and strength of El Niño events. d. Ocean currents and climate also interact through the thermohaline circulation, a worldwide current system in which warmer, fresher water moves along the surface and colder, saltier water moves deep benearh the surface. e. North Atlantic Deep Water (NADW) is part of a circulation pattern that moves warm surface water northward toward Europe where cooler water then sinks and returns in the other direction. III. Studying Climate Change A. Proxy indicators tell us about the past. 1. Ice caps and glaciers have preserved tiny bubbles of ancient atmosphere. IG-264 2. Sediment beds beneath bodies of water can be analyzed to learn about the ancient vegetation in an area and, by extension, what the climate was like at the time. 3. These sources of indirect evidence, which substitute for direct measurements, are called proxy indicators. 4. Other proxy indicators include coral reefs and tree rings. B. Direct atmospheric sampling tells us about the present. 1. Charles Keeling of the Scripps Institution of Oceanography documented trends in atmospheric carbon dioxide concentrations starting in 1958. 2. Keeling’s data show that atmospheric carbon dioxide concentrations have increased from around 315 ppm to 383 ppm since 1958. C. Models help us understand climate change. 1. Coupled general circulation models (CGCMs) are computer programs that combine what is known about weather patterns, atmospheric circulation, atmosphere–ocean interactions, and feedback mechanisms to simulate climate processes. 2. Over a dozen research labs around the world operate CGCMs. 3. Tests suggest that today’s computerized models provide a good approximation of the relative effects of natural and anthropogenic influences on global climate. IV. Current and Future Impacts 1. Evidence that climate conditions have changed worldwide since industrialization is now overwhelming and indisputable. 2. Climate change has already had effects on the physical properties of the planet and if we continue to emit greenhouse gases, the effects will be more severe. A. The IPCC report summarizes evidence of climate change and predicts future impacts. 1. The 2007 assessment of the IPCC summarized thousands of scientific studies on climate change and documents observed trends in surface temperature, rainfall patterns, snow and ice cover, sea levels, storm intensity, and other factors. 2. The report included a series of possible climate change scenarios and what strategies we might use to respond to these changes in climate. B. Temperature increases will continue. 1. The IPCC report concludes that average surface temperatures on Earth increased by an estimated 0.74 °C (1.33 °F) in the century from 1906 to 2005, with most of this increase occurring in the last few decades. 2. Temperature increases are greatest in the arctic, causing glaciers to shrink and disappear in the arctic and in many areas around the world. Polar ice shelves are melting. This, combined with the warming temperature resulting in expansion of the water, is causing a rise in sea level. 3. Scientists are not yet sure, but recent analyses of storm data suggest that warmer seas may not be increasing the number of IG-265 C. D. E. F. G. storms, but likely are increasing the power of storms, and possibly their duration. Changes in precipitation vary by region. 1. Some areas will receive more rainfall and others will receive less. 2. Drought and floods are possible under these new conditions. Melting ice and snow have far-reaching effects. 1. As the world warms, mountaintop glaciers disappear. Since 1980, the World Glacier Monitoring Service estimates major glaciers have lost an average of 9.6 m (31.5 ft) in vertical thickness. Many glaciers on tropical mountaintops have disappeared already. 2. In the Arctic, as snow and ice melt, darker less-reflective surfaces are exposed and Earth’s albedo, or capacity to reflect light, decreases. More of the sun’s rays are absorbed at the surface and the surface warms. Rising sea levels will affect hundreds of millions of people. 1. As glaciers and ice sheets melt, increased runoff into the oceans causes sea levels to rise. 2. Seas rose by an estimated 1.8 mm/year from 1961–2003 and 3.1 mm/year from 1993–2003. 3. Vertical rise in sea level of several inches can represent many feet of horizontal incursion onto coastal lands. 4. Island nations are at great risk from events called storm surges, caused by high tides and winds caused by storms. 5. If Greenland’s melting continues to accelerate, then sea levels will.rise more quickly. Rising sea levels will force hundreds of millions of people to choose between moving upland or investing in costly protections against high tides and storm surges. Densely populated regions on low-lying river deltas, such as Bangladesh, will be most affected. Climate change affects organisms and ecosystems. 1. Organisms are adapted to their environment and are affected when the environment is altered. 2. Changes in timing of seasonal events such as temperaturedependent biological phenomena and the onset of spring are creating complex effects in ecosystems worldwide. 3. There are spatial shifts in the ranges of organisms as many plants and animals shift north to avoid hotter and drier conditions. 4. Species interactions will be affected. Climate change exerts societal impacts. 1. Agriculture—cuts in agricultural productivity are possible as droughts and floods increase. There could be a slight increase in productivity as plants respond to higher carbon dioxide levels. 2. Forestry—insects, disease outbreaks, invasive species, and catastrophic fires could all become more common. 3. Health—humans will experience more heat stress, tropical diseases, respiratory ailments, hunger when droughts occur, and compromised sanitation during flood events. 4. Economics—IPCC data suggest that global climate change will cost nations between 1 to 5% of GDP. IG-266 H. Impacts will vary regionally. I. Are we responsible for climate change? 1. The IPCC reports that it is greater than 90% that the current global climate change is caused by humans. 2. The scientific understanding of climate change is clear enough to justify nations taking immediate action. 3. In the United States, a small group of “greenhouse skeptics” drove the debate and prevented the nation from taking swift action. These “skeptics” derived significant funding from corporate entities in the oil, coal, and other extractive industries. 4. Recently, there has been a change in public polling data and public perception such that even corporations are taking steps to address climate change issues by asking governments to enact legislation that would put caps on greenhouse gas emissions. V. Responding to Climate Change 1. Today, there is a new broad consensus that climate change presents great challenges to our society. A. Shall we pursue mitigation or adaptation? 1. Mitigation would involve actions that would reduce emissions of greenhouse gases. 2. Adaptation would involve acknowledging that climate change is happening and that we must search for ways that will modify and soften the blows. Adaptations can include building sea walls and restricting coastal development. 3. Mitigation and adaptation are not mutually exclusive although environmentalists charge that the adaptation approach is sometimes “escapist.” B. Electricity generation is the largest source of U.S. greenhouse gases. C. Conservation and efficiency. 1. Conservation and efficiency can arise from new technologies, or from individual ethical lifestyle choices. 2. Renewable sources of electricity can also reduce fossil fuel use. D. Sources of electricity. 1. Natural gas has less impact on global warming than oil or coal. 2. Carbon sequestration or storage would allow current practices to continue, provided carbon emissions are captured and stored. E. Transportation is the second largest source of U.S. greenhouse gases. 1. One-third of the average American city is devoted to use by cars—including roads, parking, garages, and gas stations. 2. The typical automobile is highly inefficient. Close to 85% of the fuel you use does something other than move your car down the road. 3. Automotive technology is making possible alternatives such as electric vehicles, alternative fuels, hybrid vehicles, and hydrogen fuel cells. 4. Driving less and using public transportation are lifestyle choices that reduce reliance on cars. F. Automotive technology. IG-267 G. H. I. J. K. L. 1. Government mandates, consumer demand, and higher fuel prices will stimulate technology that will create fuel efficiency. Driving less and public transportation. 1. Choosing where to live to reduce travel distance to work and school will save energy. 2. Increasing public transportation options is the single most effective strategy for conserving energy and reducing pollution. We can reduce emissions in other ways. 1. Sustainable agriculture and land management that protects the integrity of soil on cropland and rangeland enables soil to store more carbon. 2. Reducing methane emissions from rice fields and cattle, and reducing certain fertilizers are important techniques. 3. Preserving existing forests and increasing the rate of reforestation will pull more carbon from the atmosphere. 4. Recovering methane from landfills and treating wastewater and generating energy from solid waste incineration also reduce emissions of global warming gases. We will need to follow multiple strategies to reduce emissions. Shall we use government mandates or market incentives? 1. At all levels, policymakers, industry, commerce, and citizens are searching for ways to employ government AND markets to reduce emissions in ways that are fair, economically palatable, effective, and enforceable. We began tackling climate change by international treaty. 1. In 1992, the United Nations convened the United Nations Conference on Environment and Development Earth Summit in Rio de Janeiro. Five documents were signed, including the U.N. Framework Convention on Climate Change (FCCC), which outlined a plan for reducing greenhouse gas emissions through a voluntary, nation-by-nation approach. a. In the U.S., greenhouse emissions increased by over 13% in the 10 years following the Rio conference. b. Germany and the United Kingdom both cut their greenhouse gas emissions by 13% to 18% during the same period. c. The decision was made to create a binding international treaty that would require all signatory nations to reduce greenhouse gas emissions. This is the Kyoto Protocol. The Kyoto Protocol seeks to limit emissions. 1. The Kyoto Protocol was to take effect when nations responsible for 55% of global greenhouse emissions ratified it. That occurred in 2005 when Russia became the 127th nation to sign. 2. The United States, the world’s largest emitter of greenhouse gases, refuses to ratify the protocol, claiming it is unfair to industrialized nations. 3. Proponents of the Kyoto Protocol point out that the even with compliance to the Kyoto Protocol, emissions would continue to increase, but will not increase as quickly. All signatory nations are IG-268 M. N. O. P. looking beyond Kyoto to the next negotiation that will supercede Kyoto. States are advancing climate change policy. Market mechanics are being used to address climate change. 1. Programs such as cap and trade. Carbon offsets are in vogue. 1. A carbon offset is a voluntary payment to another entity intended to enable that entity to reduce the greenhouse emissions that one is unable or unwilling to reduce oneself. 2. In theory, carbon offsets are a good idea but they also fall short of the goal in practice since there are not rigorous inspection and enforcement actions. You can reduce your own carbon footprint. 1. Collective action by global citizens is necessary to change future outcomes of reducing our carbon footprint on the planet. VI. Conclusion A. Many factors, including human activities, can shape atmospheric composition and global climate. B. Scientists and policymakers are beginning to understand anthropogenic climate change and its environmental impacts more fully. C. Reducing greenhouse gas emissions and taking other actions to mitigate and adapt to climate change represents the foremost challenge for our society in the coming years. Key Terms albedo carbon offset El Niño global climate change greenhouse effect greenhouse gas Intergovernmental Panel on Climate Change (IPCC) Kyoto Protocol La Niña Milankovitch cycle proxy indicator solar output storm surge thermohaline circulation United Nations Framework Convention on Climate Change (FCCC) Teaching Tips IG-269 1. Provide students with detailed information about paleoclimate proxy data. The National Oceanic and Atmospheric Administration (NOAA) Paleoclimatology Program website (www.ngdc.noaa.gov/paleo/slides.html) provides detailed information about paleoclimate proxy data. There are online slide sets with photographs of field research, important data sets, and descriptive diagrams appropriate for college-level courses. The available slide sets for paleoclimatology are The Ice Ages, Climate and the Classic Maya Civilization, Coral Paleoclimatology, Polar Ice Cores, Packrat Middens, Tree Rings, Heinrich Events, and Low Latitude Ice Cores. A ninth set, Rock Varnish, is available only as 35-mm slides at this time, but may be online in the near future. Have groups of your students create either a poster or a PowerPoint presentation about the above topics. You may want to include the study of fossil pollen from core samples (paleopalynology— www.geo.ucalgary.ca/~macrae/palynology is a good reference site). NOAA’s website (www.ngdc.noaa.gov/paleo/ctl/glossary.html) provides an excellent glossary of climate terms as well as an overview of a climate timeline. 2. In January 1998, a team of scientists from Russia, the United States, and France retrieved a deep ice core near the Russian Vostok station in east Antarctica. Preliminary data show that the ice core extends through four climate cycles, with the oldest ice more than 400,000 years old. Ask students to graph the carbon dioxide data from the ice core. The report was published in Nature (Petit, J. R., et al., Nature v. 399 (6735), pp. 429– 436, 1999). The data can be downloaded from www.ngdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok.html. Ask students the following questions: • Are climate cycles evident? • How did the temperature change with the carbon dioxide cycles? • Is the carbon dioxide concentration today higher or lower than those recorded in the ice core? 3. Energy Star (www.energystar.gov) is a government-backed program helping businesses and individuals to protect the environment through superior energy efficiency. There are home and business products in over 40 categories eligible for the Energy Star designation. In general, these products use less energy, cost less money to operate, and protect the environment. Ask students to choose a product that they will likely buy over the next year. Assign them to search the Energy Star website for the criteria required for that product, and ask them to share that information with the rest of the class. IG-270 4. Have your students learn more about how tree-ring research helps us to understand ancient climates, fire ecology, activities and impacts of early humans, global warming, and many other topics. The Laboratory of Tree-Ring Research (www.ltrr.arizona.edu) has online lessons about tree-ring basics and a tutorial called “Try Crossdating Yourself,” which teaches students how scientists match and crossdate tree rings from many samples in both local and wide-ranging areas to gather information about both small events (e.g., a local insect infestation) and large ones (e.g., a severe drought). There are a series of online exercises that can be printed out and used as homework or as lab exercises. There are also numerous links to research publications and subtopics such as dendroecology and dendroclimatology. 5. Ask students to examine statements from their power company, surveying several months of data, if possible. Answer the following questions: Is there a difference in the kilowatt hours used from one month to the next? If there is a difference, what are some reasons for the differences? Ask students to predict which appliance, system, or activity in their homes accounts for the most power use. Invite a representative from a local utility to visit the classroom if that utility offers a free home energy audit. Have the guest speaker explain the benefits of a home energy audit and allow students to ask questions and perhaps schedule an audit for their home or rental property. 6. A common frustration that instructors share is over how much material they should present to their students for a particular course. When faced with a wide range of possible topics, the temptation for instructors is to include as many topics as possible, in as much depth as possible, which may result in a low level of student understanding and retention, as demonstrated by low exam grades. Extensive research has investigated the way that people learn “chunks” of data in a discipline, examining the differences between learning while a novice and learning once a more expert status is attained, and how different types of learners make the mental connections required to develop the broader associations to form larger chunks of data. The research shows that it is possible for most people to take in only somewhere between three and seven new chunks of data at one time, with five usually being the optimal number. The size of these chunks differs greatly, however, between novices and experts. For example, a novice chunk might be a single new definition, whereas an expert chunk could be an entire concept built around that already well-understood definition plus three others. IG-271 The take-home message for instructors is to first determine the amount of information that forms a “chunk” for your students, and then to prepare a lesson with about three to five of these chunks—certainly never more than seven—in a single day, with some way to review those bits of information before going on to the next lesson. Additional Resources Websites 1. Global Warming Site, Environmental Protection Agency (EPA) (http://yosemite.epa.gov/OAR/globalwarming.nsf/content/index.html) This website has national and international information about climate, greenhouse emissions, potential impacts, actions, and links to other resources. 2. Global Warming, Earth Observatory, National Aeronautics and Space Administration (NASA) (http://earthobservatory.nasa.gov/Library/GlobalWarming/warming.html) This NASA web reference site gives basic information about global warming, summarizes the skeptics’ point of view, and describes NASA’s global climate change projects. 3. NOAA-CIRES Climate Diagnostics Center, National Oceanic and Atmospheric Administration (NOAA), Department of Commerce (www.cdc.noaa.gov/ClimateInfo/tools.html) This web resource provides a gateway to data and basic information about climate and climate assessment. 4. Intergovernmental Panel on Climate Change, The United Nations Environment Programme (UNEP) and World Meteorological Organization (WMO) (www.ipcc.ch) The official IPCC website has information about IPCC and its activities, publications, press releases, and official documents. 5. Climate Prediction Center, The National Weather Service (NWS), NOAA, Department of Commerce (www.cpc.ncep.noaa.gov) This part of the National Weather Service website is dedicated to presenting climate data, models, and statistical analyses to predict future climate trends. Audiovisual Materials 1. Global Warming Series, distributed by The Video Project (http://videoproject.com) IG-272 This four-part series clearly illustrates exactly what global warming is, what we are doing to cause it, and why it is dangerous. 2. Rising Waters: Global Warming and the Fate of the Pacific Islands, 2000, produced by the Independent Television Service and Pacific Islanders in Communications, distributed by Bullfrog Films (www.bullfrogfilms.com) This video examines the problem of global climate change by showcasing the personal stories of Pacific Islanders. 3. Turning Down the Heat, 1999, produced by Jim Hamm Productions and distributed by Bullfrog Films (www.bullfrogfilms.com) This film profiles innovative alternative energy projects such as solar energy in Holland and biogas in Denmark and Vietnam. 4. Be Prepared for Global Warming, 2003, distributed by Films for the Humanities & Sciences (www.films.com) This program examines how land and populations made vulnerable by rapidly rising worldwide temperatures are protected. 5. The Impact of Global Warming, 2000, distributed by Films for the Humanities & Sciences (www.films.com) This program travels the world to observe how global warming, accelerated and exacerbated by air pollution, is affecting society. 6. An Inconvenient Truth: A Global Warning. (2006). 96 minutes PG. An Academy Award–winning film by Vice President Al Gore. A compelling view of the future of Planet Earth—and human civilization. Touted as a wakeup call that cuts through the myths and misconceptions to deliver the message that global warming is a real and present danger, the film brings home Al Gore’s message that we must act now to save the Earth. In end-of-term surveys, after several terms of showing this film, students rate it as one of the most important experiences they take away from the class. It is important to allow time for students to decompress and debrief after viewing this film. Weighing the Issues: Facts to Consider Agriculture in a Warmer World Facts to consider: Analysts are divided about whether the shift in agricultural locations due to global climate change will raise or lower global agricultural output. Since many countries in higher latitudes tend to be more developed nations and are more equipped to operate agriculture at higher rates of productivity, more food ought to be produced. On the other hand, much of the arable land in wealthier countries may have already been developed for urban areas, so some food-production potential may not be realized. IG-273 If agriculture shifts northward, poorer nations may become even weaker economically. These impoverished governments, already unable to provide basic needs to their population, may become overwhelmed, heightening the possibility of political unrest and war. Fighting may take place over essential resources such as freshwater and useful agricultural land. The gap between rich and poor nations may grow even wider as the mainly agrarian societies of developing countries become subject to even harsher environmental conditions for growing crops. It is also possible that such nations could make positive adaptations, such as increasing use of water-conserving irrigation techniques and cultivating crops that need less water. However, such change requires massive amounts of funding, and may not happen due to a lack of liquid capital. Finally, if current mid-latitude areas are less able to produce food because of hostile environmental conditions, then northern lands, now left wild, may become farms. Land use conflicts may also rise in the north between environmental, developmental, and agricultural concerns. Environmental Refugees Facts to consider: Reponses will vary. Those who believe that climate change is uncertain or part of a natural cycle would not be influenced by refugee flow, and may posit that the rise in sea level is temporary, thus allowing refugees to return to Tuvalu. It could be argued that Tuvalu islanders may have wanted to become part of a more developed country such as New Zealand and are using their refugee status to accomplish this goal at the expense of the host country. A Tuvalu resident would tend to look at this issue in human, social, and cultural-survival terms, stating that it is not fair that the actions of others are having such a devastating effect on their island nation. A U.S. oil industry executive, though sympathetic, might argue that far fewer people have been disturbed than would be if fossil fuel use were curtailed to the point that would be required to reverse global warming. The economic and social dislocations caused by this shift would be on a more massive scale than what has occurred in island nations. To save their way of life, people in Tuvalu or the Maldives might try to build seawalls, build homes on stilts, and construct other structures that will reduce the damage caused by storm surges. They may develop tourist-oriented markets to help expose people from developed countries to the value of their island nation, thus making them aware of the threat that the island nation faces and potentially making them advocates on the island’s behalf. They can take steps toward restoring the coral reefs in order to compensate for the damage being done by storm surges. They can build alliances with other island nations and developed countries to gain international recognition and political clout. Residents of coastal Florida could also build seawalls and structures to reduce storm surge damage, and will likely be better able than the island nation citizens to do so because of their greater wealth. The Precautionary Principle IG-274 Facts to consider: Most of the answers to these questions will require an individual response. On a practical level, economics will have to play a significant role in the discussion. Many of the most developed arguments against applying the precautionary principle to the issue of global climate change focus on the economic costs of decreasing or eliminating fossil fuel use as well as on the social consequences that these economic costs could bring. Those arguing for the precautionary principle could cite economic factors that favor their approach, such as the economic benefits of maintaining established agriculture wherever it exists, especially in developing countries. Land and coastline loss, health impacts, human relocations, and other effects of global climate change can also be cited for their negative economic consequences. Interestingly, the Tragedy of the Commons can be applied to both lines of argument, with the difference between the arguments being whether the students feel that short- or long-term results are more important. The Science behind the Stories: Thinking Like a Scientist Understanding El Niño and La Niña Hypothesis: Increased global air and ocean surface water temperatures are responsible for the increasing frequency of El Niño and La Niña events in the Pacific Ocean. Monitoring: Scientists analyzed data from a system of buoys that make up the Tropical Atmosphere Ocean Project, also known as the TAO/TRITON. These buoys are anchored across the Pacific Ocean along the equator and monitor oceanic wind direction and surface water temperatures. Scientists use the data to construct temperature and wind direction profiles of the equatorial Pacific Ocean during normal and El Niño conditions. Application: The profiles constructed by scientists are used to predict the extent and severity of El Niño events. These predictions allow governments and individuals to better prepare for extreme weather conditions and changes in ocean conditions. Implication: Analyses of the data from these buoys clearly show the integration among the atmosphere, the oceans, and regional and global climate by furthering our understanding of the connections among El Niño and La Niña events, climate change, and their effects on other environmental systems. Scientists Use Pollen to Study Past Climate Observation: Climate in an area can be studied by examining the types of vegetation that grow in the area. Past climates can be studied by examining plant remains in sediment cores from freshwater lakes and ponds. IG-275 Study: In the early 1990s, J. S. McLachlan of Harvard University and L. S. Brubaker of the University of Washington studied the past climate of Washington State’s Olympic Peninsula by examining plant remains in sediment cores taken from a cedar swamp and a small freshwater lake. Cores were taken from sample sites, wrapped in plastic and foil, and then frozen. A 1-mm-thick slice was cut from the core every 10 to 30 cm. The core slices were analyzed for large plant material, pollen, and charcoal, with pollen being the focus because of its resistance to biological decomposition and, because it is easily transported by wind, the fact that it allows for plant species to be identified over a large region. Macroscopic plant parts were identified and used to characterize the flora and climate of local areas, and charcoal was used to construct a history of forest fires. Using this correlation with regional historical climate data from other sources, and from the fact that the deeper a core is, the older the sediments are, a relative chronology could be determined. Results: A general plant and climate history of the Olympic Peninsula was constructed using plant species to determine whether warm, wet conditions were present in the past, or whether cold-loving plants revealed a cooler climate. InvestigateIt Case Studies and Videos Case Studies As Weather Shifts, Beaches May Pay a Heavy Price Eskimos Seek to Recast Global Warming as a Rights Issue How Drought Just Might Bring Water to the Navajo As the Seas Warm, Algae Help Some Coral Stand Up to the Heat Antarctic Glaciers Quicken Pace to Sea; Warming Is Cited Studies Find Atmosphere Is Warmer Japan Squeezes To Get the Most Of Costly Fuel Earth Has Become Brighter, but No One Is Certain Why At Australia’s Bunny Fence, Variable Cloudiness Prompts Location Topic Florida Oceans Buenos Aires, Argentina Ethics Navajo Nation, New Mexico Freshwater Res. Global Commons Oceans Alabama Global Warming Global Warming Japan Renewable Energy Switzerland Air Pollution Australian Outback Global Warming Antarctica IG-276 Region Australia Climate Study In Sweden, It's Global Warming vs. Big Heavy Cars The Climate Divide: Reports From Four Fronts in the War on Warming The Climate Divide: Reports From Four Fronts in the War on Warming The Climate Divide: Reports From Four Fronts in the War on Warming The Climate Divide: Reports From Four Fronts in the War on Warming Trying to Connect the Dinner Plate to Climate Change It's Maple Syrup Time, So Why the Whiff of French Fries? Sweden Global Warming Sweden Blantyre, Malawi Global Warming Malawi Perth, Australia Global Warming Australia Dhanaur, India Global Warming India Maasbommel, The Netherlands Global Warming Netherlands Illinois Global Warming Illinois Vermont Glaciers in Retreat India A Team of 2, Following the Scent of Polar Bears Canada Russia's Strategy: Save Polar Bears With Legal Hunt A Passion for Soccer and the Environment Balmy Weather May Bench a Baseball Staple Videos The Day After Tomorrow Ethanol Myths Global Warming Global Warming Global Warming Vermont India Canada Vankarem, Russia Biodiversity Russia Colorado Urbanization Forestry, Global Warming Topic Global Warming Energy Colorado Pennsylvania Location New York, NY United States Pennsylvania Region Indiana Answers to End-of-Chapter Questions Testing Your Comprehension 1. Approximately 30% of incoming solar radiation is reflected back into space, and the other 70% is absorbed by the atmosphere or Earth’s surface. Outgoing heat radiation from the surface is absorbed by greenhouse gases in the lower IG-277 atmosphere, and then reradiated, warming the air. 2. Although carbon dioxide has a lower global warming potential than some other greenhouse gases, its abundance in the atmosphere gives it the most influence over climate of all gases whose concentrations are being increased by human activity. Water vapor is a greenhouse gas. Increased atmospheric water vapor could increase atmospheric warming by absorbing more outgoing infrared radiation, which would cause more evaporation and therefore more atmospheric water vapor, creating a positive feedback loop. However, it could also increase atmospheric reflectivity of incoming visible-wavelength solar radiation, which would result in less solar energy penetrating the atmosphere to warm the surface, thereby cooling the surface—a negative feedback effect. 3. The ancient atmosphere can be studied by extracting trapped air bubbles from cores bored through layers of accumulated ice in the polar ice caps and ice sheets. 4. Coupled general circulation models (CGCMs) have been effective aids in climate prediction, and results from them form the basis for most of the predictions in the influential IPCC assessment reports. Climate models work by modeling the physics of the transfer of matter and energy in the oceanatmosphere system. Modelers use known observed data to set parameters that enable the simulation and projection of future data. 5. Figure 18.12 lists many observed and predicted trends in climate and their impacts. Among these, five observed (current or past) trends include: (1) Earth’s average surface temperature has risen 0.74 °C (1.33 °F) in the past 100 years; (2) sea level rose by an average of 17 cm (7 in.) in the 20th century; (3) ocean water became more acidic by about 0.1 pH unit in the past century; (4) arctic areas have warmed the fastest of all regions; and (5) precipitation has increased in a number of regions (e.g., e. North America, e. South America, n. Europe, and n. and c. Asia), but has decreased in others (e.g., the Sahel, the Mediterranean, s. Africa, and parts of s. Asia). Projected future trends include: (1) Earth’s average surface temperature will rise 1.8–4.0 °C (3.2–7.2 °F) in the 21st century; (2) sea level will rise 18–59 cm (7–23 in.) in the 21st century; (3) ocean water will decrease in pH by 0.14–0.35 units by century’s end; (4) species ranges will continue to shift toward the poles and upward in elevation, and the timing of seasonal phenomena such as migration and breeding will continue to shift; and (5) the melting of mountain glaciers will reduce water supplies to millions of people. 6. Rising sea levels can flood coastal areas, causing the loss of significant areas of coastal wetlands and forests, salt intrusion into coastal aquifers, and displacement of coastal inhabitants in the face of increased danger and property damage from storm surges and flooding. Coastal ecosystems will be affected in various ways by rising sea levels. Coral reef ecosystems will be degraded or may disappear in many areas, due in part to storm surges, but primarily because increasingly acidic water (from the absorption of atmospheric carbon dioxide) will kill corals (and thereby threaten the diverse array of organisms that depend on coral reefs). 7. Drought, flooding, and temperature extremes in some areas may threaten agriculture, but longer growing seasons in other areas may increase productivity. The IPCC predicts that temperate-zone crop yields will rise until temperature warms beyond 3 °C (5.4 °F), but that in the dry tropics and subtropics, crop productivity will fall and lead to hunger. Species of plants IG-278 and animals (and entire forest communities) are already beginning to shift toward the poles and upward in elevation. As for human health, the hazards of heat stress, the spread of tropical diseases, flooding of sewage treatment systems, injuries, and storm-related drowning should all increase under a warmer global climate. There should, however, be fewer cold-climate-related diseases and injuries. Researchers project that negative health impacts will outweigh positive health impacts, but there is much uncertainty in this. 8. U.S. greenhouse gas emissions come primarily from the combustion of fossil fuels to generate electricity and from the combustion of fossil fuels to power transportation (cars, trucks, etc.). In both cases, the demand for the product (electricity, mobility) is considerable, and growing. We can reduce emissions in each case by reducing demand, increasing efficiency, and substituting alternative technologies that release fewer greenhouse gases. 9. International treaties set goals and introduce a level of accountability for nation-states. They may also exert some political or economic pressure to persuade countries to achieve those goals. The U.N. Framework Convention on Climate Change (1992) and the Kyoto Protocol (1997) are two examples of attempts to reduce greenhouse gas emissions. 10. Emissions trading systems (also referred to as permit-trading or cap-and-trade systems) are a major market-based approach for reducing greenhouse gas emissions. In these systems, governments set limits on overall emissions levels; issue permits to emit to companies, corporations, and utilities; and let the emitting parties buy, sell, and trade permits among themselves. Emissions trading systems may work well because the private sector can often achieve goals in an efficient manner with fewer costs. They may not work well if they allow hotspots of pollution or if government fails to design the system in a way that gives polluters adequate incentives to reduce pollution. Another way in which the free market is used to reduce emissions is through carbon offsetting, in which one party pays another to reduce greenhouse emissions. This approach can be efficient and appealing, but will work only if there is oversight and enforcement that guarantees that the offset funds achieve what they aim to achieve. Interpreting Graphs and Data 1. The approximate percent changes in CO2 emissions from transportation, electricity generation, and residential, commercial, and industrial primary energy use between 1980 and 2006 are 36%, 53%, –8%, –13%, and –20%, respectively. Each is calculated using the formula: % change = ( ((2006 emissions/1980 emissions) –1) × 100). 2. Between 1980 and 2006, CO2 emissions per capita decreased in all sectors except electricity generation and transportation. Similarly, CO2 emissions per unit of total economic activity decreased in all sectors over that time period. 3. Since transportation and electricity generation are the biggest producers of CO2 emissions and have shown the least improvement in efficiency, they are arguably the sectors where the greatest gains can still be made. Increased CAFE (automotive fuel efficiency) standards would be one effective strategy to spur efficiency in transportation. Support of low-emissions technologies and approaches for power generation (such as using power sources less IG-279 carbon-intensive than coal), would be an effective course of action to take for electricity generation. Calculating Ecological Footprints Person Carbon footprint (kg per person per year) 4,000 11,000 19,000 Answers will vary 2,000 World average Average for industrialized nations U.S. average Your footprint Average needed to halt climate change Your footprint with three changes Answers will vary [NOTE: Figures in the table are current as of August 2007, and may vary subsequently. Questions should be addressed using values given by the footprint calculator at the time the quiz is taken, and not to the potentially outdated values shown here.] 1. Answers will vary. Students may have larger or smaller footprints than the average U.S. resident, but most will have substantially larger footprints than the average person in the world. The consumption-intensive North American lifestyle accounts for this, particularly our auto transportation, electrical use, air travel, and industrialized agriculture. 2. Answers will vary. Changes in choice of a place to live and auto and jet travel will make relatively large differences. 3. Answers will vary, but achieving complete carbon neutrality will be very difficult. Purchasing carbon offsets will likely be necessary for most people. IG-280