Figure 19.2: S cience. The global average temperature of the atmosphere near the earth’s surface has changed significantly over different periods of time. The two graphs in the top half of this figure are rough estimates of long - and short-term global average temperatures, and the two graphs on the bottom are estimates of changes in the average temperature of the earth’s lower atmosphere over thousands of years. They are based on scientific evidence that contains gaps, but they do indicate general trends. Question: Assuming these are good estimates, what are two conclusions you can draw from these graphs? (Data from Goddard Institute for Space Studies, Intergovernmental Panel on Climate Change, National Academy of Sciences, National Aeronautics and Space Administration, National Center for Atmospheric Research, and National Oceanic and Atmospheric Administration)
Figure 19.3: Science. Ice cores are extracted by drilling deep holes into ancient glaciers at various sites such as this one (left) near the South Pole in Antarctica. Thousands of these ice cores, containing valuable climate and other data, are stored in places such as the National Ice Core Laboratory in the U.S. city of Denver, Colorado (right). Scientists analyze tiny air bubbles, layers of soot, and other materials trapped in different layers of these ice cores to uncover information about the past composition of the lower atmosphere, temperature trends such as those shown in Figure 19-2, greenhouse gas concentrations, solar activity, snowfall, and forest fire frequency .
Figure 19.4: S cience. Atmospheric levels of carbon dioxide (CO 2 ) and methane (CH 4 ), as well as the global average temperature of the atmosphere near the earth’s surface and the average global sea level have changed drastically over the past 400,000 years. These data were obtained by analysis of ice cores removed at Russia’s Vostok Research Station in Antarctica. More recent ice core analyses from Antarctica in 2007 indicate that current levels of CO 2 in the atmosphere are higher than at any time during the past 800,000 years. Carbon dioxide remains in the atmosphere for 80–120 years compared to about 15 years for methane. However, each molecule of methane has 25 times the warming potential of a molecule of carbon dioxide. These curves show general correlations between these different sets of data but do not establish a direct relationship among these variables. Question: What are two conclusions that you can draw from these data? (Data from Intergovernmental Panel on Climate Change, National Center for Atmospheric Research, and F. Vimeux et al., Earth and Planetary Science Letters , vol. 203 (2002): 829–843)
Figure 19.5: This graph compares atmospheric concentrations of carbon dioxide (CO 2 ) and the atmosphere’s average temperature for the period 1880–2009. The temperature data show the average temperature by year as well as a mean of these data. While the data show an apparent correlation between these two variables, they do not firmly establish such a correlation. (Data from Intergovernmental Panel on Climate Change, NASA Goddard Institute for Space Studies, and NOAA Earth System Research Laboratory)
Figure 19.6: Much of Alaska’s Muir Glacier in the popular Glacier Bay National Park and Preserve melted between 1948 and 2004. Mountain glaciers are now slowly melting throughout much of the world. Question: How might melting glaciers in Alaska and other parts of the world affect your life?
Figure 19.7: The big melt: Each summer, some of the floating ice in the Arctic Sea melts and then refreezes during winter. But in most recent years, rising average atmospheric and ocean temperatures have caused more and more ice to melt during the summer months. Satellite data show a 39% drop in the average cover of summer arctic sea ice between 1979 and 2007. In 2007 alone, the sea ice shrank by an area that was 6 times that of California, much more than in any year since 1979 when scientists began taking satellite measurements. If this trend continues, this summer ice may be gone by 2040, according to researchers Muyin Wang and James Overland, and perhaps earlier, according to a 2007 estimate made by NASA climate scientist Jay Zwally. Question: Do you think that the increased melting of floating arctic sea ice is part of a positive or negative feedback loop (see Figure 2-18, p. 49 and Figure 2-19, p. 50)? Explain. (Data U.S. Goddard Space Flight Center, NASA, National Snow and Ice Data Center )
Figure 19.7 Some projected effects of global warming and the resulting changes in global climate, based on the extent of warming and the total atmospheric concentrations of greenhouse gases in parts per million. According to the IPCC, a warming of 2 C° (3.6 F°) over 2005 levels is unavoidable, and an increase of at least 3 C° (5.4 F°) is likely sometime during this century (Figure 19-B). (Data from 2007 Intergovernmental Panel on Climate Change Report and Nicolas Stern, The Economics of Climate Change: The Stern Report, Cambridge University Press, 2006)
Figure 19.A: S cience. This is a simplified model of some major processes that interact to determine the average temperature and greenhouse gas content of the lower atmosphere and thus the earth’s climate. Red arrows show processes that warm the atmosphere and blue arrows show those that cool it. Question: Why do you think a decrease in snow and ice cover is adding to the warming of the atmosphere?
Figure 19.B: S cience. This figure shows estimated and measured changes in the average temperature of the atmosphere at the earth’s surface between 1860 and 2008, and the projected range of temperature increase during the rest of this century ( Concept 19-1 ). (Data from U.S. National Academy of Sciences, National Center for Atmospheric Research, Intergovernmental Panel on Climate Change, and Hadley Center for Climate Prediction and Research )
Figure 19.9: This photo shows the melting and retreat of the Athabasca Glacier in the Canadian province of Alberta between 1992 and 2005.
Figure 19.10: This figure shows a projected decrease in arctic tundra (see Figure 7-11, bottom, p. 157) in portions of eastern Russia between 2004 and 2100 as a result of atmospheric warming. The melting of permafrost in such tundra soils could release the greenhouse gases CH 4 and CO 2 , and accelerate projected climate disruption, which would melt more tundra. This loss of arctic tundra could reduce grazing lands for caribou and breeding areas for a number of tundra-dwelling bird species. (Data from Intergovernmental Panel on Climate Change and 2004 Arctic Climate Impact Assessment)
Figure 19.11: If the average sea level rises by 1 meter (3.3 feet), the areas shown here in red in the U.S. state of Florida will be flooded. (Data from Jonathan Overpeck and Jeremy Weiss based on U.S. Geological Survey Dat a)
Figure 19.12: For a low-lying island nation like the Maldives in the Indian Ocean, even a small rise in sea level could spell disaster for most of its 295,000 people. About 80% of the 1,192 small islands making up this country lie less than 1 meter (3.2 feet) above sea level. Rising sea levels and higher storm surges during this century could flood most of these islands and their coral reefs.
Figure 19.13: With warmer winters, exploding populations of mountain pine beetles have munched their way through large areas of lodgepole pine forest (orange-colored trees) in the Canadian province of British Columbia. Foresters are trying to reduce this threat by planting a mix of trees less susceptible to the pest—an example of applying the biodiversity principle of sustainability.
Figure 19.14: Areas in blue show counties in 28 U.S. states where one or both species of mosquitoes that transmit dengue fever have been found as of 2005. This supports the claim by some scientists that projected climate disruption will expand the range of mosquitoes that carry dengue fever, a debilitating and potentially deadly disease .
Figure 19.15: Environmental scientists have come up with this list of possible climate change tipping points. They urge us to focus on avoiding these thresholds beyond which large-scale, irreversible, and possibly catastrophic climate changes can occur. The problem is that we do not know how close we are to such tipping points.
Figure 19.E: Solutions. There are several proposed output methods for removing carbon dioxide from the atmosphere or from smokestacks and storing it in soil, plants, and deep underground reservoirs, as well as in sediments beneath the ocean floor. Questions: Which two of these solutions do you think would work best? Which two would be the least effective? Why?
Figure 19.17: Using carbon and energy taxes or fees to help reduce greenhouse gas emissions has advantages and disadvantages. Question: Which two advantages and which two disadvantages do you think are the most important and why?
Figure 19.18: Using a cap-and-trade policy to help reduce greenhouse gas emissions has advantages and disadvantages. Question: Which two advantages and which two disadvantages do you think are the most important and why?
Figure 19.19: I ndividuals matter. You can reduce your annual emissions of CO 2 . Question: Which of these steps, if any, do you take now or plan to take in the future?
Figure 19.20: S olutions. There are many ways for us to prepare for the possible long-term harmful effects of climate disruption. Questions: Which three of these adaptation plans do you think are the most important? Why?
Figure 19.22: Decreased levels of ozone in the stratosphere can have a number of harmful effects. ( Concept 19-4a ). Questions: Which three of these effects do you think are the most threatening? Why?
Figure 19.23: I ndividuals matter. You can reduce your exposure to harmful UV radiation. Question: Which of these precautions do you already take?
MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH Chapter 19 Climate Control and Ozone Depletion
Weather and Climate Are Not the Same• Weather is short-term changes • Temperature • Air pressure • Precipitation • Wind• Climate is average conditions in a particular area over a long period of time • Temperature • Precipitation • Fluctuations are normal
Climate Change is Not New (1)• Over the past 4.7 billion years the climate has been altered by • Volcanic emissions • Changes in solar input • Movement of the continents • Impacts by meteors • Changing global air and ocean circulation• Over the past 900,000 years • Glacial and interglacial periods http://www.youtube.com/watch?v=oJAbATJCugs
Climate Change is Not New (2)• Over the past 10,000 years • Interglacial period• Over the past 1,000 years • Temperature stable• Over the past 100 years • Temperature changes; methods of determination
Estimated Changes in the Average Global Temperature of the Atmosphere Fig. 19-2, p. 494
Science: Ice Cores Are Extracted by Drilling Deep Holes in Ancient Glaciers http://www.youtube.com/watch?v=oHzADl-XID8 Fig. 19-3, p. 495
Our Climate, Lives, and Economies Depend on the Natural Greenhouse Effect • Greenhouse gases absorb heat radiated by the earth • The gases then emit infrared radiation that warms the atmosphere • Without the natural greenhouse effect • Cold, uninhabitable earth
Human Activities Emit Large Quantities of Greenhouses Gases • Since the Industrial Revolution • CO2, CH4, and N2O emissions higher • Main sources: agriculture, deforestation, and burning of fossil fuels • Correlation of rising CO2 and CH4 with rising global temperatures
Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels Fig. 19-4, p. 496
Correlation of CO2 and Temperature Fig. 19-5, p. 497
CO2 Concentrations, 1960-2009 Figure 14, Supplement 9
Melting of Alaska’s Muir Glacier between 1948 and 2004 Fig. 19-6, p. 499
The Big Melt: Some of the Floating Sea Ice in the Arctic Sea Fig. 19-7, p. 499
Simplified Model of Some Major Processes That Interact to Determine Climate Fig. 19-A, p. 500
Comparison of Measured Temperature from 1860–2008 and Projected Changes Fig. 19-B, p. 501
CO2 Emissions Play an Important Role (1)• From burning fossil fuels and forests• Abetted by deforestation; forests remove CO2 from the atmosphere• 2010: 389 ppm• 2050: 560 ppm• 2100: 1,390 ppm• 450 ppm as tipping point
CO2 Emissions Play an Important Role (2)• Largest emitters, 2009 1. China 2. United States 3. European Union (27 countries) 4. Indonesia 5. Russia 6. Japan 7. India
Cumulative CO2 emissions, 1900-2005 Figure 15, Supplement 9
Waste Heat Also Plays a Role in Climate Disruption• Burning any fuel creates heat• Many sources of heat • Power plants • Internal combustion engines • lights
Enhanced Atmospheric Warming Could Have Serious Consequences• Worst-case scenarios • Ecosystems collapsing • Low-lying cities flooded • Wildfires in forests • Prolonged droughts • More destructive storms • Glaciers shrinking; rivers drying up • Extinction of up to half the world’s species • Spread of tropical infectious diseases
Severe Drought Is Likely to Increase• Accelerate global warming, lead to more drought• Increased wildfires• Declining streamflows, dry lakes, lower water tables• Dry climate ecosystems will increase• Other effects of prolonged lack of water
More Ice and Snow Are Likely to Melt (1)• Why will global warming be worse in the polar regions?• Mountain glaciers affected by • Average snowfall • Average warm temperatures • 99% of Alaska’s glaciers are shrinking• When mountain glaciers disappear, there will be far less water in many major rivers
More Ice and Snow Are Likely to Melt (2)• Glaciers disappearing from • Himalayas in Asia • Alps in Europe • Andes in South America• Greenland • Warmer temperatures
Shrinking Athabasca Glacier in Canada Fig. 19-9, p. 506
Permafrost Is Likely to Melt: Another Dangerous Scenario• If permafrost in Arctic region melts • Methane, a greenhouse gas, will be released into the atmosphere• Arctic permafrost contains 50-60x the amount of carbon dioxide emitted annually from burning fossil fuels• Methane in permafrost on Arctic Sea floor
Projected Decreases in Arctic Tundra in Russia, 2004-2100 Fig. 19-10, p. 507
Sea Levels Are Rising (1)• 0.8-2 meters by 2100• Expansion of warm water• Melting of land-based ice• What about Greenland?
Sea Levels Are Rising (2)• Projected irreversible effect • Degradation and loss of 1/3 of coastal estuaries, wetlands, and coral reefs • Disruption of coastal fisheries • Flooding of • Low-lying barrier islands and coastal areas • Agricultural lowlands and deltas • Contamination of freshwater aquifers • Submergence of low-lying islands in the Pacific and Indian Oceans and the Caribbean • Flooding of coastal cities
Areas of Florida to Flood If Average Sea Level Rises by One Meter Fig. 19-11, p. 507
Low-Lying Island Nation: Maldives in the Indian Ocean Fig. 19-12, p. 508
Extreme Weather Is Likely to Increase in Some Areas• Heat waves and droughts in some areas • Could kill large numbers of people• Prolonged rains and flooding in other areas• Will storms get worse? • More studies needed
Climate Disruption Is a Threat to Biodiversity (1)• Most susceptible ecosystems • Coral reefs • Polar seas • Coastal wetlands • High-elevation mountaintops • Alpine and arctic tundra
Climate Disruption Is a Threat to Biodiversity (2)• What about • Migratory animals • Forests• Which organisms could increase with global warming? Significance? • Insects • Fungi • Microbes
Exploding Populations of Mountain Pine Beetles in British Columbia, Canada Fig. 19-13, p. 509
Agriculture Could Face an Overall Decline• Regions of farming may shift • Decrease in tropical and subtropical areas • Increase in northern latitudes • Less productivity; soil not as fertile• Hundreds of millions of people could face starvation and malnutrition
A Warmer World Is Likely to Threaten the Health of Many People • Deaths from heat waves will increase • Deaths from cold weather will decrease • Higher temperatures can cause • Increased flooding • Increase in some forms of air pollution, more O 3 • More insects, microbes, toxic molds, and fungi
Detection of Dengue Fever in Mosquitoes, as of 2005 Fig. 19-14, p. 510
Dealing with Climate Disruption Is Difficult• Global problem with long-lasting effects• Long-term political problem• Harmful and beneficial impacts of climate change unevenly spread• Many proposed actions disrupt economies and lifestyles• Humans don’t deal well with long-term threats
Possible Climate-Change Tipping Points Fig. 19-15, p. 511
Science Focus: Science, Politics, and Climate• 2006-2010: increase from 30% to 48% of Americans who think global warming is exaggerated• Fossil fuel industries• Play on public’s lack of knowledge of • How science works • Difference between weather and climate
What Are Our Options?• Three approaches 1. Drastically reduce the amount of greenhouse gas emissions 2. Devise strategies to reduce the harmful effects of global warming 3. Suffer consequences of inaction
Prevent and Reduce Greenhouse Gas Emissions• Improve energy efficiency to reduce fossil fuel use• Increased use of low-carbon renewable energy resources• Stop cutting down tropical forests• Shift to more sustainable and climate-friendly agriculture
Collect Greenhouse Gas Emissions and Stash Them Somewhere• Solutions 1. Massive global tree planting; how many? 2. Restore wetlands that have been drained for farming 3. Plant fast-growing perennials on degraded land 4. Preserve and restore natural forests 5. Promote biochar 6. Seed oceans with iron to stimulate growth of phytoplankton 7. Carbon capture and storage – from coal-burning plants
Science Focus: Is Capturing and Storing CO2 the Answer? • Carbon capture and storage (CCS) • Several problems with this approach • Large inputs of energy to work • Increasing CO2 emissions • Promotes the continued use of coal (world’s dirtiest fuel) • Effect of government subsidies and tax breaks • Stored CO2 would have to remain sealed forever: no leaking
Some Propose Geo-Engineering Schemes to Help Slow Climate Change (1)• Last resort, if other methods and policies fail• Injection of sulfate particles into the stratosphere (scatters light) • Would it have a cooling effect? • Would it accelerate O3 depletion?• Giant mirrors in orbit around earth• Large pipes to bring nutrients from bottom of ocean to top to promote algae growth
Some Propose Geo-Engineering Schemes to Help Slow Climate Change? (2)• Doesn’t address the continued build-up of CO2 in the atmosphere• All depend on costly and complex plans• If any of these fixes fail, what about a rebound effect?
Governments Can Help Reduce the Threat of Climate Disruption 1. Strictly regulate CO2 and CH4 as pollutants 2. Carbon tax on fossil fuels 3. Cap-and-trade approach 4. Increase subsidies to encourage use of energy- efficient technology 5. Technology transfer
Trade-Offs: Carbon and Energy Taxes Fig. 19-17, p. 516
Trade-Offs: Cap and Trade Policies Fig. 19-18, p. 516
Some Governments Are Leading the Way• Costa Rica: goal to be carbon neutral by 2030• China and India must change energy habits• U.S. cities and states taking initiatives to reduce carbon emissions • California • Portland http://www.oregonlive.com/environment/index.ssf/2012/
What Can You Do? Reducing CO2 Emissions Fig. 19-19, p. 519
We Can Prepare for Climate Disruption (1) • Reduce greenhouse gas emissions as much as possible • Move people from low-lying coastal areas • Take measures against storm surges at coast • Cooling centers for heat waves • Prepare for more intense wildfires • Water conservation, and desalination plants
Ways to Prepare for the Possible Long-Term Harmful Effects of Climate Disruption Fig. 19-20, p. 520
A No-Regrets Strategy• What if climate models are wrong and there is no serious threat of climate disruption?• No-regrets strategy • Environmental benefits • Health benefits • Economic benefits • Reduce pollution and energy use • Decrease deforestation • Promote biodiversity
Why Should We Worry about Ozone Depletion?• Damaging UV-A and UV-B radiation • Increase eye cataracts and skin cancer• Impair or destroy phytoplankton • Significance?
Natural Capital Degradation: Effects of Ozone Depletion Fig. 19-22, p. 522
What Can You Do? Reducing Exposure to UV Radiation Fig. 19-23, p. 523