1. Climate Control and Ozone Depletion Chapter 19

2. 19-1 CIVILIZATION HAS EVOLVED DURING A PERIOD OF REMARKABLE CLIMATE STABILITY, BUT THIS ERA IS DRAWING TO A CLOSE. WE ARE ENTERING A NEW ERA, A PERIOD OF RAPID AND OFTEN UNPREDICTABLE CLIMATE CHANGE. THE NEW CLIMATE NORM IS CHANGE. LESTER R. BROWN

3. Global Warming and Global Cooling Are Not New Over the past 4.5 billion years the climate has been altered by Volcanic emissions Changes in solar input Movement of the continents Impacts by meteors Over the past 900,000 years Global Cooling and Global Warming Glacial and interglacial (between ice ages) periods Over the past 10,000 years Interglacial period-- stable climate and avg. Global surface temp Allowed agriculture and cities to flourish Over the past 1,000 years Temperature stable until we clear cut forests and burn fossil fuels Over the past 100 years Temperature changes methods of determination-radioisotopes in rocks, fossils and ocean sediment, boreholes, tree rings, etc

4. Estimated Changes in the Average Global Temperature of the Atmosphere

5. Our Climate, Lives, and Economies Depend on the Natural Greenhouse Effect Solar energy and the greenhouse effect warm the earth’s lower atmosphere and surface Without the natural greenhouse effect Cold, uninhabitable earth 1% of lower atmosphere is made of greenhouse gases (water vapor, CO 2, CH 4, and N 2 O) 1896 Arrhenius first recognized greenhouse effect Ice Cores Are Extracted by Drilling Deep Holes in Ancient Glaciers

6. Human Activities Emit Large Quantities of Greenhouses Gases Since the Industrial Revolution (275 years ago) CO 2, CH 4, and N 2 O emissions higher Main sources: agriculture, deforestation, and burning of fossil fuels Correlation of rising CO 2 and CH 4 with rising global temperatures CO 2 has risen from 280 ppm to 384 ppm

7. GREENHOUSE GASES CARBON DIOXIDE METHANE NITROUS OXIDE (N2O) CFCs WATER VAPOR

8. Greenhouse Gases CO 2 – most abundant greenhouse gas (GHG) Sources: burning fossil fuels, deforestation Ice cores have shown that CO 2 increasing in atmosphere – 35% higher than pre-Industrial Rev. Natural cycling of CO 2 levels Seasonal shift in CO 2 production; high fall; low spring Ocean acts as “sink,” absorbing large amounts. Vegetation acts as a sink (until it dies or is cut down) Stays in the atmosphere 50- 200

9. Other Greenhouse Gases Methane (CH 4 ) – 21 times more warming effect than CO 2 and increasing at 8 times the rate. Atmospheric lifetime= 12 years Methane production is faster than what is being broken down Main sources are wetlands, rice fields, fossil fuels, livestock

10. Greenhouse Gases Nitrous oxides – slow to breakdown Atmospheric lifetime = 120 years Provides 310 times more warming than CO 2 Sources are fossil fuels, fertilizers, deforestation CFCs– absorb 10,000 X more infrared than CO 2 Atmospheric lifetime = 100 + Sources are foams, aerosols, refrigerants, solvents Water vapor – Warmed by CO 2, the atmosphere is thus able to absorb more water vapor. And that water vapor, in turn, causes further warming—it amplifies the effects of carbon dioxide.

11. Human Activities Countries with the largest CO 2 emissions Per capita emissions of CO 2 Scientific and economic studies 2007: Field and Marland CO 2 will rise 3.3% a year Tipping point 2008: Aufhammer and Carson China’s CO 2 emission growth may be underestimated Ice core analysis of air pollutants 60% of CH 4 emission are a result of humans

12. Atmospheric Levels of CO 2 and CH 4, Global Temperatures, and Sea Levels Carbon Dioxide Methane Temp. Sea Level

13. The Atmosphere Is Warming Mostly Because of Human Activities 1988-Intergovernmental Panel on Climate Change (IPCC) 90–99% likely that lower atmosphere is warming 1906–2005: Ave. temp increased about 0.74˚C (1.3˚F) 1970–2005: Annual greenhouse emissions up 70% Past 50 years: Arctic temp rising almost twice as fast as the rest of the earth Melting of glaciers and floating sea ice Prolonged droughts: increasing Last 100 years: sea levels rose 10–20 cm 2007-Al Gore and the IPCC : Nobel Peace Prize “…the earth has a fever. And the fever is rising… We are what is wrong, and we must make it right” What natural and human-influenced factors could have an effect on temperature changes? Amplify (give positive feedback) Dampen (give negative feedback to)

14. Simplified Model of Some Major Processes That Interact to Determine Climate

15. Melting of Alaska’s Muir Glacier between 1948 and 2004

16. Comparison of Measured Temperature from 1860–2007 and Projected Changes

17. Is a Hotter Sun the Culprit? Energy output from the sun affects the earth’s temperature. Since 1975 Lower atmosphere (Troposphere) has warmed Stratosphere has cooled This is not what a hotter sun would do!! Atmosphere is heating from the bottom up…this indicates inputs at earth’s surface (from human activities) are the main cause.

18. Can the Oceans Save Us? Solubility of CO 2 in ocean water But, solubility of gases decreases as temp. of water increase Help moderate temperature-remove 25-30% CO 2 Warmer oceans CO 2 levels increasing acidity Effect on atmospheric levels of CO 2 Effect on coral reefs - ability of to make shells, could dissolve shells Antarctica’s Southern Ocean (largest CO 2 sink and the North Atlantic Ocean Decrease in CO 2 uptake Significance on global CO 2 levels Temperature, acidity, and the ability to absorb CO 2 from atmosphere are changing due to humans. This can accelerate global warming.

19. Uncertainty about the Effects of Cloud Cover on Global Warming Warmer temperatures increase evaporation and create more clouds Thick, light-colored low altitude clouds: decrease surface temperature Thin, cirrus clouds at high altitudes: increase surface temperature Effect of jet contrails on climate temperature – trails expand and turn into large cirrus clouds that release heat into the upper troposphere

20. Outdoor Air Pollution Can Temporarily Slow Global Warming Aerosols (suspended microscopic droplets of solid particles) and soot pollutants Most light-colored sulfate particles produced by fossil fuel combustion tend to reflect incoming light- also serve as condensation nuclei and form clouds (more cooling) BUT black carbon particulate matter emitted by diesel exhaust, burning forest and cooking fuels warms the atmosphere more than estimated

21. Scientists do not expect aerosols or soot pollutants to enhance or counteract projected global warming 1. Fall back to the earth or are washed out of the lower atmosphere within weeks, where as CO2 remains in the atmosphere for as long as 120 years! 2. Reduction: especially in developed countries Hmmm.. The decrease in some aerosols’ concentrations increase global warming!

22. Enhanced Global Warming Could Have Severe Consequences Why worry about it? How much and how fast Tipping point and irreversible climate change Worst-case scenarios Ecosystems collapsing Low-lying cities flooded Wildfires in forests Prolonged droughts: grasslands become dust bowls More destructive storms Glaciers shrinking; rivers drying up

23. Projected Effects of Global Warming and the Resulting Changes in Global Climate

24. 19-2 Severe Drought Is Increasing: The Browning of the Earth Drought=evaporation exceeds precipitation Accelerate global warming, lead to more drought Biodiversity will decrease NPP will decrease Dry climate ecosystems will increase Positive feedback-accelerate global warming and climate change= more drought

25. Ice and Snow Are Melting Why will global warming be worse in the polar regions? Light colored ice and snow=reflect solar energy-cool earth Melting exposed dark land=absorb more solar energy=polar are heat up Important climate role of floating sea ice-precipitation Mountain glaciers affected by Average snowfall Average warm temperatures Europe’s Alps Glaciers are disappearing South America Glaciers are disappearing Greenland Warmer temperatures

26. Sea Levels Are Rising 2007 IPPC-sea level will rise 18-59 cm this century Expansion of warm water Melting of land-based ice What about Greenland? 1-2 meters from 2050-2010 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

27. Areas of Florida to Flood If Average Sea Level Rises by One Meter

28. Permafrost Is Likely to Melt: Another Dangerous Scenario Carbon present as CH 4 in permafrost soils and lake bottoms 2004: Arctic Climate Impact Assessment 10–20% of the permafrost might melt this century Effect on global warming

29. Ocean Currents Are Changing but the Threat Is Unknown Melting glaciers, particularly in Greenland Increased rain in the North Atlantic Not thought to be an immediate problem on the ocean currents

30. Extreme Weather Will Increase in Some Areas Heat waves and droughts in some areas Prolonged rains and flooding in other areas Will storms get worse? More studies needed Hurricanes Katrina and Rita

31. Global Warming Is a Major Threat to Biodiversity Most susceptible ecosystems Coral reefs Polar seas Coastal wetland High-elevation mountaintops Alpine and arctic tundra What about Migratory animals Forests Which organisms could increase with global warming? Significance? Insects Fungi Microbes

32. Climate Change Will Shift Areas Where Crops Can Be Grown Regions of farming may shift Decrease in tropical and subtropical areas Increase in northern latitudes Less productivity; soil not as fertile Genetically engineered crops more tolerant to drought

33. Climate Change Will 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

34. 19-3 Dealing with Climate Change Is Difficult Global problem Long-lasting effects Long-term political problem Harmful and beneficial impacts of climate change unevenly spread Many proposed actions disrupt economies and lifestyles

35. What Are Our Options? Two approaches Drastically reduce the amount of greenhouse gas emissions Devise strategies to reduce the harmful effects of global warming Will we reach a political tipping point before we reach irreversible climate change tipping points?

36. Avoiding Catastrophe: We Can Reduce the Threat of Climate Change Input or prevention strategies Improve energy efficiency to reduce fossil fuel use Stop cutting down tropical forests Output strategy Capture and store CO 2 Socolow and Pacala Climate stabilization wedges Keep CO 2 emissions to 2007 levels by 2057 Brown: need to do more Cut CO 2 emissions by 80% by 2020 2008 book: Plan B 3.0: Mobilizing to Save Civilization

37. Output solutions Massive global tree planting; how many? Wangari Maathai Great Wall of Trees: China and Africa Plant fast-growing perennials on degraded land Capturing and storing CO 2

38. Fifteen Ways to Cut CO 2 Emissions

39. Some Output Methods for Removing CO 2 from the Atmosphere and Storing It

40. Should We Use Geo-Engineering Schemes to Help Slow Climate Change? CCS-Carbon capture and storage Injection of sulfate particles into the stratosphere Would it have a cooling effect? Would it accelerate O 3 depletion? Remove HCl from seawater Effects on ecology? Pump up nutrient-rich deep ocean water and cause algal blooms Re-ice the Arctic If any of these fixes fail, what about a rebound effect?

41. How Much Will It Cost to Slow Climate Change? Short-term costs lower Local and global economies may be boosted

42. Governments Can Help Reduce the Threat of Climate Change Strictly regulate CO 2 and CH 4 as pollutants Cap-and-trade approach Increase subsidies to encourage use of energy-efficient technology Technology transfer

43. We Can Move Beyond the Kyoto Protocol 2004: Stewart and Wiener New treaty needed Should be led by the U.S. Include the developing countries Cap-and-trade emissions program Set up 10 year goals

44. Some Governments Are Leading the Way Costa Rica: goal to be carbon neutral by 2030 Norway: aims to be carbon neutral by 2050 China and India must change energy habits U.S. cities and states taking initiatives to reduce carbon emissions

45. Some Companies and Schools Are Reducing Their Carbon Footprints Major global companies reducing greenhouse gas emissions Alcoa DuPont IBM Toyota GE Wal-Mart Fluorescent light bulbs Auxiliary power units on truck fleets Colleges and universities reducing greenhouse gas emissions Oberlin College, Ohio, U.S. 25 Colleges in Pennsylvania, U.S. Yale University, CT, U.S. What can you do?

46. We Can Prepare for the Harmful Effects of Climate Change Reduce greenhouse gas emissions as much as possible Move people from low-lying coastal areas Limit coastal building Remove hazardous material storage tanks away from the coast Genetically engineer crops more tolerant to drought Stockpile 1–5 years of key foods Waste less water Connect wildlife reserves with corridors

47. Our Use of Certain Chemicals Threatens the Ozone Layer Ozone Thinning Seasonal depletion in the stratosphere Antarctica and Arctic 1930: Midgely Discovered the first CFC 1984: Rowland and Molina CFCs were depleting O 3 Other ozone-depleting chemicals Global Average Total Ozone Values in the Stratosphere from 1979–2005

48. 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?

49. We Can Reverse Stratospheric Ozone Depletion Stop producing all ozone-depleting chemicals 60–100 years of recovery of the O 3 layer 1987: Montreal Protocol 1992: Copenhagen Protocol Ozone protocols: prevention is the key Substitutes for CFCs are available More are being developed HCFC-22 Substitute chemical May still be causing ozone depletion

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