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Climate Change and Ozone Loss
Chapter 16
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Studying a Volcano to Understand Climate Change
Mt. Pinatubo, Philippines 1991 eruption Temporary world cooling Climate modeling Hansen’s model Fig. 16-1, p. 367
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Past Climate Changes Past global temperatures
Causes of climatic changes Glaciations and warmer interglacial periods Earth’s natural greenhouse effect (Fig. 5-5, p. 82)
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Average Global Temperature over the Past 900,000 Years
17 16 15 14 Average surface temperature (°C) 13 12 11 10 9 900 800 700 600 500 400 300 200 100 Present Thousands of years ago Fig. 16-2a, p. 369
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Temperature Changes Over Past 22,000 Years
Agriculture established 1 –1 Average temperature over past 10,000 years = 15°C (59°F) Temperature change (°C) – 2 End of last ice age – 3 – 4 – 5 20,000 10,000 2,000 1,000 200 100 Now Years ago Fig. 16-2b, p. 369
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Temperature Changes Over Past 1,000 Years
1.0 0.5 0.0 Temperature change (°C) –0.5 –1.0 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2101 Year Fig. 16-2c, p. 369
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Average Global Temperature Over Past 130 Years
15.0 14.8 14.6 14.4 Average surface temperature (°C) 14.2 14.0 13.8 13.6 1860 1880 1900 1920 1940 1960 1980 2000 2020 Year Fig. 16-2d, p. 369
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Ice Cores: Records of Past Climates
Fig. 16-3, p. 369
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Greenhouse Effect Fig. 5-5, p. 82
(b) The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared (IR) radiation, which rises into the lower atmosphere. Some of this IR radiation escapes into space as heat and some is absorbed by molecules of greenhouse gases and emitted as even longer wavelength IR radiation, which warms the lower atmosphere. (c) As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere. (a) Rays of sunlight penetrate the lower atmosphere and warm the earth's surface. Fig. 5-5, p. 82
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Major Greenhouse Gases
Water vapor Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) Table 16-1, p. 370
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Table 16-1, p. 370
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Atmospheric Carbon Dioxide and Global Temperatures
380 360 340 320 300 Concentration of carbon dioxide in the atmosphere (ppm) 280 Carbon dioxide 260 240 +2.5 220 200 Variation of temperature (˚C) from current level –2.5 180 –5.0 –7.5 Temperature change End of last ice age –10.0 160 120 80 40 Thousands of years before present Fig. 16-4, p. 370
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Climate Change and Human Activities
Human emissions of greenhouse gases US carbon dioxide emissions Troposphere warming 20th century warmest in 1000 years Average global temperatures rising 16 warmest years since 1980 Glaciers and floating sea ice melting Melting permafrost and release of more greenhouse gases Rising sea level
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Increases in Average Atmospheric Carbon Dioxide Since 1860
410 360 Parts per million 310 260 1800 1900 2000 2100 Year Carbon dioxide (CO2) Fig. 16-5a, p. 371
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Increases in Average Atmospheric Methane Since 1860
2.4 1.8 Parts per million 1.2 0.6 1900 2000 2100 1800 Year Methane (CH4) Fig. 16-5b, p. 371
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Increases in Average Atmospheric Nitrous Oxide Since 1860
320 310 300 Parts per million 290 260 1900 2000 2100 1800 Year Nitrous oxide (N2O) Fig. 16-5c, p. 371
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Shrinking Arctic Sea Ice (1979-2003)
Fig. 16-6, p. 372
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Scientific Consensus on Future Climate Change
Mathematical models Model data and assumptions Predictions of the models Models indicate most recent warming due to human activities Very likely Earth’s mean temperature will increase in 21st century
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Processes that Determine Average Temperature and Greenhouse Gas Content
Troposphere Cooling from increase CO2 removal by plants and soil organisms Warming from decrease CO2 emissions from land cleaning, fires, and decay Aerosols Heat and CO2 removal Heat and CO2 emissions Greenhouse gases Ice and snow cover Shallow ocean Land and soil biotoa Long-term storage Natural and human emissions Deep ocean Fig. 16-7, p. 372
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Measured Average Temperatures and Future Predictions
Fig. 16-8, p. 373
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Concerns about a Warmer Earth
Droughts Higher sea level and coastal flooding Disrupted ecology Economic and social costs Abrupt changes Severe storms Insects and infectious diseases
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Factors Affecting the Earth’s Temperature
Ability of oceans to store carbon dioxide Local global cooling is possible Effects of cloud cover Jet contrails Aerosols: volcanic eruptions and human activities Sulfate and black carbon aerosols Photosynthesis Methane emissions: methane hydrates
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Shallow and Deep Ocean Currents
Fig. 16-9, p. 374
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Benefits and Negative Impacts of Global Warming
Changes in water supply Decreased water quality Increased drought Increased flooding Snowpack reduction Melting of mountaintop glaciers Water Resources Shifts in food-growing areas Changes in crop yields Increased irrigation demands Increased pests, crop diseases, and weeds in warmer areas Agriculture Changes in forest composition and locations Disappearance of some forests, especially ones at high elevations Increased fires from drying Loss of wildlife habitat and species Forests Rising sea levels Flooding of low-lying islands and coastal cities Flooding of coastal estuaries, wetlands, and coral reefs Beach erosion Disruption of coastal fisheries Contamination of coastal aquifiers with salt water Sea Level and Coastal Areas Extinction of some plant and animal species Loss of habitats Disruption of aquatic life Biodiversity Decreased deaths from cold weather Increased deaths from heat and disease Disruption of food and water supplies Spread of tropical diseases to temperate areas Increased respiratory disease and pollen allergies Increased water pollution from coastal flooding Increased formation of photochemical smog Human Health Prolonged heat waves and droughts Increased flooding from more frequent, intense, and heavy rainfall in some areas Weather Extremes Increased deaths from heat and disruption of food supplies More environmental refugees Increased migration Human Population Fig , p. 376
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Possible Effects of Global Warming on Beech Trees
Future range Overlap Present range Fig , p. 377
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Rising Sea Levels Threaten Islands
Fig , p. 377
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Why Climate Change is a Difficult Problem
Complex causes Global problem: How can we all agree? Long-term problem Harmful and beneficial effects of climate change not spread evenly Can’t stop climate change, only slow rate and adapt Solutions are difficult and controversial
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Options to Deal with Climate Change
“Wait and see” strategy: we need more research “Act now” strategy “Act now with no regrets” strategy
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Solutions to Global Warming
Prevention Cleanup Cut fossil fuel use (especially coal) Remove CO2 from smokestack and vehicle emissions Shift from coal to natural gas Store (sequester) CO2 by planting trees Improve energy efficiency Shift to renewable energy resources Sequester CO2 deep underground Transfer energy efficiency and renewable energy technologies to developing countries Sequester CO2 in soil by using no-till cultivation and taking crop land out of production Reduce deforestation Sequester CO2 in the deep ocean Use more sustainable agriculture Repair leaky natural gas pipelines and facilities Limit urban sprawl Reduce poverty Use feeds that reduce CH4 emissions by belching cows Slow population growth Fig , p. 379
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Removing Carbon Dioxide from the Atmosphere
Tanker delivers CO2 from plant to rig Oil rig Coal power plant Tree plantation CO2 is pumped down from rig for deep ocean disposal Abandoned oil field Crop field Switchgrass CO2 is pumped down to reservoir through abandoned oil field Spent oil reservoir is used for CO2 deposit = CO2 deposit = CO2 pumping Fig , p. 380
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Government Roles in Reducing the Threat of Climate Change
Funding for carbon dioxide removal technologies Carbon taxes Energy taxes Decreasing other taxes Leveling the economic playing field Technology transfer Kyoto Protocol What other countries, cities and businesses are doing
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What Can You Do? What Can You Do? Reducing CO2 Emissions
Drive a fuel-efficient car, walk, bike, carpool, and use mass transit Use energy-efficient windows Use energy-efficient appliances and lights Heavily insulate your house and seal all drafts Reduce garbage by recycling and reuse Insulate hot water heater Use compact fluorescent bulbs Plant trees to shade your house during summer Set water heater no higher than 49°C (120°F) Wash laundry in warm or cold water Use low-flow shower head Fig , p. 382
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Preparing for Climate Changes
Connect wildlife reserves with corridors Move hazardous material storage tanks away from coast Expand existing wildlife reserves toward poles Stockpile 1- to 5-year supply of key foods Prohibit new construction on low-lying coastal areas or build houses on stilts Develop crops that need less water Waste less water Move people away from low-lying coastal areas Fig , p. 382
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Ozone Depletion in the Stratosphere
Location and purpose of the ozone layer Seasonal and long-term depletion of ozone Causes: chlorofluorocarbons (CFCs) and other chemicals How CFCs destroy the ozone layer Rowland and Molina’s research
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Former Uses of CFCs Coolants in air conditioners and refrigerators
Propellants in aerosol cans Cleaning solutions for electronic parts Fumigants Bubbles in plastic packing foam
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Ozone Thinning Seasonal More severe over Antarctica than the Arctic
Consequences Models
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Consequences of Ozone Loss
Natural Capital Degradation Effects of Ozone Depletion Human Health Worse sunburn More eye cataracts More skin cancers Immune system suppression Food and Forests Reduced yields for some crops Reduced seafood supplies from reduced phytoplankton Decreased forest productivity for UV-sensitive tree species Wildlife Increased eye cataracts in some species Decreased population of aquatic species sensitive to UV radiation Reduced population of surface phytoplankton Disrupted aquatic food webs from reduced phytoplankton Air Pollution and Materials Increased acid deposition Increased photochemical smog Degradation of outdoor paints and plastics Global Warming Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases Fig , p. 384
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Squamous Cell Carcinoma
Skin Cancers Ultraviolet A Ultraviolet B Thin layer of dead cells Hair Epidermis Squamous cells Basal layer Sweat gland Melanocyte cells Dermis Basal cell Blood vessels Squamous Cell Carcinoma Basal Cell Carcinoma Melanoma Fig a, p. 385
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Squamous Cell Carcinoma
Skin Cancers DO NOT POST TO INTERNET DO NOT POST TO INTERNET Squamous Cell Carcinoma Melanoma DO NOT POST TO INTERNET Basal Cell Carcinoma Fig bcd, p. 385
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Reducing Exposure to Ultraviolet Radiation
What Can You Do? Reducing Exposure to UV-Radiation Stay out of the sun, especially between 10 A.M. and 3 P.M. Do not use tanning parlors or sunlamps. When in the sun, wear protective clothing and sun– glasses that protect against UV-A and UV-B radiation. Be aware that overcast skies do not protect you. Do not expose yourself to the sun if you are taking antibiotics or birth control pills. Use a sunscreen with a protection factor of 15 or 25 if you have light skin. Examine your skin and scalp at least once a month for moles or warts that change in size, shape, or color or sores that keep oozing, bleeding, and crusting over. If you observe any of these signs, consult a doctor immediately. Fig , p. 386
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Protecting the Ozone Layer
Slow recovery of the ozone layer Montreal Protocol: Reducing CFC emissions Copenhagen Protocol International cooperation Individuals Matter, p. 386: Ray Turner and His Refrigerator
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