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Climate Change and Ozone Loss

Climate Change and Ozone Loss. G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 18. Past Global Temperatures. Temperature change over past 22,000 years. 2. Agriculture established. 1. 0. -1. End of last ice age. Temperature change (°C). -2. -3.

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Climate Change and Ozone Loss

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  1. Climate Change and Ozone Loss G. Tyler Miller’s Living in the Environment 13th Edition Chapter 18

  2. Past Global Temperatures Temperature change over past 22,000 years 2 Agriculture established 1 0 -1 End of last ice age Temperature change (°C) -2 -3 Average temperature over past 10,000 years = 15°C (59°F) -4 -5 20,000 10,000 2,000 1,000 200 100 Now Years ago

  3. Recent Trends in Global Temperature Temperature change 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

  4. Recent Trends in Global Temperature Average 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

  5. Climate Change • Past globaltemperatures • Recent trends in global temperatures

  6. Radioisotopes in rocks and fossils Plankton and radioisotopes in ocean sediments Pollen from lake bottoms Ice cores from ancient glaciers Tree rings Radioisotopes in corals Historical records Temperature measurements How do we know what past temperature changes were?

  7. The Natural Greenhouse Effect(tropospheric heating effect)

  8. Greenhouse Gases in the Largest Concentration Water Vapor Carbon Dioxide

  9. Hydrologic (Water) Cycle

  10. The Carbon Cycle (Terrestrial)

  11. The Carbon Cycle (Aquatic)

  12. Climate Change and Human Activities Increased use of fossil fuels (CO2 ,CH4) Deforestation (CO2 ,N2O) Cultivation of Rice Patties (N2O) Global warming = Enhanced greenhouse effect Melting icecaps and glaciers Coral reef bleaching Other

  13. Factors Affecting Changes in Earth’s Average Temperature • Changes in solar output • Changes in Earth’s albedo • Moderating effect of oceans • Clouds and water vapor • Air pollution

  14. Six Degrees Could Change the World

  15. Some Possible Effects of a Warmer World Water Distribution Plant and Animal Biodiversity Loss Ocean Currents and Sea Levels Extreme Weather Human Population and Health Agriculture and Forests

  16. Some Possible Effects of a Warmer World Fig. 18-16 p. 461

  17. Removing CO2 From the Atmosphere Tree plantation Coal power plant Tanker delivers CO2 from plant to rig Oil rig CO2 is pumped down from rig for Deep ocean disposal Abandoned oil field CO2 is pumped down to reservoir through abandoned oil field Crop field Switchgrass field Spent oil reservoir is used for CO2 deposit Fig. 18-21 p. 467 = CO2 deposit = CO2 pumping

  18. Reducing Greenhouse Gas Emissions Rio Earth Summit (1992) 106 nations Scientific uncertainty must not be used as justification to do nothing. Industrialized nations must take lead in slowing down rate and degree of global warming. Developed countries voluntarily committed to reducing CO2 to 1990 levels by the year 2000

  19. Reducing Greenhouse Gas Emissions Kyoto Treaty (1997) 161 nations Required 38 developed countries to cut greenhouse emissions 5.2% below 1990 levels by 2012.. Did not require developing countries to make cuts. Allowed emission trading among participating countries. Was not ratified until 2005 Approximately 180 participating countries.

  20. United States did not ratify Kyoto Treaty - Treaty fails to require emission reductions from developing countries (81% of world’s population) Economists predicted it would have devastating impact on U.S. economy and workers

  21. Some U.S. CO2 Reductions Concern among leaders of some U.S. companies. Several major companies have established targets to reduce greenhouse gas emissions by 10-65% from 1990 levels by 2010. Automobile companies investing in hybrid gas-electric and fuel cell engines. Local governments established programs to reduce greenhouse gas emissions. California first state to require a reduction in CO2 emissions from motor vehicles beginning in 2009.

  22. A growing number of analysts suggest we should begin to prepare for the possible effects of long-term atmospheric warming and climate change!

  23. Ozone Depletion in the Stratosphere(the other story)

  24. Photochemical ozone 40 25 35 20 Stratosphere 30 Benefical Ozone 25 Stratospheric ozone 15 Altitude (kilometers) Altitude (miles) 20 10 15 10 5 Troposphere Harmful Ozone 5 0 0 0 5 10 15 20 Ozone concentration (ppm)

  25. Ozone Depletion in the Stratosphere Importance of Ozone Essential for terrestrial life Reduces sunburn Prevents tropospheric ozone

  26. Ozone Depletion in the Stratosphere Fig. 18-26 p. 473

  27. Sun Cl Cl C Cl F UV radiation O O O O O Cl Cl Cl Cl Cl O O O O O Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2. Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2. The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2). The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). Stepped Art Fig. 20-18, p. 486

  28. Ozone Depleting Chemicals • Chlorofluorocarbons (CFCs) • Methyl bromide (fumigant) • Halons (fire extinguishers) • Carbon tetrachloride (solvent) • Methyl chloroform (cleaning solvent and propellant) • N-propyl bromide (solvent)

  29. OZONE DEPLETION IN THE STRATOSPHERE During four months of each year up to half of the ozone in the stratosphere over Antarctica and a smaller amount over the Artic is depleted.

  30. Reasons for Concern • Increased incidence and severity of sunburn • Increase in eye cataracts • Increased incidence of skin cancer • Immune system suppression • Increase in acid deposition • Lower crop yields and decline in productivity

  31. This long-wavelength (low-energy) form of UV radiation causes aging of the skin, tanning, and sometimes sunburn. It penetrates deeply and may contribute to skin cancer. This shorter-wavelength (high-energy) form of UV radiation causes sunburn, premature aging, and wrinkling. It is largely responsible for basal and squamous cell carcinomas and plays a role in malignant melanoma. Ultraviolet A Ultraviolet B Thin layer of dead cells Hair Squamous cells Epidermis Basal layer Sweat gland Melanocyte cells Dermis Basalcell Blood vessels Squamous Cell Carcinoma Melanoma Basal Cell Carcinoma Fig. 20-22, p. 489

  32. Solutions: Protecting the Ozone Layer • Use CFC substitutes • Montreal Protocol (1987) • only CFCs • Copenhagen Protocol (1992) • all ODCs

  33. Characteristics of Global Warming and Ozone Depletion Global Warming CO2, CH4, NOx (greenhouse gases) Absorbs infrared (IR) radiation Raising the earth’s surface temperature Decrease burning of fossil fuels Ozone Depletion O3, O2, and CFCs Absorbs ultraviolet (UV) radiation Decreasing O3 concentration in the stratosphere Eliminate CFCs

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