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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 14th Edition Chapter 21

  2. Key Concepts • Changes in Earth’s climate over time • Factors affecting climate • Possible effects of global warming • Adapting to climate change • Human impacts on the ozone layer • Protecting and restoring the ozone layer

  3. Past Climate Changes Average temperature over 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

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

  5. 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

  6. Recent trends in global temperatures 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

  7. IPCC • 1988 UN and the World Meteorological Organization established the (IPCC) Intergovernmental Panel on Climate Change to document past climate change and project future climate change. • A network of over 2,000 leading climate experts from 70 nations.

  8. Table 21-1Page 464 Table 21-1 Major Greenhouse Gases from Human Activities Greenhouse Gas Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) Chlorofluorocarbons (CFCs)* Hydrochloro- fluorocarbons (HCFCs) Hydrofluorocarbons (HFCs) Halons Carbon tetrachloride Human Sources Fossil fuel burning, especially coal (70–75%), deforestation, and plant burning Rice paddies, guts of cattle and termites, landfills, coal production, coal seams, and natural gas leaks from oil and gas production and pipelines Fossil fuel burning, fertilizers, livestock wastes, and nylon production Air conditioners, refrigerators, plastic foams Air conditioners, refrigerators, plastic foams Air conditioners, refrigerators, plastic foams Fire extinguishers Cleaning solvent Average Time in the Troposphere 100–120 years 12–18 years 114–120 years 11–20 years (65–110 years in stratosphere) 9–390 15–390 65 42 Relative Warming Potential (compared to CO2) 1 23 296 900–8,300 470–2,000 130–12,700 5,500 1,400

  9. The Greenhouse Effect Fig. 6-14 p. 110

  10. Climate Change and Human Activities • Increased use of fossil fuels • Deforestation • Global warming • Melting icecaps and glaciers • Rising sea level

  11. Global Warming • Svante Arrhenius first speculated in 19th century • Current Causes • Deforestation • Greenhouse Gas Levels • Burning of Fossil Fuels • Main villain is currently Carbon Dioxide (CO2)

  12. Deforestation

  13. Deforestation - US • About one half of the forests that covered the Earth are gone • Since 1600, 90% of the U.S. forests have been cleared away

  14. Deforestation - Rainforests One football field of rainforest is lost every 1.4 seconds

  15. Results of Deforestation • Loss of trees’ ability to remove CO2 • Decaying trees release CO2 and methane • 25% of global GHG emissions • Fallen trees are often burnt which releases CO2 • Accounts for 20% of global CO2 emissions • Deforestation the largest source of emissions in developing countries

  16. Greenhouse Effect

  17. Greenhouse Effect • Certain gases in the Earth’s atmosphere trap energy from the sun • carbon dioxide – water vapor • methane – nitrous oxide • Without these gases, the Earth’s average temperature would be about 60ºF colder • These gases are Greenhouse Gases

  18. Global Warming

  19. Evidence • CO2 and Temperature

  20. Five Warmest Years on Record • 2005 • 1998 • 2002 • 2003 • 2006 Since 1980, the Earth has experienced 19 of its 20 hottest years on record

  21. Evidence • CO2 and Temperature • Glaciers

  22. Portage Glacier- near Anchorage Alaska- 1950/2001

  23. Rhone glacier in the Kanton of Valais, Switzerland 1859 / 2001

  24. Grinnell glacier, Glacier National Park, USA 1911 / 2000

  25. Glacier Ururashraju, at about 15,000 feet in Cordillera Blanca of Peru 1986 / 1999

  26. 2004 2004

  27. Glaciers • Have been shrinking throughout the 20th Century • Loss of glaciers in South America and Asia glaciers is particularly rapid and will threaten the water supplies of millions of people

  28. Evidence • CO2 and Temperature • Glaciers • Polar Ice • Arctic • Antarctic • Greenland

  29. Arctic Ice

  30. Perennial ice may be 10 or more feet thick New ice is only one to seven feet thick Since 1970  10% loss of ice cover per decade Arctic Ice

  31. Albedo Effect

  32. Albedo, or reflectivity Fig. 21-17 p. 480

  33. NASA Sees Rapid Changes in Arctic Sea Ice NEWS RELEASE: September 13, 2006 • From 1970 until 2000 there was a 10 percent decrease in Arctic perennial sea ice every decade • Between 2004 and 2005 the ice shrunk abruptly by 14 percent

  34. Permafrost