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Chapter 6 Humans in the Biosphere

Chapter 6 Humans in the Biosphere. Section 6-4 Charting a Course for the Future. Charting A Course. Key Concept: As We Enter The 21 st Century, Many Biologists Are Concerned About The Biological Effects Of Two Types Of Global Change: The thinning, or depletion, of the ozone layer

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Chapter 6 Humans in the Biosphere

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  1. Chapter 6Humans in the Biosphere Section 6-4 Charting a Course for the Future

  2. Charting A Course Key Concept: As We Enter The 21st Century, Many Biologists Are Concerned About The Biological Effects Of Two Types Of Global Change: • The thinning, or depletion, of the ozone layer • Global Warming

  3. Oxygen Gas

  4. Ozone Molecule

  5. Ozone Depletion • Ozone layer • 20/50 km above earth (12 – 31 miles) • Oxygen = O2 • Ozone = O3 • Ozone at ground level is a pollutant • In the upper atmosphere it is VERY important

  6. Ozone Layer • Absorbs Ultraviolet Radiation (UV) • UV Radiation Can Cause: • Sunburn • Cancer • Eye Damage • Cataracts • Decreased Resistance To Disease • Destruction of Plants & phytoplankton

  7. Ozone The Universal Sunscreen

  8. Ozone Hole - South Pole

  9. Ozone Depletion • Discovered in 1970’s over Antarctica • Hole is growing larger • Now occurring over the Arctic • 1995 • grew large enough to expose U.S.

  10. Ozone Hole Caused By CFC’s Chlorofluorocarbons CFC’s act as a catalyst CFC’s have a long half-life 2O3 + CFC’s 3O2

  11. Where Do CFC’s Originate? • CFC’s found in • aerosol cans • coolants used in • refrigerators • freezers • automobile air conditioning

  12. Montreal Protocol 1987 46 Nations Agreed to end use of CFC’s by 2000

  13. Change In Atmospheric Chlorine

  14. Global Warming

  15. Global Warming

  16. Global Warming

  17. Climate Change • Any Climate Change will have profound effects on the Biosphere. • Over past 120 years average global temperature has increased 0.5 degrees Celsius (0.9 degrees F) • Rise between 1980-2000 fastest in over 100 years.

  18. Climate Change • Ice caps are melting • Artic Sea Ice may be gone in 50 years

  19. Why is it happening? • CO2 Methane (Greenhouse Gases) • Burning Fossil Fuels, Forests • Project Increase of 1 – 2 degrees Celsius by 2050 • BUT, Some scientists wonder if this is not a natural cycle.

  20. Global Warming Effects • Polar Ice Melt • Rising Sea Levels • Increase in number & severity of storms • North American droughts • Shifts in plant & animal species distribution

  21. Ways to Help the Biosphere • Decrease energy consumption • Insulate Homes • Energy Efficient Appliances • High Mileage Cars • High Efficiency Energy Production • Alternate Fuel Sources • Fuel Cells • Wind

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