1. The Ozone Hole

2. The Ozone Layer Stratospheric ozone Block 95% harmful UV radiation http://svs.gsfc.nasa.gov/goto?824

3. ODC: Ozone Depleting Chemicals CFC’s: Chlorofluorocarbons –Stable, odorless, nonflammable, nontoxic, noncorrosive –Coolants, propellants, cleaners, fumigants, insulation Halons (bromine, fluorine) –Fire extinguishers –Solvents –Fumigants

4. Rowland and Molina: Groundbreaking Study 1974 CFC’s remain in troposphere (65 – 385 years) CFC’s are heavier than air, but are carried to the stratosphere by convection and turbulence CFC molecules break down with high energy input from UV radiation Chlorine molecules break apart ozone http://svs.gsfc.nasa.gov/goto?825

5. The Ozone Hole: Discovered 1984 Ozone thinning, NOT ozone “hole” Occurs over Antarctica during spring (Aug – Nov) http://svs.gsfc.nasa.gov/goto?3303

6. Impacts of Ozone Depletion Human Health –Skin cancer, sunburns, eye cataracts Reduced primary productivity in the ocean (kills plankton, algae) –Impacts on food web and CO 2 Potential damage to food crops Degradation of materials (paints and plastics)

7. Management: The Montreal Protocol, 1987 International agreement Eliminate CFC production (goal) –By 1995 in developed nations –By 2000 in developing nations Assessment of Effectiveness: –ODC’s will return to pre-1980 levels by 2050 –Ozone “hole” is shrinking!!!