1. Ozone Depletion in the Stratosphere

2. Overview of Ozone Depletion

3. 2000 – hole reached 11.3 million square miles
Stratospheric ozone thinning first observed –1985
- scientistis working in Antarctica
- Article in Nature reported the results
– Ozone levels over Antactic had thinned by 50 – 98%!
2000 – hole reached 11.3 million square miles

5. Stratospheric ozone thinning over the Arctic

6. 1995 – First Nobel Prize in Env. Sci
1995 – First Nobel Prize in Env. Sci. awarded for connecting the ozone hole to CFC.
1996 – CFCs were phased out in the U.S.
October 2007 

7. Causes of Ozone Depletion
Chlorine or Bromine Compounds
Chlorofluorocarbons (CFC)
- nonpoisonous, nonflammable, & non-corrosive.
- Propellants for aerosol cans
- Coolants in A.C. & refigerators
(Ex: Freon)
- Foam-blowers (EX: styrofoam)
- Industrial solvents
- Fire retardants

9. Return of sunlight to polar region Circumpolar vortex
Thinning is worst between September & November (spring in S. Hemisphere) for 2 reasons…
Return of sunlight to polar region
Circumpolar vortex

11. Effects of Ozone Depletion
High UV Exposure leads to
Eye cataracts
Skin cancer
Weakened Immunity
Disruption of Ecosystems
Antarctic food web
DNA mutations in fish
Damage to crops & forest
Decline in amphibian populations

12. Facilitating the Recovery of the Ozone Layer
Montreal Protocol – international agreement to reduce CFCs by 50% (1998)
- modified to have stricter regulations
CFC substitutes
- Hydrofluorocarbons (HFCs)  does not thin ozone, but is a greenhouse gas
- Hydrochlorofluorocarbons (HCFCs)
CFC leaking out of old refrigerators & A.C.
CFC smuggling – black market