Key Points: Ozone Hole
¥CFCs stay in atmosphere for ~100 years
One
freed chlorine atom destroys thousands of O3 molecules
before leaving stratosphere¥Montreal Protocol mandated total phase out of ozone depleting substances by 2000.
¥Even with a complete phase out, O3 levels
Would
not increase for another 10-20 yearsWould
not completely recover for ~100 years