OZONE DEPLETIONOZONE DEPLETION

A Significant Environmental IssueA Significant Environmental Issue

What is the Ozone Layer?What is the Ozone Layer?

An important layer of OAn important layer of O33

Located in the stratosphereLocated in the stratosphere Absorbs incoming ultraviolet rays from the sunAbsorbs incoming ultraviolet rays from the sun Acts as a sunscreen for the earthActs as a sunscreen for the earth

What is Ozone Depletion?What is Ozone Depletion?

Thinning and breakdown of the ozone layerThinning and breakdown of the ozone layer

Causes of Ozone DepletionCauses of Ozone Depletion

Human (75 - 85%):Human (75 - 85%):– CFCs, HCFCs, carbon tetrachloride, haloCFCs, HCFCs, carbon tetrachloride, halo

nsns– Methyl bromide, methyl chloroform Methyl bromide, methyl chloroform

Nature (15 - 25%):Nature (15 - 25%):– Methyl chloride, HCl Methyl chloride, HCl

Impacts/EffectsImpacts/Effects

AtmosphereAtmosphere– 1% ozone depleted = 2% UV-B reaching 1% ozone depleted = 2% UV-B reaching

earth’s surfaceearth’s surface

– Climatic changes throughout the worldClimatic changes throughout the world

Impacts/EffectsImpacts/Effects

BiosphereBiosphere– Life cycle of plants will changeLife cycle of plants will change– Harmful to planktonsHarmful to planktons– Damage to lens, cornea, and retinaDamage to lens, cornea, and retina– Causes skin cancerCauses skin cancer– 60 million Americans 60 million Americans

1 million will die1 million will dieskin cancer by 2075skin cancer by 2075

Possible SolutionsPossible Solutions

19871987– 30 countries signed the Montreal Protocol 30 countries signed the Montreal Protocol

19891989– Montreal Protocol finally takes effectMontreal Protocol finally takes effect

Development of replacement for CFCsDevelopment of replacement for CFCs Knowledge of current situation to everyoneKnowledge of current situation to everyone Recycling old refrigeratorsRecycling old refrigerators

Ozone hole over AntarcticOzone hole over Antarctic

Composition: NComposition: Nitric acid and icitric acid and ice crystalse crystals

ReferencesReferences

Warburton, P. (1999) Atmospheric Processes and Human Influence, Hong Kong: HarperCollins Publishers.

Fisher, M. (1992) The Ozone Layer, New York: Chelsea House Publishers.

Morgan, Sally. The Ozone Hole. Danbury, CT: Franklin Watts, 1999.