Mr. Kling

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Ozone Depletion

• By
• Mr. Kling

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What is the Ozone Layer?

• A concentration of ozone molecules in the
  stratosphere.
• About 90 of the planets ozone is in the ozone
  layer.

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Why is the Ozone Layer Important?

• It filters the suns ultraviolet (UV) radiation.
• Overexposure to UV rays can lead to skin cancer,
  cataracts, and weakened immune systems.
• Increased UV exposure can also lead to reduced
  crop yields and disruptions in the marine food
  chain.

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Whats Damaging the Ozone Layer?

• Chlorofluorocarbons (CFCs) and ozone-depleting
  substances (ODS)
• They were used widely as propellants,
  refrigerants, insulating foams, and solvents.
• Methyl bromide (pesticide)
• Halons (used in fire extinguishers)
• Methyl chloroform (industrial solvent)

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Whats Being Done?

• In 1978, the U.S. banned the use of CFC
  propellants in spray cans.
• In the 1980s the Antarctic ozone hole
  appeared.
• It became evident that a stronger worldwide
  response was needed.

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The Montreal Protocol

• In 1987, many nations committed to a drastic
  reduction in the use of CFCs and other
  ozone-depleting substances.
• The treaty has since been amended to ban CFC
  production in developed nations after 1995.

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The Good News

• If we stop producing ozone-depleting substances,
  natural ozone reactions should return the ozone
  layer to normal levels by about 2050!