Ozone Layer Depletion

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Ozone Layer Depletion

• IB SL

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What Is It?

• The ozone layer is found in the upper
  stratosphere and its primary function is to
  filter ultraviolet short-wave radiation that
  comes from the sun.
• Ozone gas absorbs UV radiation.
• The 'hole' in the ozone layer was first noted in
  the 1980's, and is of concern as increased levels
  of UV radiation can leads to increased levels of
  skin cancer and eye cataracts.

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CFCs

• At first the ozone hole was only found over
  Antarctica, but it has been becoming larger at a
  rapid rate, and now affects parts of Chile and
  Australia.
• Although some natural repair occurs each year, it
  is not sufficient to limit the damage.
• The problem is worsened as CFC's are a primary
  cause of the damage and they remain in the
  stratosphere for up to 100 years.

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Causes Of Ozone Depletion
Source Impact
CFC's The increase in the size of the hole in the ozone layer is directly linked to increased production of CFC's since the 1950's in aerosols, plastic foam, fast food packaging and fridges. Chlorine is produced by CFC'S and reacts strongly with ozone in the stratosphere, breaking down the ozone layer.
Natural Causes Volcanic eruptions, as they release carbon monoxide and decrease nitrogen oxides in the atmosphere. Methane from rotting vegetation.
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Effects Of Ozone Depletion
Effect Explanation
Health Main concern is the increase in levels of UV radiation and the link to skin cancer. It is also connected to eye damage, where the cornea, retina and lens may be damaged. In severe cases, cataracts form.
Vegetation Inhibits photosynthesis in plants and increase likelihood of disease. Some evidence is contradictory.
Global Warming Large amounts of UV radiation can kill plankton found in oceans, which absorbs carbon dioxide, thus increasing the rate of global warming.
Other Effects Places stress on marine ecosystems reduces strength of wood and plastic products.
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Solutions To Ozone Depletion
Solution Detail
Education Pioneered in Australia, with the Sunsmart Campaign, advising people to cover up when out in the sunshine to reduce the damage caused by UV radiation.
Government legislation Australia in 1989 'Ozone Protection Act' banning production of import and manufacture of all CFC's. Restriction of aerosol use.
Removal Of CFC's Government legislation combines with development of alternatives to CFC's. Labelling of products as 'ozone friendly' to provide consumer choice. Pump action sprays instead of aerosols.
International Agreements Various, beginning with the Montreal Protocol in 1987, where measures have been taken to reduce CFC production. 1992 EU countries agree to halt CFC production by 1995.
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Activity

• Using P206-207 of Geography An Integrated
  Approach answer the questions below...
• What Is Ozone and what does it do?
• Why is Ozone dangerous to human health in the
  troposphere and why may there be a concern to
  Ozone being depleted in the stratosphere?
• What has been done to restrict damage to Ozone
  Depletion?