Ozone layer recovering thanks to Montreal

• zone gas in stratosphere prevents 99.5% entry of UV radiation (255nm) on earth.
• Chlorofluorocarbons / freons: non-reactive, non-flammable, non-toxic. Used in Refrigerators, spray cans, insulation foam and propellant.
• Once they’re released in atmosphere, they reach stratosphere=> react with UV=> release Chlorine free radicals => Ozone broken.
• 1980s: Scientists realized Chlorofluorocarbons (CFCs) reach had damaged Ozone layer above Antarctica. Result?
  • Skin cancer, Cataract, Sunburns
  • Phytoplanktons die=> fish population declines.
  • Soil Moisutre content declines, plant proteins are mutated=> plant growth affected.
  • Fibers and Wall paints fade faster.
• Late 80s: Montreal Protocol signed, to cut down use of
  • chlorofluorocarbons (CFCs) / freons
  • Halons in fire-extinguishers
• 2014: CFC has declined by 90%, Ozone layer showing signs of recovery- as per United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO).
• This will also prevented 2 million skin cancer cases per year.
• 2050: Ozone Layer will recover near mid-latitudes
• 2075: Ozone layer will recover near Antarctic.

Challenges:

1. CFCs are replaced with HFCs (Hydroflurocarbons). Although HFCs don’t deplete Ozone layer but they’re greenhouse gases, hence contribute to global warming.
2. Researchers found Carbon tetrachloride increased in atmosphere. This is a banned ozone-depleting carcinogenic solvent.
3. Meaning, some companies in the third world countries are still using it illegally, as a cheaper alternative to HFCs.