Note4Students

From UPSC perspective, the following things are important :

Prelims level : Ozone hole

Mains level : Ozone depletion and its impact on climate change

• During September and October, the ozone hole over the Antarctic has been the smallest observed since 1982.

Shrinking ozone hole

• The annual ozone hole reached its peak extent of 16. 4 million sq km on September 8, then shrank to less than 10 million sq km for the remainder of September and October, satellite measurements show.
• NASA has described it as great news for the Southern Hemisphere.

Ozone hole

• Ozone, made up of three oxygen atoms, occurs naturally in small amounts.
• Roughly 10 km to 40 km up in the atmosphere (the layer called the stratosphere), the ozone layer is a sunscreen, shielding Earth from harmful ultraviolet radiation.
• On the other hand, close to the surface, ozone created as a byproduct of pollution can trigger health problems such as asthma and bronchitis.
• Manufactured chemicals deplete the ozone layer. Each spring over Antarctica (it is now spring there), atmospheric ozone is destroyed by chemical processes.
• This creates the ozone hole, which occurs because of special meteorological and chemical conditions that exist in that region.

Why it is smallest this year?

• There have been abnormal weather patterns in the atmosphere over Antarctica.
• In warmer temperatures like this year, fewer polar stratospheric clouds form and they don’t persist as long, limiting the ozone-depletion process.