1. The largest hole in the earth’s ozone layer over the Arctic has closed, confirm scientists

What is Ozone? Why is it important?

What causes the ozone hole?

Why this year’s Arctic ozone hole was massive?

At these projected rates, when does the ozone hole recover completely?

UPSC Can list these Questions under

GS paper 3 ( Environmental impact Assessment )

What is the context about?

  • The largest hole in the Ozone layer above the Arctic caused due to the unusual atmospheric conditions has closed, as per reports.
  • The hole was first identified by scientists in March this year.
  • The Copernicus Climate Change Service (C3S) and Copernicus Atmosphere Monitoring Service (CAMS) by the European Centre for Medium-Range Weather Forecasts (ECMWF) confirmed the development.

What is Ozone? Why is it important?

  • Ozone (chemically, a molecule of three oxygen atoms) is found mainly in the upper atmosphere, an area called stratosphere, between 10 and 50 km from the earth’s surface.
  • Though it is talked of as a layer, ozone is present in the atmosphere in rather low concentrations.
  • But they perform a very important function. By absorbing the harmful ultraviolet radiations from the sun, the ozone molecules eliminate a big threat to life forms on earth. UV rays can cause skin cancer and other diseases and deformities, in plants and animals.

What causes the ozone hole?

  • The ‘ozone hole’ is not really a hole. It is a region in the stratosphere, directly above Antarctica, where the concentration of ozone has been measured to become extremely low in certain months.
  • Depletion is not limited to that area and has happened in other regions of the stratosphere as well.
  • But a set of special meteorological and chemical conditions that arise over the Antarctica in the months of September, October and November make the problem much more acute there.

Why this year’s Arctic ozone hole was massive?

  • NASA said that this could have happened because of an extraordinarily high temperatures in the stratosphere this year, rather than the ongoing human efforts to contain the ozone depletion.
  • Scientists have reported that temperatures in some areas of the stratosphere — usually over 100 degrees below zero — were 30° to 40°C higher than normal in September this year.
  • As per a European Space Agency report, cold temperatures (below -80°C), sunlight, wind fields and substances such as chlorofluorocarbons (CFCs) were responsible for the degradation of the Arctic ozone layer.

At these projected rates, when does the ozone hole recover completely?

  • As per the Scientific Assessment of Ozone Depletion data of 2018, the ozone layer in parts of the stratosphere has recovered at a rate of 1-3 per cent per decade since 2000.
  • “At these projected rates, the Northern Hemisphere and mid-latitude ozone is predicted to recover by around 2030, followed by the Southern Hemisphere around 2050, and polar regions by 2060,” the report said.