OZONE HOLE - ENVIRONMENT

News: Ozone hole, filling up now: What this means for climate action

 

What's in the news?

       The scientific assessment has suggested the ozone ‘hole’, once considered to be the gravest danger to planetary life, is now expected to be completely repaired by 2066.

       In fact, it is only the ozone layer over Antarctica - where the hole is the most prominent, which will take a long time to heal completely.

       Over the rest of the world, the ozone layer is expected to be back to where it was in 1980 by 2040 itself, an UN-backed scientific panel has reported.

 

Key takeaways:

       The recovery of the ozone layer has been made possible by the successful elimination of some harmful industrial chemicals, together referred to as Ozone Depleting Substances or ODSs, through the implementation of the 1989 Montreal Protocol.

       The assessment has reported that nearly 99 percent of the substances banned by the Montreal Protocol have now been eliminated from use, resulting in a slow but definite recovery of the ozone layer.

 

Significance of Ozone Layer:

       Ozone (chemically, a molecule having three Oxygen atoms, or O3) is found mainly in the upper atmosphere, an area called stratosphere, between 10 and 50 km from the Earth’s surface.

       It is critical for planetary life, since it absorbs ultraviolet rays coming from the Sun.

       UV rays are known to cause skin cancer and many other diseases and deformities in plants and animals.

 

Ozone Depletion:

       Ozone hole in the ozone layer is actually just a reduction in concentration of the ozone molecules. Even in the normal state, ozone is present in extremely low concentrations in the stratosphere.

       Where the ‘layer’ is supposed to be the thickest, there are no more than a few molecules of ozone for every million air molecules.

       The depletion of the ozone layer, first noticed in the early 1980s, used to be the biggest environmental threat before climate change came along.

       This drop was much more pronounced over the South Pole, which was later linked to the unique meteorological conditions such as temperature, pressure, wind speed and direction - that prevailed over Antarctica.

       The ozone hole over Antarctica is the biggest during the months of September, October, and November.

 

Causes for Ozone Depletion:

       The chief cause of ozone depletion was the use of a class of industrial chemicals that contained chlorine, bromine or fluorine.

       The most common of these were the chlorofluorocarbons, or CFCs, that were used extensively in the air conditioner, refrigeration, paints, and furniture industries.

 

Montreal Protocol:

       The Montreal Protocol on Substances that deplete the Ozone layer is the landmark multilateral environmental agreement that regulates the production and consumption of nearly 100 man-made chemicals referred to as ozone depleting substances (ODS).

       Adopted on 15 September 1987, the Protocol is to date the only UN treaty ever that has been ratified by every country on Earth – all 198 UN Member States.

       India has successfully met the phase out targets of all the Ozone Depleting Substances as per the Montreal Protocol Schedule.

 

Kigali Amendment:

       The Montreal Protocol was amended in 2016 to extend its mandate over hydrofluorocarbons, or HFCs, that have replaced the CFCs in industrial use.

       HFCs do not cause much damage to the ozone layer, but are very powerful greenhouse gases.

       The Kigali Amendment to the Montreal Protocol seeks to eliminate 80-90 per cent of the HFCs currently in use by the year 2050 to prevent another 0.3 to 0.5 degree Celsius of global warming by the turn of the century.