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.