Study finds Climate variability may explain annual spike in ozone-destroying gas

March 22, 2022
Posted by: OptimizeIAS Team
Category: DPN Topics

Study finds Climate variability may explain annual spike in ozone-destroying gas

Subject: Environment

Section: Climate change

Context: Forest fires fueled by the El Niño Southern Oscillation (ENSO) phenomenon might be responsible for the short-term spikes in methyl bromide, a known destroyer of the ozone layer

El Niño–Southern Oscillation:

El Niño–Southern Oscillation(ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.
The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.
Southern Oscillation, in oceanography and climatology, is a coherent inter-annual fluctuation of atmospheric pressure over the tropical Indo-Pacific region.
The Southern Oscillationis the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there.
El Nino and Southern Oscillation coincide most of the times hence their combination is called ENSO – El Nino Southern Oscillation.

Methyl Bromide:

Methyl bromide is an odourless, colourless gas that has both natural and industrial sources.
It naturally enters the atmosphere from oceans and forest fires. Human activities can release the gas too. About 50-95 per cent of the substance eventually makes it back into the atmosphere, according to the United States Environment Protection Agency.
It is used to control a wide variety of pests in agriculture and shipping, including fungi, weeds, insects, nematodes (or roundworms), and rodents.
And can be used as quarantine fumigant at ports.
Methyl bromide is also an ozone-depleting substance.
- India has signed and ratified the Montreal Protocol, and is committed to phasing out methyl bromide and other ozone-depleting substances (ODS) by 2015.

Ozone:

Ozone occurs in two layers of the atmosphere.
The layer closest to the Earth’s surface is the troposphere. Here, ground level or “bad” ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation.
The stratosphere or “good” ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun’s harmful ultraviolet (UV) rays.
- “Good” ozone is gradually being destroyed by man-made chemicals referred to as ozone-depleting substances (ODS), including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, and methyl chloroform.

Montreal Protocol:

Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
It was agreed on 16 September 1987, and entered into force on 1 January 1989.
Since then, it has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali)
As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070.