Emerging risks

Even as the world gets set to eliminate substances threatening the ozone layer, climate change and space advancement pose new challenges.

IN JUNE this year, the world's 35-year-long effort to restore and preserve its ozone layer got a major boost, when researchers confirmed dropping levels of chemicals which deplete this shield that protects us from the sun's ultraviolet radiation.

These chemicals, hydrochlorofluorocarbons (HCFCS), are part of a set of 100-odd substances which have elements like chlorine and bromine that destroy ozone molecules.

Their release thus depletes the ozone layer 15 to 35 km above the Earth's surface. The ozone layer is the thinnest over the poles, especially in the Antarctic stratosphere, where the depletion is known as the "ozone hole".

But the June study, led by a scientist from Bristol University, UK and published in Nature Climate Change, indicated signs of ozone healing by noting that for the first time since the 1970s, the impact of HCFCS on the Earth's energy balance and the amount of chlorine from these gases in the atmosphere have decreased after reaching a peak in 2021.

This is five years ahead of the projected peak year of 2026. More encouraging news came the same month, with a study led by researchers from the Indian Institute of Technology (IIT), Kharagpur, refuting claims made in 2022 of a "severe" ozone hole in the tropical stratosphere. Analysing ground-based and satellite data, the study says, "Current understanding and observational evidence do not provide any support for the possibility of an ozone hole occurring outside Antarctica today."