ABOARD XUELONG 2, Dec. 29, 2019 (Xinhua) -- Photo taken on Dec. 11, 2019 shows an iceberg in the Cosmonaut Sea. During China's 36th Antarctic expedition, China's first domestically made polar icebreaker Xuelong 2 has to overcome various difficulties including colliding with icebergs. (Xinhua/Liu Shiping/IANS)

Ozone-depleting substances behind half of Arctic warming

Washington, Jan 21

Ozone-depleting substances caused half of Arctic warming and sea ice loss from 1955 to 2005, causing about a third of all global warming during that period, reveals a significant study.

A scientific paper published in 1985 was the first to report a burgeoning hole in Earth’s stratospheric ozone over Antarctica.

The discovery left scientists into a huddle to determine the cause which happened to be ozone-depleting substances – long-lived artificial halogen compounds entirely manmade and popularly used as refrigerants, solvents and propellants.

The new study from researchers at Columbia University and published in the journal Nature Climate Change examined the greenhouse warming effects of ozone-depleting substances (ODS).

It found that the ozone-depleting substances acted as a strong supplement to carbon dioxide, the most pervasive greenhouse gas.

“We showed that ODS have affected the Arctic climate in a substantial way,” said researcher Michael Previdi from Lamont-Doherty Earth Observatory.

The scientists reached their conclusion using two very different climate models that are widely employed by the scientific community, both developed at the US National Center for Atmospheric Research.

The results highlight the importance of the Montreal Protocol, which has been signed by nearly 200 countries.

“Climate mitigation is in action as we speak because these substances are decreasing in the atmosphere, thanks to the Montreal Protocol,” said Lorenzo Polvani, lead author of the study.

“In the coming decades, they will contribute less and less to global warming. It’s a good-news story”.

In the 1980s, a hole in Earth’s stratospheric ozone layer, which filters much of the harmful ultraviolet radiation from the sun, was discovered over Antarctica. Scientists quickly attributed it to ODS.

The world sprang into action, finalizing a global agreement to phase out ODS.

The Montreal Protocol was signed in 1987 and entered into force in 1989. Due to the swift international reaction, atmospheric concentrations of most ODS peaked in the late 20th century and have been declining since.

However, for at least 50 years, the climate impacts of ODS were extensive, revealed the new study.

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