Ozone-depleting Substances Caused Half of Late 20th-Century Arctic Warming

Damage to the ozone layer might also be liable for half of Arctic warming over 50 years, a new study claims.

An international team of researchers says the findings highlight ozone-depleting substances (ODS) as an unrecognized source of twentieth-century Arctic climate change.

ODS, a set of very harmful greenhouse gases, are halogen compounds that destroy the protective layer of ozone in the upper atmosphere.

These compounds could also be liable for 50 percent of Arctic warming and sea ice loss from 1955 to 2005 and almost one 0.33 of global warming at some point in that period.

 The researchers wrote in Nature Climate Change that the compounds have long been recognized as potent greenhouse gases aside from causing the ozone hole over Antarctica.

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"ODS are much more powerful greenhouse gases on a molecular basis compared to carbon dioxide," the researchers added.

ODS was developed in the 1920s and 30s and used as refrigerants, propellants, and solvents in the 20th century. These molecules have been emitted into the atmosphere in substantial quantities in the late 50s.

But the invention of the ozone hole of Antarctica, which causes specific atmospheric and chemical conditions there at certain times of the year, caused the phase-out of the production.

The ozone later is now in gradual recovery because of ODS emissions, with the help of the nations agreeing to defend the ozone layer since 1987.

However, ODS are mighty greenhouse gases and have lengthy atmospheric lifetimes, an excellent way to add to the anthropogenic greenhouse effect.

The research lead author Lorenzo Polvani and his colleagues at Columbia University in New York used a weather model to estimate how global warming could be attributed to ODS.

The team simulated worlds - one with natural and human emissions as measured between 1955 and 2005, and any other with ODCs and their ozone affects removed - to measure the net impact of ODS on climate.

Their fashions showed that when ODS numbers are saved fixed, compelled Arctic surface warming and forced sea-ice loss are best half of as large as whilst ODS are allowed to increase.

The results advise that persevered phase-out of ODS will help mitigate Arctic warming and sea ice melt in the destiny.

'If our findings are showed by destiny studies, the position of the Montreal Protocol as a prime environmental treaty will count on a brand new dimension,' the researchers state.

ODS include chlorofluorocarbons, hydrochlorofluorocarbons, and haloalkanes. These compounds are generally very strong in the Earth's lowest atmospheric layer. It only degrade under intense ultraviolet mild in the stratosphere - the second essential layer of Earth's atmosphere.

Once inside the stratosphere, they launch halogen atoms through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2).

This depletes the Earth's protective ozone layer, leaving humans uncovered to the sun's harmful radiation.

Susan Strahan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, found the result "interesting and provocative," but she is not yet convinced of its conclusions.

Both Strahan and Cecilia Bitz, a climate scientist at the University of Washington in Seattle, suggested that replicating the results in various climate models would be crucial for improving estimates of how CFCs bear for heating the Arctic.