International cooperation on ozone-depleting chemicals is helping to return the southern jet stream to a normal state, according to a study published in the journal Nature that reinforces the scientific view that human action can halt global heating. The powerful wind shapes the weather and ocean currents in the southern hemisphere. It was sent off course – tracking southwards and disrupting weather patterns – by depletion of the ozone layer due to manmade chlorofluorocarbons and hydrochlorofluorocarbons. The chemicals, found in fridges, aerosols and industrial processes, were phased out from 1987 under the UN Montreal protocol. The jet stream has since stopped moving south and the “hole in the ozone layer” has shrunk to its smallest size since 1982. Alexey Karpechko, a reviewer of the study, said: “This is good news, definitely. It shows our actions can stop climate change. We can see coordinated action works … we can manipulate the climate both ways: in a wrong way and by reversing the damage we have done.”

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(From the Guardian – 25.3.20)