The hole in the ozone layer above Antarctica is continuing to recover and it is leading to changes in atmospheric circulation – the flow of air over Earth’s surface that causes winds.
The ozone layer of the earth’s stratosphere absorbs the sun’s ultraviolet radiation. In 1985, the international community first recognized the depletion of the ozone layer an imminent threat because of its immediate ramifications including skin cancer.
The Montreal Protocol, signed in 1987, barred the use of ozone-depleting substances. Morocco is a party to the protocol, which is the only treaty in history signed by all UN-recognized countries.
Before 2000, a belt of air currents called the mid-latitude jet stream in the southern hemisphere had been gradually shifting towards the South Pole. Another tropical jet stream called the Hadley cell, responsible for trade winds, tropical rain-belts, hurricanes and subtropical deserts, had been getting wider.
Banerjee and her team found that both of these trends stopped and began to reverse slightly in 2000. This change couldn’t be explained by random fluctuations in climate, and Banerjee says they are a direct effect of the recovering ozone layer.
The researchers also note that the layer is capable of making full recovery but could also regress. Though the ozone layer has been recovering, emissions of carbon dioxide and other greenhouse gasses (GHS) are on a continuous rise, which offsets positive impacts.