The hole in the ozone layer over Antarctica is healing.
Researchers discovered reversing changes to the flow of winds over the southern hemisphere.
The most significant impact can be seen in the southern hemisphere jet stream. It had been reportedly moving further south due to ozone depletion, but that appears to be reversing.
Scientists from the University of Colorado Boulder claim the healing is a result in part to a ban on ozone-depleting substances (ODS) in the 1980s. However, the lead author of the study, Antara Banerjee, says this change may be only temporary. She points out the impact of rising carbon dioxide levels and more ODS coming from China.
Before the 2000s, the mid-latitude upper-atmosphere wind had been gradually moving towards the South Pole. Meanwhile, another hurricane-causing airstream was expanding. This was causing changes in rainfall patterns and ocean currents in the southern hemisphere. As a result, countries like Australia suffered severe droughts.
With a range of computer simulations, researchers showed that the jet stream stopped moving south at the same time as the ozone hole began healing.
If the upper-atmosphere wind reverses its southwards movement, it could bring back rains to the affected countries, preventing further droughts.
In 2019, the Antarctic ozone hole reached its smallest annual peak on record, since it was discovered in 1982. However, this is believed to be a temporary fix. Scientists reckon this record may be caused by unusually mild temperatures in that layer of the atmosphere.
Additionally, the team working on the study confirms that there has also been a surge in ozone-depleting chemicals coming from China’s industrial regions.
“We term this a “pause” because the poleward circulation trends might resume, stay flat, or reverse. It’s the tug of war between the opposing effects of ozone recovery and rising greenhouse gases that will determine future trends.”
She adds that the major discovery her team made was proof that a global protocol like the one in Montreal that banned ODS can pause or reverse environmental harm. The whole study is published in the journal Nature.