At this time of year, as the sun rises over Antarctica, a “hole” opens up in Earth’s ozone layer.
But the hole will continue to open each year for at least another four decades because of the long lifetimes of gases emitted last century.
Even though most ozone-depleting gases are now banned, it will take decades before they are gone from the stratosphere.
Ozone depletion causes the prevailing westerly winds at southern mid-latitudes (the “Roaring Forties”) to strengthen and shift toward Antarctica during summertime. This has increased surface melting on Antarctic ice shelves and is changing summertime rainfall and temperature patterns in New Zealand and Australia.
Recent research shows mega-wildfires such as the Australian bushfires of 2019 can contribute to ozone depletion. An increase in civilian rocket launches is expected to put more ozone-depleting gases and aerosols into the stratosphere.
Higher amounts of debris from satellite re-entry may contribute to ozone loss by introducing aerosols into the upper atmosphere.
On top of these issues come controversial “geoengineering” proposals, whereby aerosols are deliberately injected into the stratosphere to reduce the rate of global warming.