Ozone layer is healing, and air is getting cleaner
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.
Its healing is largely thanks to the Montreal Protocol agreed internationally in 1987, which banned the production of ozone-depleting substances.
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.
But these trends stopped and began to reverse slightly in 2000.
It is important to know which aspects of climate change have been caused by carbon dioxide emissions, which are continuing to rise, versus ozone depletion, which is now stopping and reversing.
Despite the ban on ozone-depleting substances, these chemicals have very long lifetimes in the atmosphere, so full ozone recovery isn’t expected to take place for several decades.
The ozone layer is expected to recover to 1980s levels by the 2030s for the northern hemisphere mid-latitudes and by the 2050s for the southern mid-latitudes, while the Antarctic ozone hole will probably recover a bit later in the 2060s.