For a bit of good news in 2020, reports from NASA and the National Oceanic and Atmospheric Administration (NOAA) claim that the ozone layer above Antarctica has recovered significantly. This has led to a lot of positive changes in the Southern Hemisphere’s atmosphere and its air currents.
According to the report, the cause of this change can be traced back to the Montreal Protocol – a 1987 international agreement to cease the production of ozone depleting substances (ODSs). This is especially good for the rainfall patterns in the Southern Hemisphere as the ozone depletion in the last several decades had driven the upper atmosphere’s air current or “jet streams” too much to the south.
The scientists from NASA and NOAA used various computer simulations and models to determine the cause behind the ozone layer’s apparent healing and the subsequent steadying of the air currents. They have determined that the change is due to more than just the natural shifts in winds and the Montreal Protocol deserved a big part of the credit.
What does this mean?
The rapid depletion of the ozone layer over Antarctica in the last several decades has had a lot of negative consequences over the climate in the Southern Hemisphere. One such example is the regional rainfall decline in Australia which has harmed the country’s climate and agricultural capabilities. If the “healing” of the ozone layer continues, rainfalls in Australia can be even expected to return.
Ian Rae, an organic chemist from the University of Melbourne commented that “The ‘weather bands’ that bring our cold fronts have been narrowing towards the south pole, and that’s why southern Australia has experienced decreasing rainfall over the last thirty years or so. If the ozone layer is recovering, and the circulation is moving north, that’s good news on two fronts (pun not intended).”
This is far from a definitive victory
There is a reason why scientists are using the word “pause” – this positive change may easily end up being temporary. Even though last year the Antarctic ozone hole hit its smallest annual peak since 1982 due to the reduction of ODSs, those are not the only problem that needs solving.
One of the biggest issues in recent years is the overuse of certain ozone-depleting chemicals, particularly from China’s industrial regions in the north-eastern parts of the country.
Atmospheric chemist Antara Banerjee from the University of Colorado Boulder explained it like this: “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.”
Nevertheless, in a year like 2020, we’ll take “a win” wherever we can. The current pause and healing of the Antarctic ozone layer is great news and proof that the Montreal Protocol is working. If we can retain this progress and even build on it, the atmosphere of the Southern Hemisphere can continue improving.
This can have amazing benefits to the climate, weather, agriculture, and economics of dozens of countries and regions in Africa, South America, and Australia which are currently hit by droughts untimely storms, and other problems such as this year’s abnormal locust swarms.