The annual Antarctic ozone hole over Antarctica has reached nearly record-breaking proportions this year, causing concern among scientists. Satellite imagery taken on September 16th revealed that the depleted ozone area had reached 26 million square kilometres, approximately three times the size of Brazil, according to the Copernicus program, the European Union’s Earth observation program.
According to the reports, the expansion of the ozone hole has been rapid since mid-August, making it one of the largest ever observed, according to Antje Inness, a senior scientist at the Copernicus Atmosphere Monitoring Service. The size of this ozone hole primarily depends on the strength of a powerful wind band encircling Antarctica, a result of Earth’s rotation and temperature differences between polar and moderate latitudes.
The agency explained that a strong band of wind acts as a barrier, preventing the exchange of air masses between polar and temperate latitudes. As a result, air masses become isolated over the polar regions and eventually cool down during winter. Despite this, the exact reason behind the current ozone concentrations is still unclear.
Typically, ozone levels return to normal by mid-December as temperatures in the stratosphere rise in the southern hemisphere, slowing down ozone depletion and weakening the polar vortex, as explained by Copernicus.
The origins of the ozone depletion phenomenon traced back to the widespread use of harmful chlorofluorocarbons (CFCs) in products such as refrigerators and aerosol cans during the 1970s and 1980s. This depletion in the upper atmosphere allowed the ozone layer above Antarctica to thin out, as per Copernicus.
In 1989, the Montreal Protocol, a universally ratified United Nations treaty, came into effect, phasing out the production of ozone-depleting substances, including CFCs.
Last month, the U.S. Environmental Protection Agency decided to postpone the tightening of ozone pollution standards until after the 2024 presidential election.