The size of 2020's ozone hole over Antarctica is the largest it has been in years, with an area of about 25 million square kilometers (9.7 million square miles) – nearly the same size as that of 2015's ozone hole. That’s the size of Russia and Australia combined. The ozone hole, also the deepest in years, reached its maximum this year on October 2.
The hole is not constant but instead fluctuates with the seasons. From August to October, the hole increases and reaches its largest width. After, it starts to shrink again, returning to normal levels towards the end of December.
The current observations show quite a difference from what we saw last year. In 2019, the hole was at the smallest it has been in 30 years at 16.4 million square kilometers (6.3 million square miles). The general trend is positive with the hole closing. Over the last two decades, the layer has recovered 1 to 3 percent every 10 years, but the variability year after year shows the long-lasting damage that humans can cause to the environment.
The latest measurements were performed by the European Space Agency's Copernicus Sentinel-5P satellite.
“Our observations show that the 2020 ozone hole has grown rapidly since mid-August, and covers most of the Antarctic continent – with its size well above average. What is also interesting to see is that the 2020 ozone hole is also one of the deepest and shows record-low ozone values,” Diego Loyola, from the German Aerospace Center who ran the analysis, said in a statement.
Ozone is a molecule made of three oxygen atoms and spread in a thin layer in the atmosphere. It absorbs ultraviolet radiation from the Sun, protecting life from this harmful light. The use of chlorofluorocarbons in the 70s and 80s led to the depletion of this precious gas, and a hole in the layer formed above Antarctica.
Due to the Montreal Protocol of 1987, those dangerous chemicals were phased out and the hole is now slowly repairing itself. The differences year in and year out depend on several factors, including the speed of polar winds.
ESA’s mission manager for Copernicus Sentinel-5P, Claus Zehner, commented: “Based on the Montreal Protocol and the decrease of anthropogenic ozone-depleting substances, scientists currently predict that the global ozone layer will reach its normal state again by around 2050.”