The 'ozone hole' continues to shrink, according to NASA

The ozone hole over the South Pole on October 5, when it reached its largest extent this year. / NASA / Joshua Stevens

Science | Atmosphere

The area with a low concentration of this protective gas against ultraviolet radiation reaches 23.2 million square kilometers, much less than in 2006

The so-called 'ozone hole' has been reduced this year to 23.2 million square kilometers – the Iberian Peninsula has an area of ​​583,000 square kilometers – between September 7 and October 13, NASA and the United States Oceanic and Atmospheric Administration (NOAA). The region of the South Pole with low ozone concentration was in the last austral spring, when the 'hole' registers its annual maximums, slightly smaller than in 2021 -when it reached 23.3 million square kilometers- and was "well below below the mean observed in 2006, when the size of the 'hole' peaked."

Ozone (O3) is a gas that is found mainly (90%) in the stratosphere, between 10 and 50 kilometers high. It acts as a natural shield against harmful ultraviolet radiation, which causes skin cancer and cataracts. In the mid-1970s, scientists discovered a worrying depletion of the ozone layer over Antarctica due to the destruction of this gas by chlorofluorocarbons (CFCs) used in refrigerators and air conditioning systems. In 1987, 197 countries signed the so-called Montreal Protocol for the elimination of chlorofluorocarbons, which has since resulted in the progressive recovery of Antarctic ozone. According to scientists' forecasts, the layer of this gas over the South Pole could fully recover by 2050.

"With the passage of time, steady progress is being made and the hole is shrinking," Paul Newman, chief scientist for Earth sciences at NASA's Goddard Space Flight Center, said of the latest data. “We see some oscillations as weather and other factors cause the numbers to vary slightly from day to day and week to week. But, in general, (the 'hole in the ozone layer') has diminished in the last two decades”, affirms this expert.

Photographic sequence of the rise of a sounding balloon from the Amundsen-Scott base to measure the ozone column over Antarctica. /

Yuya Makino/IceCube

NASA and NOAA scientists monitor the 'ozone hole' with instruments aboard the Aura, Suomi NPP and NOAA-20 satellites. On October 5, those satellites observed a maximum single-day "ozone hole" of 26.4 million square kilometers, slightly larger than last year.

In addition, NOAA scientists working at the Amundsen-Scott South Pole Station, located at the geographic south pole, also record the thickness of the ozone layer by releasing balloons carrying instruments that measure the total amount of ozone between the surface terrestrial and the edge of space as they ascend. The world mean column ozone is about 300 Dobson units. On October 3, NOAA scientists recorded a minimum ozone value over the South Pole of 101 Dobson units. At that time, NASA explains, ozone was almost completely absent at altitudes between 14 and 21 kilometers, a pattern very similar to last year.

Some scientists were concerned about the possible impact of the eruption of the underwater volcano Hunga Tonga-Hunga Ha'apai (Tonga), which produced a tsunami in January that hit the islands of Tonga and a tidal wave in Fiji. They feared that something similar to 1991 would happen, when the Pinatubo eruption in the Philippines released huge amounts of sulfur dioxide that affected the ozone layer. This year, however, no direct impacts from the Tonga volcano eruption on Antarctica have been detected.