The ozone layer over the Arctic is always particularly thin at this time of year during the annual cycle. However, it has shrunk to an above-average extent this winter due to the particularly low temperatures in a high air layer.
Jülich (dpa) - The ozone layer over the North Pole has shrunk above average this winter. The reason for this are particularly low temperatures in a high layer of air, the stratosphere, and a stable polar vortex, the Research Center Jülich announced on Thursday.
According to this, the ozone content has steadily decreased over the past three months and is now at the beginning of March 18 percent lower than in winters without special weather influences. Currently, however, there is no danger from high UV radiation due to the still low position of the sun.
The ozone layer over the Arctic is always particularly thin at this time of year during the annual cycle. According to the Jülich stratospheric researchers Jens-Uwe Grooß and Rolf Müller, however, it will soon recover. "If it gets too warm for these ozone-depleting processes, the spook is quickly over," said Müller. As soon as the temperatures rise in the next few days or weeks, the ozone depletion is stopped and the measured values normalize.
In the past decade, ozone depletion was even greater than in the past decade only in winter 2015/16. Even then, a cold period was the cause.
The production of ozone-depleting CFCs (chlorofluorocarbons) has long been banned. Nevertheless, no clear trend towards recovery has yet been discernible in the Arctic, said Müller. CFCs have a lifespan of 50 to 100 years. In the long term, a recovery can be expected - in roughly 50 years, if the production of ozone-depleting substances does not increase again, said Müller.
The ozone hole over Antarctica, the discovery of which in 1985 led to the adoption of the Montreal Protocol and the gradual ban on CFCs, seems to be slowly closing. In 2019 it was as small as it had been in around 30 years.
Daily updated ozone loss calculations
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