The 2021 Antarctic ozone hole in context

#Ozone, #Copernicus, #Antarctic

Published on 19 January 2022

The 2021 Antarctic ozone hole closed towards the end of December last year, ending another one of the longest lasting Antarctic ozone hole seasons on record. The formation and evolution of the ozone hole each year is caused by complex chemical and meteorological processes and, throughout the year, scientists from the Copernicus Atmosphere Monitoring Service (CAMS)—implemented by  ECMWF on behalf of the European Commission—track the development and recovery of the hole to provide quality-assured information about the state of the ozone layer.

CAMS scientists confirmed at the end of last month that the 2021 Antarctic ozone hole closed on 23 December, only a few days earlier than in 2020. Consequently, the 2021 ozone hole was one of the largest and longest-lived holes on record: in fact the record shows that only twice - in 1999 and 2020 – did the ozone hole close later than in 2021.

Time series of average, maximum and minimum extent of the ozone hole for the period 7 September -13 October (1979-2021)

Time series of average, maximum and minimum extent of the ozone hole for the period 7 September -13 October (1979-2021)

After a rather standard start at the beginning of August, expansion of the ozone hole picked up in pace in the first two weeks of September to reach an extent larger than 75% of ozone holes at that stage in the season since 1979 and, as is the case most years, it had reached the size of Antarctica (14.2 million square kilometers) by early September. It continued to expand rapidly over the following weeks to reach its maximum extent for the year of 24.7 million square kilometers by the start of October – over 700,000 square kilometers greater than the maximum reached in 2020, making it the eighth largest ozone hole since records began in 1979.

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