Modest ozone hole despite optimal conditions of exhaustion, say scientists

Although colder than average temperatures in the Antarctic stratosphere have created Ideal conditions for the destruction of ozone in 2018, the decrease in levels of chemicals that exhausted has prevented the hole Scientists at NASA and the National Oceanic and Atmospheric Administration (NOAA) have revealed that They were as big as 20 years ago.

The results showed that the hole in the ozone layer that forms in the upper atmosphere over Antarctica each September was a little above average in 2018. [19659005] "The colder temperatures this year would have left us with a much larger hole in the ozone layer if chlorine was still at the year 2000 level," said Paul A. Newman, responsible Earth scientist. Science at NASA's Goddard Space Flight Center in the Greenbelt of Maryland

According to NASA, the hole in the ozone layer reached an average area of ​​22.9 km 2 in 2018.

NO AA scientists said colder temperatures in 2018 allowed the near-complete elimination of ozone in a deep layer 5 km above the South Pole. This layer is the place of active chemical depletion of ozone in polar stratospheric clouds.

"Even with the optimal conditions this year, the ozone loss was less severe in the upper layers of the altitude, which we expected due to lower chlorine levels. "We see in the stratosphere," said NOAA scientist Bryan Johnson.

The nations of the world began eliminating the use of substances that deplete the ozone layer in 1987 under from an international treaty called the "Montreal Protocol".

The hole in the 2018 ozone layer was strongly influenced by a stable and cold Antarctic vortex – the stratospheric low pressure system that s & # 39; 39, flows clockwise in the atmosphere above Antarctica.

In 2016 and 2017, the milder temperatures of September limited the formation of polar stratospheric clouds and slowed down the ozone formation, the growth of the hole. Before starting to recover, the hole in the ozone layer reached an area of ​​19.7 km 2

In 2016, the hole had reached 20.7 km 2

However, its current area is still significant compared to the 1980s, the depletion of the ozone layer over Antarctica was detected for the first time. Atmospheric concentrations of man – made ozone – depleting substances increased to the year 2000.

Since then, they have been slowly decreasing, but remain high enough to cause a significant loss of ozone. # 39; ozone.