The hole in the 2019 ozone layer could be the smallest in three decades

According to scientists, the hole in the ozone layer over Antarctica this year could be one of the smallest for three decades.

Observations of the depletion of gas in the atmosphere show that it did not open in 2019 as usual.

The EU Copernicus Atmosphere Monitoring Service (CAMS) indicates that its area is currently well below half that usually seen in mid-September.

The hole is also eccentric and far from the pole, adds the European agency.

The CAMS experts, based in Reading, UK, predict stable ozone levels or a modest increase in the coming days.

Ozone is a molecule composed of three atoms of oxygen. It is responsible for filtering the harmful ultraviolet rays of the Sun.

The gas is constantly being produced and destroyed in the stratosphere, about 20-30 km above the Earth.

In an unpolluted atmosphere, this cycle of production and decomposition is in equilibrium. But chlorine and chemicals containing bromine released by human activities have unbalanced the process, resulting in a loss of ozone that peaks in the Antarctic spring in September / October.

The Montreal Protocol signed by governments in 1987 sought to restore the situation by banning the production and use of the most damaging chemicals.

Last week, the deep thinning area spans just over five million square kilometers. Last year, at that time, it exceeded 20 million square kilometers, but in 2017, it was just over 10 million square kilometers.

Vincent-Henri Peuch, who heads CAMS, said the small size observed so far this year is encouraging, but warns against complacency.

"The recovery of the ozone layer is dependent on climate change, as long-term cooling in the stratosphere can aggravate the loss of ozone and delay the process." The second most abundant chlorofluorocarbon (CFC-11) has already been detected last year, "he said.

"It is very important to maintain international efforts to monitor the recovery of the ozone layer over time and the annual events related to ozone holes."

CAMS is an EU service run by the European Center for Medium-Range Weather Forecasts.

It has access to a range of spatial and terrestrial observations. The main sources of data include the European Metop meteorological satellites and the own European Sentinel-5P aircraft. The four platforms are all equipped with ozone sensors and regularly cross the pole.

Thinning conditions occur every year, just as Antarctica emerges from the winter. The reactions that destroy the gases in the cold stratosphere are triggered by the return of the sun to high latitudes.

Scientists say that although the losses began earlier than normal this year, they have been truncated by a sudden warming of the upper atmosphere.

According to the 2018 scientific assessment of the depletion of the ozone layer sponsored by WMO, one could expect a recovery of the ozone layer at the levels. from before 1970, around 2060.