LONDON    -   The ozone hole over Antarctica this year could be one of the smallest seen in three decades, say scientists.

Observations of the gas’s depletion high in the atmosphere demonstrate that it hasn’t opened up in 2019 in the way it normally does.

The EU’s Copernicus Atmosphere Monitoring Service (CAMS) says, “It’s currently well under half the area usually seen in mid-September.”

The hole is also off-centre and far from the pole, the EU agency adds. CAMS’ experts, who are based in Reading, UK, are projecting stable levels of ozone or a modest increase in the coming days.

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

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

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