2019 ozone hole could be smallest in three decades

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 a decline in the area of thinning in coming days.

Ozone is a molecule that is composed of three oxygen atoms. It is responsible for filtering out harmful ultraviolet radiation from the Sun.

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.

This past week has seen the area of deep thinning cover just over five million square km. This time last year it was beyond 20 million square km, although in 2017 it was just above 10 million sq km.