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.

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.

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.

Scientists say that while losses started earlier than normal this year, they were truncated by a sudden warming event that lifted temperatures in the stratosphere by 20-30 degrees. This destabilised the ozone destroying process.

Richard Engelen is the deputy head at CAMS. He says the small size seen so far this year is encouraging but warns against complacency.

“Right now I think we should view this as an interesting anomaly. We need to find out more about what caused it.” he told BBC News..

“It’s not really related to the Montreal Protocol where we’ve tried to reduce chlorine and bromine in the atmosphere because they’re still there. It’s much more related to a dynamical event. People will obviously ask questions related to climate change, but we simply can’t answer that at this point.”

Source: https://www.bbc.com/news/science-environment-49714987