The ozone layer is in much better shape than it would have been without the Montreal Protocol, the UN treaty that restricted the use of ozone-depleting substances, according to a new study in Nature Communications.
In the study the researchers used 3D computer models of atmospheric chemistry to investigate what would have happened to the ozone layer had the Montreal Protocol not been implemented in 1987.
The researchers found that the hole in the ozone layer over the Antarctic would have grown in size by an additional 40 per cent by 2013. Their model also suggests that had ozone-depleting substances continued to increase, the ozone layer would have become significantly thinner over other parts of the globe.
Atmospheric concentrations of ozone-depleted substances continued to rise even after the Montreal Protocol came into force as they can survive in the atmosphere for many years. They peaked in 1993 and have declined ever since.
“Our research confirms the importance of the Montreal Protocol and shows that we have already had real benefits. We knew that it would save us from large ozone loss ‘in the future’, but in fact we are already past the point when things would have become noticeably worse,” says lead author Professor Martyn Chipperfield from the University of Leeds.
Photo credit: NASA