VATIS UPDATE Article

US researcher Prof. Susan Solomon and colleagues, including researchers from the University of Leeds, the United Kingdom, have found the first clear evidence that the thinning in the ozone layer above Antarctica is starting to heal. The scientists said that in September 2015 the hole was around 4 million sq km smaller than it was in the year 2000 – an area roughly the size of India. The gains have been credited to the long term phasing out of ozone-destroying chemicals. The study also sheds new light on the role of volcanoes in making the problem worse.

Researchers carried out detailed measurements of the amount of ozone in the stratosphere between 2000 and 2015. Using data from weather balloons, satellites and model simulations, they were able to show that the thinning of the layer had declined by 4 million sq km over the period. They found that more than half the shrinkage was due solely to the reduction in atmospheric chlorine. Normally measurements are taken in October when the ozone hole is at its largest. The study has been published in the journal Science.

However this team believed they would get a better picture by looking at readings taken in September, when temperatures are still low but other factors that can influence the amount of ozone, such as the weather, are less prevalent. “Even though we phased out the production of CFCs in all countries including India and China around the year 2000, there’s still a lot of chlorine left in the atmosphere,” said Prof Solomon. One finding that puzzled researchers was the October 2015 reading that showed the biggest ozone hole on record over Antarctica. The scientists believe that a key contributor to the record hole was volcanic activity.