Scientists from the UK and US have found that the hole has shrunk by over 4 million sq.km since 2000
Research shows the hole in the ozone layer above Antarctica appears to be healing.
The findings, published today in Science, confirm the first signs of healing of this important shield that protects the Earth from the sun's harmful ultraviolet rays.
The research attributes this improvement to the 1987 Montreal Protocol, which called for a ban on the use of chlorofluorocarbons (CFCs) - at the time they were widely used in cooling appliances and aerosol cans.
Lead author of the study, Professor Susan Solomon said: “We can now be confident that the things we’ve done have put the planet on a path to heal.
“We decided collectively, as a world, ‘Let’s get rid of these molecules’? We got rid of them, and now we’re seeing the planet respond.”
Co-author Dr. Anja Schmidt added: “The Montreal Protocol is a true success story that provided a solution to a global environmental issue.”
The study also shed new light on the effect of volcanic activity on ozone depletion. The measurements, taken from the month of September in each year, show that recovery has varied due in part to recent eruptions.
“Despite the ozone layer recovering, there was a very large ozone hole in 2015,” said Dr. Schmidt.
“We were able to show that some recent, rather small volcanic eruptions slightly delayed the recovery of the ozone layer.
“That is because such eruptions are a sporadic source of tiny airborne particles that provide the necessary chemical conditions for the chlorine from CFCs introduced to the atmosphere to react efficiently with ozone in the atmosphere above Antarctica. Thus, volcanic injections of particles cause greater than usual ozone depletion.”
CFCs last for up to 100 years in the atmosphere, so it will be many years before they disappear completely and the true extend of the healing is seen.