Matthew Tulley from Australia’s Bureau of Meteorology says the hole has begun to show signs of healing because of the international agreement to phase out the production of ozone-depleting chemicals in the 1987 Montreal Protocol.

Recent observations indicate that the level of ozone-depleting substances has decreased by 4 percent since 2001.

But since chlorine and bromine compounds have long lifetimes in the atmosphere, a recovery of atmospheric ozone is not likely to be noticeable until 2020 or later.

It could take until the end of the century for stratospheric ozone to return to where they were before the depleting chemicals began to destroy it.

Ozone is a protective layer found about 25 km above us mostly in the stratospheric layer of the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays.

The thinning of this layer increases the risk of skin cancer, cataracts and harm to marine life.

Photo: NASA's Ozone Watch