THE hole in the ozone layer is slowly beginning to close - thanks to the ban on CFCs.
It is nearly 20 years since harmful chlorine gases, then common in fridges and aerosols, were outlawed.
Ozone levels, once shrinking at an alarming rate, are now stable and have possibly even risen slightly over the past decade, scientists revealed.
Natural factors, such as a lack of volcanic eruptions, have also helped.
Dr Betsy Weatherhead, who led the study, said: "The ozone layer is responding to decreases in chlorine levels in the atmosphere due to the levelling off and decrease of CFCs."
But the American expert warned: "We're not out of the woods yet and the ozone recovery process still faces a number of uncertainties."
She said other chemicals remained a danger, such as greenhouse gases from cars and nitrous oxide (N2O), produced by fertilisers.
Dr Weatherhead added: "In another 50 years CFCs won't be the dominant factor controlling ozone. Instead, we think it will be factors like greenhouse gases, N2O and methane."
Fellow experts in the US-Denmark study say other problems such as global warming make ozone levels unlikely to return to pre-1980 figures.
A blanket of the gas, 10 to 20 miles above Earth, shields us from harmful effects of the sun's ultraviolet rays.
But a hole was first discovered over Antarctica and the South Pole in the 70s - marked by the blue patch in the Nasa photo above.
The problem remains most severe at both poles. However, the stratosphere above much of Europe and North America has seen a 10 per cent reduction in ozone cover.
The 1987 Montreal Protocol banned the release of CFCs, also found in air conditioning and industrial cleaners.
The legally binding accord is backed by more than 180 countries.
THERE is "clear evidence" mankind is behind global warming, a report for the US Government says.
It found the lower atmosphere as well as the Earth's surface is heating up - and blamed wrong data for some US sceptics' claims that it is not.
Temperature rises over the past 50 years "cannot be explained by natural processes alone", researchers added.