The ozone layer absorbs about 98% of harmful cancer-causing UV light - so it is vitally important. Levels were found to be reduced in the 1980s, caused by chlorofluorocarbons (CFCs) and halons, gases used in spray cans, fridges and insulation.
The research was part of a four-yearly review of the Montreal Protocol, a 1987 ban on man-made gases that harm the ozone layer, which found that these gases in the atmosphere were decreasing in the long-term.
It is possible the healing of the ozone hole above Antarctica may insulate the continent and accelerate climate warming, but report co-author Ross Salawitch, an atmospheric scientist at the University of MI, said the immediate effects of ozone damage were such that it would be "incredibly irresponsible" not to protect the depleted ozone layer.
The report stated: "The Antarctic ozone hole is recovering while continuing to occur every year".
Paul Newman of Nasa, joint chairman of... The Kigali Amendment to the Protocol, made in 2016, deals with phasing down the use of other substances like HFCs which are not ozone-depleting but are quite damaging for the climate due to its high global warming potential.
Referring to projected rates, the report says the northern hemisphere and mid-latitude ozone is "scheduled to heal completely by the 2030s followed by the southern hemisphere in the 2050s and polar regions by 2060". "We stopped that", Paul Newman, a NASA scientist and co-chairman of the new United Nations report, told the AP. "If ozone-depleting substances had continued to increase, we would have seen huge effects".
"It shows that the ozone layer is under fix, and highlights areas that must be strengthened for it to be an equally successful platform to phase out HFCs to limit global warming", said Shikha Bhasin, programme lead, Council on Energy, Environment and Water (CEEW). It's unclear, however, how much more warming can be expected once the Antarctic ozone hole heals.
"The Montreal protocol is one of the most successful multilateral agreements in history for a reason", said Erik Solheim, head of UN Environment. Since 2000, it has increased by about 1 to 3 percent per decade, the report said.
But an amendment to the Montreal Protocol is set to come into place next year which will ban the chemical.
"I don't think we can do a victory lap until 2060", Newman said.