Finally, some good environment news: The Earth's protective ozone layer has been healing at a rate of around 2 percent since 2000, and could be completely healed by the middle of the century.

That's according to a United Nations report that praised the rate of success, which it attributed to the historic 1987 Montreal Protocol's ban on chlorofluorocarbons (CFCs) and other ozone-depleting substances.

If the current reductions in ozone-depleting emissions are sustained, the Northern Hemisphere could be healed by the 2030s and the Southern Hemisphere healed by the 2050s, the report detailed.

The hole above Antarctica, which was once as large as North America, could be completely recovered by the 2060s, the report found.

The 30th meeting of parties to the Montreal Protocol recently wrapped up in Ecuador with a unanimous decision to strengthen its enforcement.

Had it not been for the global agreement, much of the Earth's ozone layer would have been destroyed by 2065.

That would have had devastating consequences as the ozone layer protects life on the planet from the sun's damaging ultraviolet light, which causes skin cancer and cataracts in humans and other animals.

Mysterious spike in emissions

Although, the Montreal Protocol successfully reduced the release of ozone-depleting substances, researchers had been baffled by a slowdown in reductions of one particular gas, CFC-11.

The Environmental Investigation Agency (EIA) last July uncovered the source: China (also a party to the Montreal Protocol).

Read more: China blamed for baffling rise in ozone-depleting gas

Posing as buyers, investigators with the London-based green group found that 18 factories in China were still manufacturing banned CFCs for sale as plastic foam in the booming construction sector, because they were cheaper.

The EIA said several companies across China admitted to exporting CFCs by mislabeling them as hydrofluorocarbon (HFC) compounds. The Chinese government has since pledged to shut down those factories.

"If these CFC-11 emissions had continued at this level, the recovery of the Antarctic ozone hole would be delayed 7 to 20 years," Paul Newman, co-chairman of the recent UN ozone layer report and chief Earth scientist at NASA's Goddard Space Flight Center, told DW.