A false-color view of total ozone over the Antarctic pole is seen in this NASA handout image released October 24, 2012. Reuters/NASA/Handout

A United Nations study has said that the ozone layer, which shields the planet from deadly cancer-causing ultraviolet rays, is showing signs of thickening again, after years of depletion. The ozone hole that appears over Antarctica every year has also stopped growing but it will take a decade before it starts to shrink, according to the report.

A fall in the use of chlorofluorocarbons, or CFC, in consumer products, driven by strong political will, is the reason for the ozone layer's recovery, according to scientists and researchers from the World Meteorological Organization, or WMO, and the United Nations Environment Programme, or UNEP, which jointly published the report.

"International action on the ozone layer is a major environmental success story," WMO Secretary-General Michel Jarraud said in a UNEP statement. "This should encourage us to display the same level of urgency and unity to tackle the even greater challenge of climate change."

The report credited the Montreal Protocol, which it called "one of the world's most successful environmental treaties," for the recovery of the ozone layer, which it projects will help prevent two million cases of skin cancer by 2030, besides preventing damage to humans' immune systems as well as wildlife and agriculture. In 1987, the Protocol banned ozone-depleting chemicals such as CFCs, which were at the time widely used in refrigerators and spray cans.

Dr. Ken Jucks of NASA reportedly told BBC News that humans "have started to do the right thing in order to convert the atmosphere back towards what it was before the industrial revolution started."

However, scientists are not sure if the ozone hole can heal itself, BBC reported, citing David Vaughan from the British Antarctic Survey, who reportedly called for cautious optimism in reacting to the data, and added that numbers from a BAS study could help confirm the WMO's findings.

"Our own data from the Antarctic will take a few weeks to process but we hope to confirm the findings," Vaughan told BBC.

Ozone should recover to its pre-1980 levels by the middle of this century and slightly later for Antarctica where the protective gas layer gets extremely thin between August and December every year, the WMO reportedly said, adding that the process can be speeded up by almost 11 years if existing stocks of ozone-depleting products, such as those found in old refrigerators and fire extinguishers are destroyed.

However, earlier this week, the WMO reported that atmospheric greenhouse gases, fuelling climate change, have reached a record high. And, fighting this will be a challenge because harmful carbon dioxide, or CO2, is at the center of modern-day life and finding substitutes will not be easy, the BBC reported.