The Antarctic ozone hole remains at the same size as North America, the new data from NASA shows. Scientists previously expected to reduce in size quickly when the use of ozone-depleting chlorofluorocarbons (CFCs) substances were banned 27 years ago, but it remains the same level as it is in 2010 to 2013.
It will take long time for the ozone to recover because the CFCs were long-lived.Dr. Jonathan Shanklin
The ozone hole is in the thin layer of gas, which helps shield life on Earth from potentially harmful ultraviolet solar radiation that can cause skin cancers.
The hole, which forms annually in the August to October period, had peaked in September 9 when monitors at the South Pole showed it to cover 24.1m square km (9.3m square miles).
In comparison, the largest ozone hole area recorded to date on a single day was in September 2000 at about 29.9 million square kilometers.
Scientists remain uncertain why the hole has not reduced more since the Montreal Protocol agreement was signed by countries in 1987.
This global treaty bans the use of CFCs substances that were widely-used in household and industrial products such as refrigerators, spray cans, insulation foam and fire suppressants.
Dr. Jonathan Shanklin, emeritus professor at the British Antarctic Survey in Cambridge, one of the three scientists who discovered the hole in the 1980s, said it will take long time for the ozone to recover because the CFCs were long-lived.
He said the reason why the ozone is not healing more quickly is because the interaction between climate change and the ozone hole was complex.
Shanklin explained that the hole is affecting the climate of Antarctica and Australia, and is also being affected by it.
Last month, the UN Environment Program and the World Meteorological Organization said there were “positive indications” that the ozone layer was on track to recovery. But also warned it might take a further 35 years or more to recover to 1980 levels.
They said had the Montreal Protocol not sign, the atmospheric levels of ozone depleting substances could have increased tenfold by 2050.
This archive content was originally published November 2, 2014 (www.betawired.com)