Greeny News

similar sized holes for the first time, scientists say, because the combination of wind patterns and extreme cold

a huge hole appeared in the protective ozone layer in the Arctic in 2011 was the largest recorded in the northern hemisphere, despite the sudden appearance of the hole was not due to anthropogenic causes, the scientists said in a report Monday.

The ozone layer in the stratosphere acts as a giant shield against the sun's ultraviolet (UV), which can cause skin cancer and cataracts. Since the 1980s, scientists have traced the size of each summer ozone hole above Antarctica.

years near the holes were so large they covered the entire continent and spread to parts of South America.

during extreme events, up to 70% of the ozone layer can be destroyed before it recovers months later. The hole above the Arctic has always been much smaller - until March of this year, when a combination of strong winds and intense cold at the top of the atmosphere that creates the right conditions for such presented, the chemicals eat the ozone layer damaging chlorine.

The results, published Monday in the journal Nature, show that the hole had opened in northern Russia, parts of Greenland and Norway, that is, people in these areas was may have been exposed to high levels of UV radiation.

The scientists say man-made chemicals like chlorofluorocarbons (CFCs) destroy ozone in the stratosphere, sunlight breaks after complex chemicals into simpler forms that react with ozone. Although some chemicals are covered by a United Nations treaty that aims to prevent their use will be decades before being completely removed from production.