The ozone layer, which develops a hole over Antarctica every year that grows to its largest extent in September and October, is weaker this year than last.
The hole, created by air pollution, has reached an extent already this year that exceeds the extent recorded in 2007, according to the World Meteorological Organization, a United Nations agency.
After decades of chemical attack, it may take another 50 years or so for the ozone layer to recover fully. As the Montreal Protocol has taught us, when we degrade our environment too far, nursing it back to health tends to be a long journey, not a quick fix, said Ban Ki-moon, Secretary-General of the United Nations.
Today is the International Day for the Preservation of Ozone Layer.
The Montreal Protocol, signed in 1987, is heralded not only as a success, because it resulted in nations across the globe agreeing to phase out the use of chemicals that cause ozone depletion, but also as a global warming bellwether: If the world can tackle this atmospheric problem, it can also tackle climate change.
The fact that the hole is larger this year than last doesn't indicate a new trend, necessarily. There's an yearly ebb and flow that researchers say is trending in the right direction.
At 16.8 million square miles, the ozone hole is bigger than North America. The hole allows UV radiation to penetrate the stratosphere, leading to an increase in cancer risk and other health and environmental problems on the Earth's surface.
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