The ozone hole above the Antarctic has hit its maximum extent for the year. Due to warm temperatures, the opening in the protective atmospheric layer was the second smallest it has been for 20 years, scientists said Wednesday (Oct. 24).
etching to 8.2 million square miles (21.2 million square kilometers), an area roughly the size of all of North America, the ozone hole reached its peak on Sept. 22. The largest one recorded to date spanned 11.5 million square miles (29.9 million square km) in 2000.
On the Earth”s surface, ozone is a pollutant, but in the stratosphere, it reflects ultraviolet radiation back into space, protecting us from skin cancer-causing UV rays.
Scientists say the hole in this protective ozone layer mainly is caused by chlorine from man-made chemicals called chlorofluorocarbons (CFCs), which were created in the early 20th century and used in products like spray cans. CFCs, which destroy ozone, are believed to linger in the stratosphere for decades.
Air temperature can affect the rate at which these CFCs break apart ozone molecules. Years with large ozone holes are generally associated with very cold winters over Antarctica and high polar winds, the scientists say.
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