Earth’s ozone hole shrinks to smallest since 1988

World
Europe

NASA said on Thursday that the ozone hole over Antarctica shrank to its smallest peak since 1988.

The huge hole in Earth’s protective ozone layer reached its maximum this year – 7.6 million square miles wide (19.6 million square kilometers) according to NASA – in September, which is when it reaches its peak.

This year’s maximum hole is more than twice as big as the United States, but it’s 1.3 million square miles less than last year and 3.3 million square miles smaller than 2015.

Paul Newman, chief Earth scientist at NASA’s Goddard Space Flight Center, said stormy conditions in the upper atmosphere warmed the air and kept chemicals chlorine and bromine from eating ozone. He said scientists haven’t quite figured out why some years are stormier, and have smaller ozone holes, than others.

“It’s really small this year. That’s a good thing,” Newman said.

Ozone depletion occurs in cold temperatures, so the ozone hole reaches its annual maximum in September or October, at the end of winter in the Southern Hemisphere. /NASA gif

Newman said this year’s drop is mostly natural but is part of a trend of smaller steady improvements, likely from the banning of ozone-eating chemicals in a 1987 international treaty. The ozone hole was its biggest in 2000 at 11.5 million square miles (29.86 million square kilometers).

Ozone is a colorless combination of three oxygen atoms. High in the atmosphere, about 7 to 25 miles (11 to 40 kilometers) above the Earth, ozone shields the Earth from ultraviolet rays that cause skin cancer, crop damage and other problems.

A few years ago, scientists at the United Nations determined that without the 1987 treaty, by 2030 there would have been an extra 2 million skin cancer cases.

Source(s): AP