Earth’s ozone hole shrivels to smallest since 1988

WASHINGTON – The ozone hole over Antarctica shrank to its smallest peak since 1988, the National Aeronautics and Space Administration (NASA) disclosed on Thursday.

The huge hole in Earth’s protective ozone layer reached its maximum last September, and this year NASA said it was 7.6 million square miles wide or 19.6 million square kilometers. The size of the ozone hole dwindled after mid-September.

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, according to NASA.

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 have nOt 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.

Newman said this year’s drop is mostly natural but is on top of a trend of smaller steady improvements likely from the banning of ozone-eating chemicals through the Montreal Protocol on Substances that Deplete the Ozone Layer. The ozone hole hit its highest in 2000 at 11.5 million square miles or 29.86 million square kilometers.

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

A few years back, scientists at the United Nations (UN) determined that without the Montreal Protocol on Substances that Deplete the Ozone Layer there would have been an extra 2 million skin cancer cases by 2030. Scientists said that overall the ozone layer is beginning to recover because of the phase-out of chemicals used in refrigerants and aerosol cans.

The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by gradually eliminating the production and use of numerous substances that harm the ozone and eventually cause its depletion. The UN treaty was agreed on by member-states on September 16, 1987. It entered into force on January 1, 1989. /kga