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WASHINGTON (AP) – Earth's protective ozone layer is finally being removed from the United States.
The ozone layer had been thinning since the late 1970s. Scientists raised the alarm and ozone-depleting chemicals were phased out worldwide.
As a result, the upper ozone layer in the Northern Hemisphere should be completely repaired in the 2030s and the gap in Antarctic ozone hole should disappear in the 2060s, according to a scientific assessment released Monday at a conference in Quito, Ecuador. The Southern Hemisphere lags a bit and its ozone layer should be healed by mid-century.
"It's really good news," said Paul Newman, chief scientist at NASA's Goddard Space Flight Center. "If ozone-depleting substances had continued to increase, we would have seen huge effects. We stopped that. "
High in the atmosphere, ozone shields Earth from ultraviolet rays cause cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, started eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses with replacements for spray cans and other uses.
"At its worst in the late 1990s," said Newman, "about 10 percent of the ozone layer was depleted. Since 2000, it has increased by about 1 to 3 percent per decade, the report said.
This year, the ozone hole on the South Pole peaked at nearly 9.6 million square miles (24.8 million square kilometers). That's about 16 percent smaller than the biggest hole recorded – 11.4 million square miles in 2006.
Southern Hemisphere Spring, Newman said: "The hole reaches its peak in September and October and disappears by late.
The ozone layer starts at about 6 miles (10 kilometers) above Earth and stretches for nearly 25 miles (40 kilometers); Ozone is a colorless combination of three oxygen atoms.
If nothing had been done to stop the thinning, the world would have destroyed two-thirds of its ozone layer by 2065, Newman said.
But it's not a complete success yet, said University of Colorado Brian Toon, who was not part of the report.
"We are only at a point where recovery can be started," said Toon, pointing to some ozone measurements that have not yet increased.
Another problem is that new technology has been found in CFC out of East Asia, the report noted.
Ozone depleted, said Ross Salawitch, a University of Maryland atmospheric scientist who co-authored the ozone hole. the report.
So a healed ozone layer will worsen man-made climate change there a bit, Newman said.
Scientists do not know how much they are ozone-depleted, but they do not know how to do this, but they do not know how to do this, "it would be incredibly irresponsible not to do this," Salawitch said.
And the replacements are now being used to global warming, Newman said. An amendment to the Montreal Protocol that goes into effect next year.
"I do not think we can have a victory lap until 2060," Newman said. "That will be for our grandchildren to do."
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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