Encouraging report on ozone restoration
WASHINGTON — Earth’s protective ozone layer is finally healing from damage caused by aerosol sprays and coolants, according to a new report from the United Nations.
The ozone layer had been thinning since the late 1970s. Scientist raised the alarm and ozone-depleting chemicals were phased out worldwide.
As a result, the upper ozone layer above the Northern Hemisphere should be completely repaired in the 2030s and the gaping 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 report co-chairman Paul Newman, chief Earth 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 that cause skin cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, began eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses came up with replacements for spray cans and other uses.
At its worst in the late 1990s, about 10 percent of the upper ozone layer was depleted, said Newman. Since 2000, it has increased by about 1 to 3 percent per decade, the report said.
This year, the ozone hole over the South Pole peaked at nearly 9.6 million square miles. That’s about 16 percent smaller than the biggest hole recorded — 11.4 million square miles in 2006.
The hole reaches its peak in September and October and disappears by late December until the next Southern Hemisphere spring, Newman said.
The ozone layer starts at about 6 miles above Earth and stretches for nearly 25 miles; ozone is a colorless combination of three oxygen atoms.
If nothing had been done to stop the thinning, the world would have destroyed twothirds of its ozone layer by 2065, Newman said.
“I don’t think we can do a victory lap until 2060,” Newman said. “That will be for our grandchildren to do.”