Destruction of ozone over the Antarctic appeared to level out this year, but a U.N. scientist warned Wednesday it could get worse in years to come.
Ozone gas plays a key role in shielding people, animals and plants from dangerous forms of ultraviolet radiation. Its depletion, caused in large part by industrial chemicals, is believed to increase the incidence of skin cancer and cataracts.
A seasonal hole in the ozone layer, first observed in the Antarctic in the 1980s, has reappeared each year since then.
The year’s ozone loss is “comparable to the previous record-setting years,” said Dr. Rumen Bojkov, the World Meteorological Organization’s adviser on ozone. The gas is almost completely gone from an atmospheric level between 5.4 miles and 14 miles above the earth, he said.
The hole - nearly as large as North America - remained steady in surface area during the Antarctic spring, when atmospheric conditions combine to produce maximum ozone destruction.
The hole’s area fell just short of the record size set last year of 7.7 million square miles, but the weather agency said the difference was not significant.
Ozone loss should peak between 2001 and 2005 if countries abide by agreements to cut back on use of man-made chemicals, Bojkov said. A 1987 pact called for 50-percent reduction of ozone-damaging chlorofluorocarbons by 2000.
“But in the next 10 to 15 years, when the ozone destructive chemical concentrations in stratosphere will be at their highest point, any single year depending on favorable atmospheric conditions … could produce a rapid ozone destruction of even more than the numbers we have noted,” Bojkov cautioned.
He noted that Antarctic measurements are a bellwether, indicating the extent of ozone loss in the middle latitudes - the stratosphere covering the most populated areas, including the United States.
The United States and England, for example, have lost between 12 and 14 percent of their ozone layer in the past few decades, he said.
While the worst situation has been developing over the South Pole, there also have been signs of danger over the North Pole. The ozone layer is thinning over the Arctic during the Northern Hemisphere’s winter, and scientists say that if the trend continues, it could soon develop into an ozone hole over that region as well.