for National Geographic News
Running low on sunscreen? Lost your sunglasses? Better buy some more.
The gaping hole in the ozone layer above Antarctica may take 15 years longer to recover than anticipated, scientists warned Tuesday, adding that old refrigerators and cars may be to blame.
The ozone layer prevents harmful ultraviolet (UV) sunlight from reaching Earth. Without this protective layer, people are more susceptible to skin cancer and eye damage, scientists say.
UV rays may also harm wildlife, reduce crop yields, and kink the ocean food chain, research shows.
A hole in the ozone layer above Antarctica was first noted in scientific literature 20 years ago. Prior to those reports, scientists predicted chemicals such as chlorofluorocarbons (CFCs) used in refrigerators and car air conditioners would damage the ozone layer.
In 1987, two years after the ozone hole was detected, many nations around the world agreed under the Montreal Protocol to phase out the production of ozone-depleting chemicals. Doing so, scientists predicted, would enable the hole to recover by about 2050.
But new research presented Tuesday at the annual meeting of the American Geophysical Union in San Francisco, California, shows that the recovery may be delayed, perhaps until 2065.
Paul Newman, an atmospheric scientist at the NASA Goddard Space Flight Center in Greenbelt, Maryland, explained why: "We believed the U.S. was no longer emitting a significant amount of chlorofluorocarbon containing compounds. That's not the case."
Dale Hurst, an atmospheric chemist with the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, presented measurements taken in 2003 that show ozone-depleting chemicals are still emitted in the U.S. and Canada.
The measurements, taken from a low-flying aircraft, indicate that the U.S. and Canada are responsible for 7 to 45 percent of the global emissions of various ozone-depleting substances.
"This to us was a surprising result because these chemicals have not been produced in the U.S. or Canada since 1995. And when they were produced, they were typically released to the atmosphere within one to five years," Hurst said.
SOURCES AND RELATED WEB SITES