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But the schedule now seems far too leisurely. Last week's grim news spurred new public warnings and calls for faster action. In Denmark an Environment Ministry spokesman went on television to urge fellow Danes not to panic -- but to use hats and sunscreen. German Environment Minister Klaus Topfer called on & other countries to match Germany's pledge to stop CFC production by 1995. Greenpeace activists in Britain met with Prime Minister John Major and implored him to halt the manufacture of all CFCs immediately.
The U.S. Congress passed a law in 1990 that called for an accelerated phaseout of CFCs if new scientific evidence revealed a greater threat to ozone than expected. Last week the Senate, by a 96-0 vote, found the evidence alarming enough to justify a faster phaseout. "Now that there's the prospect of a hole over Kennebunkport," Senator Al Gore said, "perhaps Bush will comply with the law." William Reilly, administrator of the Environmental Protection Agency, said that the U.S. might seek to end CFC production as early as 1996.
The vital gas being destroyed is a form of oxygen in which the molecules have three atoms instead of the normal two. That simple structure enables ozone to absorb ultraviolet radiation -- a process that is crucial to human health. UV rays can make the lens of the eye cloud up with cataracts, which bring on blindness if untreated. The radiation can cause mutations in DNA, leading to skin cancers, including the often deadly melanoma. Estimates released last week by the United Nations Environment Program predict a 26% rise in the incidence of nonmelanoma skin cancers worldwide if overall ozone levels drop 10%.
Excess UV radiation may also affect the body's general ability to fight off disease. Says immunologist Margaret Kripke of the M.D. Anderson Cancer Center in Houston: "We already know that ultraviolet light can impair immunity to infectious diseases in animals. We know that there are immunological effects in humans, though we don't yet know their significance."
Just as worrisome is the threat to the world's food supply. High doses of UV radiation can reduce the yield of basic crops such as soybeans. UV-B, the most dangerous variety of ultraviolet, penetrates scores of meters below the surface of the oceans. There the radiation can kill phytoplankton (one-celled plants) and krill (tiny shrimplike animals), which are at the very bottom of the ocean food chain. Since these organisms, found in greatest concentrations in Antarctic waters, nourish larger fish, the ultimate consumers -- humans -- may face a maritime food shortage. Scientists believe the lower plants and animals can adapt to rising UV levels by developing UV-absorbing cell pigments. But that works only up to a point, and no one knows what that point is.
) The impact of ozone loss will be felt first in Antarctica, where levels of the gas have been severely depleted each spring for several years. Populations of marine organisms are not shrinking so far, but they have begun to produce UV-absorbing pigments. In Australia, scientists believe that crops of wheat, sorghum and peas have been affected, and health officials report a threefold rise in skin cancers. There are anecdotal reports of more cancer in Argentina too. While no increase in cancers or cataracts has shown up yet in Chile or New Zealand, experts note that these diseases can take years to develop.