the hole truth

Hovering over Antarctica, the ozone hole covers 11.4 million square miles--an area more than three times the size of the United States. But at a climate conference in Buenos Aires last December, scientists announced an optimistic prediction: This huge rip in the atmosphere may actually seal itself up within the next 50 years. For years, scientists have been warning that the ozone hole has serious consequences for people and the environment. And indeed, skin cancer rates are significantly higher in ozone-depleted areas, like New Zealand, Chile and Argentina.

"In the long term, you will see the recovery of the ozone layer," says Richard McPeters, Ph.D., of NASA, "but it will take 20 to 30 years, maybe even 50 years, before we see the ozone levels returning to what they were like in the early 1980s." This prediction is based on the fact that atmospheric levels of chlorofluorocarbons (CFCs), the chemicals believed by scientists to be the prime culprit in ozone destruction, have been significantly reduced since their production was banned in 1987. Formerly used in aerosols, refrigerants and air conditioners, CFCs have been replaced by less harmful chemicals in recent years. Without the influx of new CFCs into the atmosphere, the ozone layer is slowly regenerating itself.

Don't throw away your SPF 30 sunscreen just yet, however. "All bets are off where the atmosphere is concerned," warns Kert Davies, a climate specialist with Greenpeace. "When they say the ozone hole is healing or getting normal, the question is, What is normal?" According to Davies, global warming has altered the chemical makeup of the lower atmosphere, making it very difficult to conclude when or if the ozone hole will close. In addition, he explains that greenhouse gasses being produced by automobiles and pesticides further deplete ozone.

Davies is most concerned about the effect of ozone depletion on phytoplankton in the Antarctic region. Without the protection of the ozone layer, high levels of ultraviolet light penetrate the atmosphere, killing phytoplankton, which are the primary source of food for shrimp and fish. In turn, the whales and other marine life that feed off the shrimp could suffer significant population losses. Conceivably, this could translate into a serious disruption of marine ecology. And, warns Davies, "if plant life is threatened, all life is threatened."

How many plant species provide 50 percent of the world's food supply?

a) 3 b) 30 c) 300

Answer: a) 3. Rice, corn and wheat.

--National Wildlife Federation

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