Word: ultraviolet
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...about 30 other nations were observers), was a historic improvement on the already tough Montreal Protocol of 1987. That pact called for a reduction by the end of the century in worldwide production of ozone-depleting CFCs and halons, man-made chemicals that allow ever increasing amounts of dangerous ultraviolet light to reach the earth's surface. But since Montreal, a consensus had been growing that mere limitation was not enough. All the participating nations agreed that both types of chemicals should be phased out almost entirely by century's end. Moreover, two other destructive chemicals, carbon tetrachloride and methyl...
...Severe restrictions on the use of chlorofluorocarbons (CFCs), which damage the atmosphere by destroying the stratospheric ozone layer that shields the earth from harmful ultraviolet radiation...
...analyzing the radiation, the instruments will translate it into electronic impulses and beam it down to earth at a prodigious rate -- fast enough to fill a 30-volume encyclopedia in 42 minutes. Moreover, the Hubble will literally view the stars in a new light: the space observatory can see ultraviolet radiation that fails to reach ground telescopes because it is largely blocked by the earth's ozone shield...
Since then, researchers have been monitoring the hole and looking for similar ozone destruction over populated areas. Scientists predict that thinning ozone, and the resulting increase in ultraviolet radiation, will cause damage to plants and animals, as well as skin cancers and cataracts in humans. To keep a bad situation from getting worse, nations are working on an international agreement designed to phase out production of CFCs by the year...
...meantime, researchers have been carefully studying the effects of ozone depletion on Antarctic life. Marine ecologist Sayed El-Sayed of Texas A& M University discovered two years ago at Palmer Station, a U.S. base on the Antarctic Peninsula, that high levels of ultraviolet damage the chlorophyll pigment vital for photosynthesis in phytoplankton, slowing the marine plants' growth rate by as much as 30%. That, in turn, could threaten krill, shrimplike creatures that feed on phytoplankton and are a key link in Antarctica's food chain. Says El-Sayed: "Fish, whales, penguins and winged birds all depend very heavily on krill...