Planet Of The Year: Global Warming Feeling the Heat

For more than a decade, many scientists have warned that cars and factories are spewing enough gases into the atmosphere to heat up the earth in a greenhouse effect that could eventually produce disastrous climate changes. But until recently, the prophets of global warming garnered about as much attention as the religious zealots who insist that Armageddon is near. When Colorado Senator Timothy Wirth held congressional hearings on the greenhouse effect in the fall of 1987, the topic generated no heat at all. "We had a very, very distinguished panel," Wirth recalled at the TIME Environment Conference, "and who was in the cavernous hearing room? Six or seven people, and two or three of them were lost tourists."

So Wirth decided to schedule another hearing in the summer, hoping hot weather would make people pay attention to the greenhouse issue. Sure enough, when the hearing convened last June 23, the thermometer read 99 degrees F, a Washington record for that day. The room was packed when James Hansen, head of NASA's Goddard Institute for Space Studies, turned global warming into front- page news at last. "It is time to stop waffling so much," he declared. "The evidence is pretty strong that the greenhouse effect is here."

Hansen thus became perhaps the most prominent scientist willing to say straight out that the earth-warming effect of excess carbon dioxide (CO2) and other gases generated by industry and agriculture had crossed the line from theory into fact. By itself, Hansen's bold assertion was dramatic enough. But the unusual string of weather-related disasters that struck the world last summer could not have been better timed to drive his point home. The heat waves, droughts, floods and hurricanes may be previews of what could happen with ever increasing frequency if the atmosphere warms 3 degrees F to 8 degrees F by the middle of the next century, as some scientists predict.

On the other hand, the summer's disasters may have had nothing to do with the greenhouse effect. They could have been random events -- all part of the natural year-to-year variations in weather. Many climatologists called Hansen's remarks premature and feared that if this summer happens to be cool, public worries about the greenhouse effect will quickly fade.

Unfortunately, scientists cannot agree on how much global warming has occurred, how much more is on the way and what the climatic consequences will be, giving policymakers an excuse for delay. But no one disputes the fact that the amount of CO2 in the atmosphere has risen and continues to increase rapidly and that the human race is thus conducting a dangerous experiment on an unprecedented scale. The possible consequences are so scary that it is only prudent for governments to slow the buildup of CO2 through preventive measures, from encouraging energy conservation to developing alternatives to fossil fuels.