LETTERS: GLOBAL WARMING IMPORTANT TO ALL

To the editor:

Several years ago someone told me that I should present the weather as if I were talking to my mom. This was supposed to reduce stage fright while at the same time slowing my delivery. All in all, I feel the advice has worked, though I sometimes still feel like I should go to my room when I've missed a forecast.

Reading the debate in the editorial pages on the subject of global warming brings to mind the same sort of advice. Lots of seemingly contradictory facts and opinions are being tossed about, with the net result, I suspect, of causing most of us to duck our heads and hope that someone somewhere makes the right decisions. Yet the subject of global warming is an important one that is likely to affect all of us, because we are all in some way probably part of the problem.

There are two parts to the global-warming debate. One part is somewhat controversial, the other part less so. The controversial part has to do with whether global warming is already occurring. To quote from the American Meteorological Society, "Observations suggest, but are insufficient to prove, that atmospheric warming caused by human activity has already occurred." Worldwide temperature records do seem to indicate a slight warming over the last century. But there is debate among respected scientists. If the atmosphere is warming, is it do to human activity or just a naturally occurring variation or a combination of the two? Recent evidence, such as longer growing seasons and melting ice sheets at the poles, seems to be tipping the balance in favor of the human factor. And word that 1997 turned out to be the warmest year on record finally prompted a senior scientist with the National Oceanic and Atmospheric Administration to say that there is now evidence of global warming, "at least some of which is attributable to human activities." The debate continues.

Less controversial is the question as to whether global warming will occur in the future. The science is pretty simple: You add enough so-called greenhouse gases to the atmosphere, and things heat up. These gases, like methane and carbon dioxide, do come from a variety of sources, but most scientists agree that the increases currently being measured result mainly from human activities, like burning fossil fuels and cutting down tropical forests. Computer simulations show that a continued increase in these greenhouse gases would likely cause an overall warming of several degrees over the next century. The problem is that these simulations, or models, although constantly being improved are still nowhere near as complex as the real earth-atmosphere system. For example, the role of clouds -- critical to how the atmosphere reflects, absorbs or creates heat -- is still poorly understood.

In fact, there are a few scientists who feel that there may be enough balancing factors like cloud formation, plant growth or ocean currents that global warming will not be a serious problem. Others fear that different feedback mechanisms could actually make things worse. Overall, most scientists agree that the evidence shows a "reasonable probability for large climate changes over the impending decades" (again quoting from the American Meteorological Society).

The most difficult thing may be deciding whether the threat posed by global warming justifies making significant and perhaps costly changes in our present lifestyles. Naturally, we tend to think near-term. We're more worried about the weather tomorrow than the climate 50 years from now. Yet is seems unfair to burden our grandchildren with serious economic and environmental problems merely because we didn't feel like making a few sacrifices. Of course, as the climate models and the computers that run them continue to improve over the coming years, we'll have a better idea of when and how much the climate may change. The danger is that the longer we wait to take action, the more difficult and expensive that action may be.

BRIAN ALWORTH

Cape Girardeau