GLOBAL WARMING ANOTHER VIEWPOINT

"Anti Environmentalist President Increases Risk of Global Warming," the polemic by T.N. in the last spring issue of the Forum, contained many unsubstantiated assertions. I believe that his statements that "atmospheric scientists at NASA say that they are '99 percent certain"' global warming is occurring and that "the vast majority of scientists believe the global warming scenario to be probable, . . ." are questionable at best.

The chief proponent of the human-induced greenhouse effect is James Hansen at NASA's Goddard Institute for Space Studies. Dr. Hansen is an atmospheric modeler who bases his predictions upon the NASA atmospheric computer model, one of more than 20 different atmospheric computer models currently in vogue; each gives a different answer while using the same initial condP tions. Not one of the creators of these models claims that he or she can correctly predict the effect of clouds on the earth's climate or the effect of the interaction of ocean and atmosphere, a process occurring over the "vast majority" of the earth's surface. Dr. Hansen's model didn't even take this last effect into consideration, as he admits. There is currently a multinational effort underway to collect enough data to make some guesses at the mechanism of air-ocean interaction. On top of all of this is the fact that each model is chaotic by nature; i.e., if the initial information provided a model is chana,ed by a very, very small amount, its predictions diverge exponentially. This is the so-called butterfly effect in which an extra flap of a monarch's wing in Monterey today produces a decidedly different weather scenario for Europe a few years hence. It is true that under special conditions, a model's predictions using slightly different initial conditions may at first diverge and later converge toward similar solutions called "strange attractors." However, it is not at all clear that this convergent behavior is that which nature prefers. In other more common cases the solutions diverge wildly. This explains in part why no program can make reliable predictions of weather for more than a week or so in advance. The necessary "reality checks" that would help hone these climate models into viable scientific theories are, so-far, sparse or nonexistent.

Dr. Hansen started the greenhouse scare in 1988 when he test)fied before Congress with the purpose of securing more funding for atmospheric research. His testimony induded a terrifying scenario about global warming. He asserted that he was "99 percent certain" that the atmosphere would heat up noticeably before the end of 1988. As he spoke the average temperature of the earth started to nose-dive, and 1988 turned out to be one of the coolest years in recent decades. It happened because of the El Nino ocean current interacting with the atmosphere in the western Pacific. Not a single model had correctly pre&ted it.

T. also aoserts in hb article that the vast majority of scienffsts are convinced that human-induced global warming is underway. At least two years ago polls of scientists involved in atmospheric stu&s showed that only 15 percent to 20 percent were convinced that such warming was underway. Some 15 percent to 20 percent hardly constitutes a "vast majority." S. Fred Singer of the University of Virginia has publbhed an artkle, "Warming Theories Need Warning Labels," in The Bulletin of the Atomic Scientists (June 1992), pointing out that there is not scientific consensus that a global warming threat even exists.

Dr. Singer b the director of the Washington-based research group, Science and Environmental Policy Project (SEPP). In the summer of 1991 SEPP surveyed more than 120 U.S. atmospheric scientists, receiving more than 50 responses. Eighty-five percent agreed that there is not solid evidence that any greenhouse warming from human activity has occurred in the last century. Also, the respondents doubted the adequacy of the modds used to predict future changes in worldwide climate. In November 1991, a Gallup poll of 400 members of the American Meteorological Society and the American Geophydcal Union found only 19 percent believed that human activity may haue induced global warming within the last century.

Dr. Singer claims that, though most atmospheric scientists do not rule out the possibility (not probability) of some global warm ing, they believe that "catastrophic predictions are unsupported by the scientific evidence." It wDI take perhaps another decade of observations before we definitely know if warming is occurring. Indeed, many scientists and agricultural specialists believe that increased warmth and carbon dioxide may very well be beneficial to agricultural productivity. A statement signed by 50 atmospheric scientists warns that drastic steps to curtail carbon dioxide emissions could have "catastrophic" economic consequences that would fall most severely on developing countries and the poor. Perhaps the toothlessness of the Rio Earth Summit pact is a blessing in disguise.

Placing one's faith in unverified computer modeb is the last refuge of those who cannot be convincing otherwise. The disastrous use of computer modeling by the Pentagon in planning and executing the Vietnam war seems to hue been forgotten. Cur rently, the very people who condemn the use of science and technology as the bane of the world use one of its weakest finks, the unverified hypothesis, to justify their scare tactics. Rather than playing Chicken Little, we should make teaching respect for the environment and a rational understanding of environmental concems a cornerstone of our educational system. In the meantime, let us hope that the global warming scare, as has happened with nuclear winter and acid rain, will be dumped into the honey bucket of history.