Environmental activists, aided and abetted by an uncritical press and sensationalist TV specials, have promoted a global warming scare. They base their campaign on a supposed scientific con- sensus: namely that the continued emission of carbon dioxide from the burning of oil, gas and coal enhances the natural atmospheric "greenhouse" effect and inevitably leads to a catastrophic temperature increase in the next century. A just completed survey of climate experts, however, shows no such consensus and demolishes the whole notion that energy use must be drastically constrained to avert a hypothetical climate disaster.

The myth of scientific consensus got a major boost last summer with the release of "Scientific Assessment of Climate Change," published by the Intergovernmental Panel on Climate Change. The IPCC started as a group of largely self-appointed environmental activists, garnered governmental and United Nations support, and enlisted some 170 climate scientists from around the world into contributing to its report.

But shortly after the release of the IPCC report, some of its scientific contributors expressed disagreement with it—particularly with its much-publicized, non-technical summary. It was this summary, written by a small IPCC steering group, that was presented to politicians and the public as an "authoritative statement of the International scientific community" that greenhouse warming posed a major environmental threat.

Because the IPCC summary has figured so prominently in the current policy debate over greenhouse warming, my colleague, Jay Winston, and I decided to survey the IPCC contributors (who wrote the chapter drafts) and reviewers (who commented on those drafts) to gauge their views independently. (Mr. Winston is the former director of the Climate Analysis Center of the National Weather Service.)

The survey, conducted this summer comprised nearly all of the American IPCC participants and separately, as a comparison group, some equally distinguished atmospheric scientists who had been excluded from the IPCC process perhaps because their writings had evidenced a skeptical attitude about greenhouse warming. This comparison group primarily academics from MIT, the University of Virginia, and other well-known institutions—had met in Phoenix, Ariz., last October to plan a scientific research program to tackle outstanding questions surrounding global climate change.

In all, questionnaires were sent to 126 scientists. The 31 IPCC reviewers and the 24-member Phoenix group showed a nearly 60% response rate; more than 20% of the 71 IPCC contributors responded to the survey. (While the contributors and reviewers were grouped together in the analysis that follows, we noted a statistically significant difference between the viewpoints of the contributors and the reviewers, with the former holding views closer to those of the skeptical Phoenix group.)

>The responses failed to show consensus on the effect of greenhouse warming: Some 40% of the IPCC group did not agree with the IPCC summary; half of that group, and nearly all of the Phoenix group, also believed that the summary might convey a misleading message to the public. (This refers specifically to the summary's prominently displayed conclusion of "certainty" about the natural greenhouse effect—a fact no one disputes. It is equivalent to revealing, in hushed tones, that the Earth is round.)

The issue, of course, is whether the man-made enhancements to natural atmospheric greenhouse gases have had an identifiable climate effect so far:

• Nearly all of the IPCC group agreed with the key IPCC conclusion, buried on page 254 of the report, that "it is not possible to attribute all, or even a large part, of the observed global-mean warming [of 0.5 degree Celsius since 1890] to the enhanced greenhouse effect on the basis of observational data currently available."

• On the question of future warming, virtually all of the IPCC participants agreed with the Phoenix group that the various theoretical models currently used for climate prediction—similar in many respects to the models used for long-range weather forecasting—have not been adequately validated by the existing climate record. (This means that if we go back to say, the year 1890 and apply the theory, it fails to predict the observed climate pattern that actually occurred.)

• Furthermore, 60% of the IPCC group, and all of the Phoenix group, believed that the current global circulation models do not accurately portray the real atmosphere-ocean system. Yet these models form the only basis for predicting a catastrophic warming in the next century.

  As the survey results indicate, scientists are not marching in intellectual lock-step on the major scientific issues that underlie the global warming scare. Within the scientific community itself, this lack of consensus-indeed, the raging debate-has been well known. Witness the lead editorial in the March 31, 1990, issue of Science by Philip Abelson, one of its editors: ". . . if the Iglobal warming] situation is analyzed applying the customary standards of scientific inquiry one must conclude that there has been more hype than solid fact."

  But it has been difficult for skeptics to make their voices heard before the general public. For example, the British TV documentary "The Greenhouse Conspiracy," a highly critical but balanced scientific discussion shown on the BBC last year, has been stonewalled by PBS. Yet public television has never hesitated to broadcast such shamelessly one-sided scare pieces as "Crisis in the Atmosphere" and "After the Warming."

  Perhaps encouraged by the 1987 Montreal Protocol, which resulted in an international agreement to phase out chlorofluorocarbons, the activists are flow looking to the June 1992 U.N. Conference on Environment and Development in Rio de Janeiro to do a similar job on carbon dioxide and energy generation.

  The economic stakes are much higher here. The notion of a climate disaster has been widely propagated by those who want to impose controls on the emission of carbon dioxide, thereby severely limiting the use of energy and, in consequence, economic growth. To be effective, these wildly expensive constraints must be applied globally, condemning most of the world's population to a life of continued poverty. Even if it were backed by clear scientific data, the morality of such ecological imperialism is open to question.