So much for consensus. - Global warming evangelists are wont to speak fervently about the "scientific consensus" in support of global warming. That there is an unwavering unanimity amongst researchers in regards to global warming is an interesting proposition, but one that must frequently yield to currently verifiable science. Given the contradictory research regarding the impact of anthropogenic greenhouse gases on global temperatures and the absence of sound predictive models, the threat of man-made global warming seems to represent coincidence masquerading as causation. It still remains unclear whether greenhouse gases are solely responsible for recently observed global climate changes. Scientists who have attempted to look at the earth’s climate over the last millennium have concluded that temperature fluctuations have been a part of the climatological history of the earth, and that significant climate change certainly occurred long before the development of the combustion engine.

The work of many other scientists suggests that our understanding of the water cycle and its impact of water vapor in the atmosphere is incomplete at best; when water vapor and other natural factors (e.g.: the carbon cycle) are included, man’s contribution to the overall greenhouse effect may yet be infinitesimal. At this point, any discussion of global warming beyond the context of the hypothetical is based more on faith in pseudo-scientific canon than in scientific fact. Moreover, the public’s opinion of the causes and seriousness of global warming are far from unanimous, as verified by a July 2006 Pew Research Center survey.

Roughly four-in-ten (41 percent) believe human activity such as burning fossil fuels is causing global warming, but just as many say either that global warming has been caused by natural patterns in the earth’s environment (21 percent), or that there is no solid evidence of global warming (20 percent).

The public also is divided over the gravity of the problem. While 41 percent say global warming is a very serious problem, 33 percent see it as somewhat serious and roughly a quarter (24 percent) think it is either not too serious or not a problem at all. Consequently, the issue ranks as a relatively low priority, well behind education, the economy, and the war in Iraq.

There is even some question as to whether certain types of pollution may actually help prevent global warming. This should not surprise, as scientists appear to have a minimal understanding of the cooling effects of such things as stratospheric ozone, airborne sulphates (so-called “white” aerosols that reflect solar radiation), organic carbons generated by the burning of fossil fuels, the indirect effects of volcanic aerosols (such as those emitted in the 1991 eruption of Mount Pinatubo in the Philippines) or the impact of the earth itself on concentrations of greenhouse gases (i.e.: the absorption or release of CO2 by soil and oceans.) Even the conversion of “green spaces” from forests to cropland has been shown to have a cooling effect on the climate. The potential cumulative impact of all of these influences could very well either potentiate or overcome any warming caused by greenhouse gases.

What we should be certain about is that when acolytes of global warming insist that a consensus exists, even in the presence of staggering scientific uncertainty, it is not their argument that is strengthened, but only our incredulity.