The president vowed to make climate change a top priority in his second term, suggesting that a major assault on industry is coming if he is re-elected.  So before the potential onslaught, some real-world perspective on climate change is essential.

First, note that the tool used to both develop future global climate scenarios and to panic the public on meteorological mayhem is atmospheric modeling.

Most of my nearly 35 years of professional life has been involved with atmospheric modeling in one way or another.  I began my scientific career in meteorology in the late '70s.  Back then, calculating air quality impacts of air pollution sources, such as smokestacks and vents, involved using a simple statistical calculator and some basic graphs derived from empirical studies -- a rudimentary form of modeling.

Over the years, with more powerful computers and sophisticated graphics, air pollution meteorologists, like me, were able to analyze in more depth and with finer detail contaminant concentrations as they spread from their emission locations.

Today, air-quality models are coupled with some of the very same meteorological models used in climate studies.  In this way, state-of-the-science estimates can be made to determine whether, for instance, a proposed industrial facility will contribute to unacceptable deterioration of air quality.

Air pollution models have long been used to evaluate just about any significant operation from the smallest chemical plant to the largest nuclear or coal-fired power plant.  Furthermore, the models are useful in anticipating the consequences of mundane releases of contaminants to catastrophic outbursts from accidents or terrorist attacks that disperse gases or particles like chlorine dioxide or anthrax.

What I and so many other air modelers have discovered is that, as impressive as modeling has become, model results beyond the immediate downwind distance of the pollution source and within a relatively brief amount of time, are not very reliable, despite the awesome computing power available today.  We know that dependence on their output is quite limited and to extrapolate too far beyond the bounds of the model assumptions is foolhardy.

Compare the experience of thousands of non-academic air modelers with the largely academic and government climate modelers.  Their combined efforts have produced impressive results in scope and scale, yet, like air pollution modeling, their model outputs for long-term global climate conditions still boil down to limited guesses.

Regardless, a bit of understanding about the global atmosphere has been spun into a trillion-dollar bonanza by a colaition of supporters.  These cheerleaders take the form of career politicians, bureaucrats, environmental and social activists, academics and educators, technologists and consultants, journalists, bloggers, and groupies of all stripes.

But realism and humility about the limitations of climate modeling must set in soon with enough scientists and those of the general public who care enough to pay attention.  Let's face it: if Mr. Obama gets his way in November, then more than our supposed climate future with be in dire straits.

Meteorologist Anthony J. Sadar is the author of In Global Warming We Trust: A Heretic's Guide to Climate Science (Telescope Books: www.telescopebooks.com).