Environmental issues are vexing for three reasons: they carry heavy emotional baggage, they are scientifically and technically complex, and often they are important to our health and well-being. No other policy arena is so burdened. These attributes foster disingenuous arguments and even dishonesty.

Consider Stephen Schneider, a Stanford biologist and global warming alarmist, who argued in Discover magazine that sometimes scientists should distort the truth as a political strategy: "[W]e have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have…. Each of us has to decide what the right balance is between being effective and being honest."

We urge honesty.

Occasionally a situation, like climate change, serves as a "cutting gate," i.e., it divides people into two groups. We can learn a great deal by examining the sorting process. The publication of "The Skeptical Environmentalist" by Danish statistician Bjorn Lomborg exemplifies the problem. Green reaction is vicious condemnation. Others applaud Lomborg's analysis.

Consider him on climate change: "There is no doubt that mankind has influenced and is still increasing atmospheric concentrations of CO2 and that this will influence temperature. Yet we need to separate hyperbole from realities in order to choose our future optimally…. Global warming is important. Its total costs could be $5 trillion. Yet, our choices in dealing with global warming are also important…. Is it not curious, then, that the typical reporting on global warming tells us all the bad things that could happen from CO2 emissions, but few or none of the bad things that could come from overly zealous regulation of such emissions?"

This clearly is a balanced account. Yet he is savaged by Schneider's tribe. In January 2002, Scientific American ran a section titled, "Science Defends Itself Against 'The Skeptical Environmentalist.'" The editor asked "four leading experts" to critique Lomborg's treatment of their areas. The fix was in. The magazine chose writers known to detest Lomborg's thesis and refused to publish Lomborg's response. (Please read it at www.lomborg.com.)

The result was an embarrassment to an intellectually responsible magazine. As Philip Stott, a distinguished biogeography professor at the University of London, put it, "I have been involved in the editing of scientific journals for over 15 years, and I could never conceive of treating an author in the manner that the Scientific American has dealt with Dr. Lomborg."

As The Economist stated: "Science needs no defending from Mr. Lomborg. It may very well need defending from champions like Mr. Schneider."

Here's our explanation. When people discuss such issues they speak almost exclusively to kindred souls. This is natural; people seek confirmation of their beliefs by "experts." If they encounter adversarial positions, they are usually critiques by one's friends. Thus, alternative positions come predigested, distorted, and skewed by omission if not deliberate commission.

Thomas Schelling is one of the most distinguished economists of the past fifty years. He is a pioneer in the field of game theory, a founder of Harvard's Kennedy School of Government, and a member of the National Academy of Sciences.

For the last twenty-five years Schelling has examined climate change. Writing in Foreign Affairs, Schelling explains that even under worst-case forecasts, truly serious consequences of climate change are decades away. By then, those in the developing world will be much wealthier and more technologically adept. Schelling posits that the best climate-change policy is to emphasize continuous economic growth for the least well-off. Adopting costly short-term policies that seriously retard economic progress is terribly shortsighted. Why? Wealth dramatically increases resiliency, especially to climate change.

Schelling and other distinguished scholars offer serious policy analysis unbiased by ideology -- left, right, or Green. But Greens reflexively dismiss these messengers as pawns of business. Unable to break with politically correct but perverse policies, they slam serious alternative arguments. They are hyper-conservative, seeking climatic and ecological stasis.

Some elements of ecosystems will suffer from significant warming, for example white bark pine and mountain caribou, and we would mourn their displacement. But change, whether anthropogenic or natural, is inevitable. Our challenge is to deal with it responsibly. Silencing critics of conventional wisdom, cutting them into the pool of the disregarded, is an assault on science.