I found this op-ed highly persuasive. It occurs to me that the global warming debate is not unlike the WMD-terrorist debate, except the sides are reversed. Accrding to Ron Suskind, Dick Cheney's "one percent doctrine" means that if there's a one percent chance that a terrorist could have access to a WMD, we must act as if it were a certainty - because the outcome, however unlikely, would be too disastrous to risk. On global warming, Gore expresses a not-too-dissimilar equation: if there's a small chance that human behavior could lead to environmental catastrophe, we should act as if it were a certainty - because waiting too long is too big a risk to take. Cheney wins because 9/11 provided stark evidence of the real risk we now face. Gore needs images of catastrophe to ramp up public demands for action. Hence the movie and Vanity Fair pictorials.
In both cases, however, the evidence is complicated and hard to pin down with absolute certainty. We know we are at much greater risk now from Islamist terror than we were a decade ago - but measuring how much, and where from specifically, is very hard. Equally, we know that global warming is real, but whether it has reached or will soon reach a dangerous tipping point is not a given. And in both cases, the entire argument rests a great deal on what we do not and cannot know. It seems to me prudent to take both risks seriously, but not so seriously that we abandon objective, empirical judgment. If such judgment had been in more evidence four years ago, the Iraq WMD intelligence debacle might have been avoided.
Likewise, with global warming. Take the fact that there is
"little disagreement that levels of carbon dioxide in the atmosphere have risen from about 280 parts per million by volume in the 19th century to about 387 ppmv today. Finally, there has been no question whatever that carbon dioxide is an infrared absorber (i.e., a greenhouse gas - albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed, assuming that the small observed increase was in fact due to increasing carbon dioxide rather than a natural fluctuation in the climate system. Although no cause for alarm rests on this issue, there has been an intense effort to claim that the theoretically expected contribution from additional carbon dioxide has actually been detected. Given that we do not understand the natural internal variability of climate change, this task is currently impossible.
What to do? A prudent attempt to rein in carbon dioxide emissions seems a no-brainer to me. A dollar rise in the gas tax would be the most effective way to achieve this. But Cheney also made an assumption Gore hasn't: the American public will only sign up if they have no sacrifice to make, or if others do their sacrifices for them. The political health of America in the coming years will be measured by how hard politicians are prepared to challenge that atttitude.