Today's WSJ has a neat op-ed by Bjorn Lomborg about Al Gore declining to debate him, because Lomborg has "been very critical of Mr. Gore's message about global warming and has questioned Mr. Gore's evenhandedness"! My local paper recently announced that Exxon should be prevented from funding Global Warming skeptic research. The debate on Global Warming is pretty one-sided, as skeptics are generally considered mere shills for industry, not worthy consideration, even criminal perhaps.

I'm skeptical of Global Warming for a variety of reasons, and understand the consensus as an example of a "larger truth" guiding the little truths (see good empirical issues raised by Art Robinson or the CEI). That larger truth is that those who think that the market needs more state regulation and less automation, global warming is a Gaia-send. The simple peasant life has been romanticized since the first industrial revolution, even though mortality and violent death rates back then were several times what they are today. In the face of the dislocations brought on by capitalism and global competition, many long for a return to the simplicity and wholeness of a life attuned to nature's purity, where in nature--as opposed to human society--there is a necessary connectedness where all things are equally important, be they shrub, worm, animal. People have a strong natural inclination to believe in Original Sin, so we think humans, as opposed to animals, are somehow unnatural and thus less good. A beaver dam or termite mound is beautiful, a shopping mall an abomination.

What makes me reflexively take the other side is that I can't really think of a case where the public and intelligentsia were in such agreement on a complicated theory that turned out to be true. Consider the unanimity of belief that Global Warming is 1) anthropogenic, 2) a net bad for humanity and 3) best solved by slowing developed country growth in various ways. I can't think of any proposition in economics with this kind of unanimity. For example: demand curves slope down, right? Well, not necessarily for labor, apparently, as many think employment demand will be unaffected by raising the minimum wage. So it scares me that so many people, experts and non-experts, agree on something as complicated and multi-faceted as Global Warming. It strongly suggests there is something more than "the facts" at play, because mere facts aren't that persuasive--never have been, never will.

An analogous scientific consensus was the belief that nuclear testing caused millions of cancer deaths, popularized by scientific heavyweight Linus Pauling. High levels of radiation will certainly kill you, and lower levels will harm you. Linus Pauling calculated the damage at minuscule levels by extending that graph back in a straight line to zero. Zero radiation, obviously, causes no harm. At low levels not many would be harmed, but multiplying that low level by the population of the world, as Pauling did, allowed him to claim that continued nuclear testing would kill millions of children. So it should be stopped. Pauling organized a petition against nuclear testing signed by 11,000 scientists and presented to the United Nations, for which he won the Nobel Peace Prize (to add to his Nobel in chemistry). It was all science and logic. Naysayers were anti-scientific ideologues. But with poisons dosage is key, and highly nonlinear. The graph of radiation mortality does not go straight back to zero. It goes down to about 700 millirems a day, then heads back up again, like a hook. Low background levels of radiation seem to be good for you. The evidence that the "linear extrapolation to zero" is wrong, in that while bad for you in large doses, radiation does some good in small doses. It seems to keep the DNA repair mechanisms in good working order. The same principle is observed with alcohol, a potential poison: heavy drinking will kill you, but a glass of wine a day is good for you.

Theories that are really compelling are often wrong, because all theories are simplifications to a more complicated reality. So the fact that 90% of the population believe X causes Y and can be fixed by Z makes me highly skeptical. When in history has something complicated, true, and important, been so agreed upon prior to definitive evidence? It suggests the facts have little to do with it.