Why is the scientific consensus on Anthropomorphic Global Warming (AGW) different than the scientific consensus on Evolution? Let me list some of the ways:
- Evolution has many independent, very different, lines of evidence (fossils, embryology, immunology, molecular biology, paleontology, etc...). AGW has at best 50-100 different data sets, from the dozen or so tree rings, to the dozen or so ice cores, satellite and surface temperature records. Much of our inference comes from computer simulations, that a very few completely understand. Much of global warming consensus comes from a small minority that are directly involved with the data or the simulations.
- We can control aspects of evolution. With knowledge of DNA, we can make genetically modified foods, we can change the course of diseases, and breed bacteria to eat nylon. Our understanding of AGW is at such a low level that we can only possibly control the climate at the grossest level. Our lack of understanding of feedback loops prevents even the most basic possible control of the system.
- Although evolution occurs on long time scales, we can see its action on the small scale. AGW also occurs on longish time scales, but there is no short-term equivalent. This adds to our level of control (with evolution), or lack of it with AGW.
- Those that are denying evolution want to replace it with something that violates not just evolution, but all of physics, chemistry, astronomy...pretty much all of science. Although the extremists in the anti-global warming camp can seem pretty anti-science, they aren't trying to replace global warming with something that violates all of science (they still might be wrong!). There is also a much more nuanced camp that admits that the planet is warmer, but perhaps it is not as special as the AGW theory would suggest, and that draconian CO2 policies are unwarranted given the uncertainties. This puts it on a very different scale than the anti-evolution group.
It is dangerous to make the comparison. One is partly the demonizing of your opponent and, at the same time, angelizing (is that a word? :) ) ones own perspective: by saying that the AGW deniers are just like the evolution deniers, both makes the deniers seem unreasonable, but by association, implies that AGW is as solid as evolution. This latter claim, despite the claims of its proponents, is definitely hyperbole.