This Times Online profile of Bjorn Lomborg, author of The Skeptical Environmentalist, is interesting in a couple of ways. One is that Lomborg drew enormous fire from environmentalists and climate scientists for his work challenging the numbers behind most global warming scenarios, but he has persevered. Right or wrong, he remains a voice challenging the current majority view. That is as necessary for good science as it is for good government. The other is that he advocates policies that result in net contributions to the welfare of people over those that sound good but don't end up changing behavior - and he puts most responses to global warming in that category.
I'm no expert on climate change or the degree to which it's human-caused, but I try to point out a couple of things. One is that this situation is incredibly complex and doesn't translate accurately to the kind of simplified presentation shown in An Inconvenient Truth. The other is that sincere dissent should not be criminalized - which some environmentalists have demanded, literally, for global warming skeptics.