On various climate blogs, there has been coverage recently about a climate change skeptic conference run by the American Heartland Institute. DeSmogBlog and Grist have been leading the scolding, though the mainstream media seems to have started to cotton on that these people are corrupt, frauds, or seriously misguided. The New York Times and Wall Street Journal both have pieces that are somewhat critical of the validity and motivation behind the conference.
You can argue all you like about what level of greenhouse gases in the atmosphere is represents a tolerable level of risk. You can likewise wade into many fascinating debates about paleoclimatology, climatic feedbacks, and technological development. Nobody has an especially good answer to the question of how climate change mitigation, development, and poverty reduction can be ethically balanced against one another. What you cannot do these days, while retaining your credibility, is deny that the human burning of fossil fuels is causing the planet to warm, and that the consequences of that warming are extremely likely to be harmful to human, plant, and animal life.
The whole thing reminds me of the laughable commercials produced by the Competitive Enterprise Institute. Here are some resources for countering the misguided or disingenuous arguments made by those who challenge the rigorously demonstrated elements of climate change science.