I enjoyed this clip by John Stewart in retort to the climate change skeptics. That Vancouver is experiencing lower than average snowfall should make people question the rationale behind the DC snowstorm disproving global warming.
Seriously though, pointing out that a climate change denier is being irrational or thoughtless probably won't change his opinion (I've tried). When discussing this subject now, I frame the debate within the rubric of making our economy more efficient, healthy (less coal smog=less asthma), and less reliant on foreign energy. These are all things that can save us money by putting a price on the negative externalities (that are essentially subsidized by the US taxpayer). This line of reasoning does not always work, but they are themes that both skeptics and alarmists can usually agree on. The environmentalist movement needs to change its messaging if it is going to be successful. Josh Dorfman, a professional Green communication pundit speaks well to it here.
I enjoy John Stewart's digs at climate change naysayers as much as the next guy, but behind the sarcasm lies genuine frustration. I hope that as the science behind climate change solidifies, the skeptics will soften their positions and Stewart will have less reason to call them out.