Christopher Monckton wrote a quite long article for the Telegraph in which he tries to debunk the Stern report about global warming and Al Gore's Inconvenient Truth:
This week, I'll show how the UN undervalued the sun's effects on historical and contemporary climate, slashed the natural greenhouse effect, overstated the past century's temperature increase, repealed a fundamental law of physics and tripled the man-made greenhouse effect.
So to the scare. First, the UN implies that carbon dioxide ended the last four ice ages. It displays two 450,000-year graphs: a sawtooth curve of temperature and a sawtooth of airborne CO2 that's scaled to look similar. Usually, similar curves are superimposed for comparison. The UN didn't do that. If it had, the truth would have shown: the changes in temperature preceded the changes in CO2 levels.
You can read his article at The Telegraph, it also includes a 40-page PDF file with even more information. This story was also published on Slashdot a few days ago, it's pretty interesting to read their comment section, where several Slashdot readers debunk Monckton's debunkation.