Bishop Hill has a guest post by an anonymous "Lone Wolf" who claims to be a UK university professor. The post tells the tale of a student with whom the author worked examining the Vostok Ice Core, which is one of the longest datasets in paleoclimatology, reaching back 420,000 years. After the anonymous author and student presented their work at a small conference, the author was shocked at the negative response from academia.
The presented findings showed that past temperatures increased 200 to 1,000 years before CO2 concentrations increased, which Lone Wolf believes disproves the hypothesis of man-made global warming. Apparently the audience was not at all persuaded by the presentation and didn't hesitate to show it. When the conference later issued a newsletter summarizing the presentations, Lone Wolf was not included in the coverage.
While deniers say this snub from a newsletter is another example of alarmist suppression of skeptics, in reality it's an example of just how naive skeptics are about the basics of the carbon cycle. Lone Wolf even admits to approaching the topic from a "purely statistical point of view," saying "I am not a climatologist or bona fide weather expert."
Skeptical Science has a nice rebuttal to this well-worn claim if you're still curious. But the short answer is that a skeptic didn't know the basics of the carbon cycle and blamed academia when they tried to spare him or her the embarrassment of publishing a hopelessly naive presentation.