The good folks at NOconsensus.org have put together a "report card" on The IPCC Fourth Assessment reports (AR4) where they have graded each Working Group on how many of the references in the reports cite peer-review studies. And they've created a wonderful graphic that summarizes their findings:
40 Citizen Auditors
5 Weeks Work
5600 Grey References
1 Discredited IPCC report.
I won't begin to address whether these "Citizen Auditors" were correct in their determination of what was "peer-reviewed" and what was not (since that would be immensely time consuming and therefore entirely impractical, which is what the good folks at NOconsensus.org are counting on). Nor will I address the fact that whether or not something is peer-reviewed does not directly mean the information cited is correct or incorrect (merely that it is sourced from a peer-reviewed journal). But just for sake of argument, what I will do is take their report at face value - that it is an accurate count of peer-reviewed vs. non-peer-reviewed references in the IPCC reports and that having less than 60% peer-reviewed constitutes an "F", etc.
NOconsensus.org was nice enough to sort their finding by ascending grade - starting with the F's and moving up to the A's. It is worth mentioning that the IPCC reports are published by three different Working Groups (WGs) that each address a different area of study - WG 1 covers the Scientific Basis, WG 2 covers Impacts, Adaptation and Vulnerability and WG 3 covers Mitigation. All of the hard science is in the WG 1 reports - this is where the Scientific Basis is established and all the science that shows that global warming is real and that it is primarily caused by human activities is presented.
I was able to take the data provided by NOconsensus.org and sort it by the associated working group. I was also able to calculate the number of peer-reviewed and non-peer-reviewed studies associated with each chapter using the percentages provided by NOLconsensus.org. Based on this, I was able to calculate that, according to Noconsensus.org, there are over 5,800 peer-reviewed studies that support the consensus view that global warming is real and that human activities are largely to blame. That's over 93% of the 6,226 studies referenced by WG 1, which is a solid "A" according to NOconsensus.org's grading scale. It is also significantly more than the dubious claims that some 450 peer-reviewed studies are supposedly skeptical of the consensus. That's over 12 times as many clearly in support vs. dubiously opposed. NOconsensus.org has done well in showing the strong consensus behind scientific basis of the theory of man-made global warming.
So congratulations IPCC on a job well done. And the next time anyone you talk to claims that there is no consensus on the scientific basis of climate change, just point them to this blog entry and tell them to send their congratulations on to the good folks at NOconsensus.org for helping to prove the overwhelming soundness of the science behind AGW theory.