One of the disturbing aspects of the AGW hypothesis is the creation of the temperature history of earth. A lot of cretivity has gone into this key aspect of showing that there has recently been unprecedented warming. A lot of people with no involvement in the debate (which never actually happened) have had questions about the past temperature record, which has been generated with a lot af adjustment to the raw record. One disturbing aspect has been the reluctance of the various authors to share data, and the fact that peer review of papers did not include examination of the data. Researchers like those at NASA/GISS contiually revise the temperature record, with all of the changes going in the direction of supporting the AGW hypothesis, as unlikely as this should be statistically. This has been a red flag for a lot of scientists. The IPCC procedures in particular did not follow the accepted scientific method. Now there are some allegations of outright fraud. Here is an example:

http://freebornjohn.blogspot.com/2008/06/climate-fraud-allegations.html