sorry it wasnt clear from my comment, but mainly that a governmental panel == politicized, and also that the IPCC reports to the UNFCCC, whose mission is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system". in other words, it assumes the hypothesis that the science should be testing
It's not a hypothesis. That greenhouse gases affect heat retention can and has been directly observed. That the rise in greenhouse gases is mostly human-induced can also be pretty directly shown by isotope analysis, which can distinguish CO2 that comes from burning fossil fuels or burning forests from other CO2 sources.
it's politicized in the other direction. the ipcc reports have to be approved by all the member countries, many of whom (like the good 'le USofA) really don't want to take action on climate change. this results in IPCC reports that are watered down. for example:
> Political influence on the IPCC has been documented by the release of a memo by ExxonMobil to the Bush administration, and its effects on the IPCC's leadership. The memo led to strong Bush administration lobbying, evidently at the behest of ExxonMobil, to oust Robert Watson, a climate scientist, from the IPCC chairmanship, and to have him replaced by Pachauri, who was seen at the time as more mild-mannered and industry-friendly.[142][143]