First set your policy, then find the evidence. That traditional scientific method.
A great line from Ben Pile over at Climate Resistance when he was looking at the IPCC's most recent report back in May. He goes through the authors of the report and notes that they are al part of the bureacracy of Renewable/para-governmental/lobbyist community that populates the IPCC and its cohorts.
Meanwhile Steve McIntyre at Climate audit has noticed a slight problem with the report's introduction/conclusions, in that they were pre-written by Greenpeace and a Brussels based body namely EREC, the European Renewable Energy Council.
I am sure there may be a teensey little bit of public money floating around this august organisation.