Here’s a relatively short (26 min) video of a lecture by Michael Mann. I think it gives a very concise and accurate picture of the current science of climate change and the political attacks on climate scientists (Mann calls this the scientization of politics).
From the video description:
Michael E. Mann- Director of the Earth System Science Center gives a very eye-opening presentation at the 2012 Sustainable Operations Summit. Mann’s presentation highlighted themes from his most recent book: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. In his talk, Mann discussed the “Hockey Stick,” a graph he created with his colleagues to depict changes in Earth’s temperature dating back to 1000 AD. The graph was featured in the Summary for Policy Makers portion of the 2001 report of the Intergovernmental Panel on Climate Change (IPCC) and became an icon in the debate over human-caused climate change. Mann told the story behind the Hockey Stick, using it as a vehicle for exploring broader issues regarding the role of skepticism in science and the relationship between science and politics.