See this Wall Street Journal article for an in-depth and relatively technical preview of the soon-to-be-released Intergovernmental Panel on Climate Change report on climate change. The last such report came out in 2007; since that time our understanding of climate science has made great strides.
Matt Ridley's summary of the new findings suggests the Chicken Little cries of Al Gore and his claque have been seriously overstated. There is an argument that a mild increase in world temperature, say 2 degrees celsius, might be of net benefit for human beings.
