text: By oversimplifying the climate story, it appears that the IPCC's projections are just straightforward physics: The 2 C to 6 C projected rise in global average temperature is the direct, linear result of increasing CO2. But in reality, the IPCC claims that CO2, acting alone, will result in only a 1.2 C rise in temperature. The rest depends on whether the climate amplifies (positive feedback) or diminishes (negative feedback) CO2 forcing.