The report assesses the current scientific knowledge on climate change, and documents its observed impacts. The third working group report on mitigation looks at mitigation strategies across a number of different sectors. It concludes that there is substantial economic potential for the mitigation of global greenhouse gas emissions that could offset the projected growth of global emissions or reduce emissions below current levels.
The report estimates that the stabilisation of greenhouse gas concentrations between 445ppm and 535ppm would cost less than 3% of global GDP. It also asserts however that there is much evidence that a substantial fraction of these mitigation costs could be offset by benefits such as increased energy security, improved public health, increased agricultural production and reduced pressure on natural ecosystems.