The term used by the Intergovernmental Panel on Climate Change (IPCC) to express the relationship between human-caused emissions that add to the Earth’s greenhouse effect — carbon dioxide along with other greenhouse gases — and the temperature changes that will result from these emissions. Specifically, it is the average global air surface temperature change resulting from a doubling of pre-industrial atmospheric CO2 concentrations. The most recent IPCC estimate for climate sensitivity ranges from 2 to 3.5 degrees celsius.