HR: 1340h
AN: U43A-0858    [Abstracts]
TI: Climate sensitivity to carbon emissions
AU: * Matthews, D
EM: dmatthew@alcor.concordia.ca
AF: Concordia University, 1455 de Maisonneuve Blvd W., Montreal, QC H3G 1M8, Canada
AB: Climate sensitivity defines the climate system response to an imposed radiative forcing, often characterized as the equilibrium temperature change in response to a doubling of atmospheric carbon dioxide. Climate sensitivity includes the direct effect of a change in forcing, in addition to the net effect of positive and negative climate feedbacks. However, the traditional concept of climate sensitivity is unable to accommodate carbon cycle feedbacks, which affect the level of carbon dioxide in the atmosphere directly, rather than the climate response to a given CO₂ level. Earth system models which include interactive carbon cycle components have shown that carbon cycle feedbacks can vary substantially between models, and that this adds an additional level of uncertainty to that described by climate sensitivity. In this study, I propose a new measure of climate response, which is referenced to carbon emissions, rather than concentrations. This quantity (the Emissions Climate Response, or ECR) includes the direct carbon cycle response to CO₂ emissions, the climate response to CO₂ concentrations, as well as any feedbacks between climate change and carbon sinks. Using an intermediate complexity Earth system model, I illustrate the concept of the ECR with reference to the more traditional quantities of equilibrium climate sensitivity and transient climate response. I also present a framework within which the total climate response can be separated into its component carbon cycle and climate sensitivities.
DE: 1600 GLOBAL CHANGE
DE: 1622 Earth system modeling (1225)
DE: 1626 Global climate models (3337, 4928)
SC: Union [U]
MN: 2007 Fall Meeting