Arctic climate sensitivity simulated with the CCSM2: Local and remote effects on feedback processes

Positive feedbacks unique to the polar regions are thought to render the Arctic particularly sensitive to anthropogenic climate forcing. Many global models simulate increased heat and moisture transport into the high northern latitudes when subject to a increase in greenhouse gas levels. In most of these simulations the transports increase mainly during spring and summer, when the ice albedo feedback mechanism is operating. We investigate climate sensitivity and feedbacks in the Arctic climate system in response to local radiative forcing and the remote influences from changes in heat and moisture transport using the Community Climate System Model (CCSM). Global climate simulations with the CCSM that are subject to transient increases in greenhouse gases automatically include both local and remote influences in the high latitudes. We use a single column version of the CCSM to test the response of the Arctic climate individually to local and remote forcings from the global model.