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Webinar: Through the Looking Glass: Forcing and Feedbacks in CESM2
Tuesday, 21 November 2017, 1:00
Tuesday, November 21, 2017. 1:00PM Eastern Time. Webinar: Through the Looking Glass: Forcing and Feedbacks in CESM2. Andrew Gettelman, NCAR. Sponsored by UCAR | Climate & Global Dynamics. More information here.
The combination of historical anthropogenic forcing with climate feedbacks determines the past trajectory of the climate system. The total historical and present anthropogenic forcing is uncertain, largely due to the anthropogenic aerosol influence on clouds. And the feedback response of the climate system to forcing is also uncertain. The result is large conceptual uncertainty in the total climate sensitivity and the future trajectory of the earth’s climate. The development of the Community Earth System Model version 2 (CESM2) has revealed several interesting sensitivities of the model to processes that govern both anthropogenic climate forcing and climate feedbacks. This occurred as the coupled configuration was being developed and several coupling issues worked out. This presentation will describe some of the pitfalls in the development process and illustrate the forcing and feedbacks in CESM2 (as they stand now) and ‘alternative’ versions of the model with different forcing and feedbacks, and put that in the context of what we can learn about using ‘emergent constraints’ from the present climate to falsify some of these possible versions of CESM2 that ‘might have been’.