CMCC Seminar
May 16th at 14:00 in the meeting room BP-2B (Viale Berti Pichat 6/2, second floor).
Speaker:
Jeffrey Weiss from the Department of Atmospheric and Oceanic Science University of Colorado, Boulder
Anthropogenic warming is often summarized by a single number: the equilibrium climate sensitivity (ECS). Despite intense efforts, the uncertainty in ECS has remained undiminished and today’s best estimate for ECS is roughly unchanged from the estimate in the Charney report (1979): ECS ~ 3K ± 1.5K. The ECS uncertainty is usually attributed to the difficulties in resolving small scale convection. Here we turn to simple energy balance models (EBMs) in order to gain insight into the processes that determine the global average temperature of a planet. We explore how the pattern of meridional heat transport impacts the climate in a simple EBM. We find that regardless of the transport, there is a maximum average temperature. Furthermore, sharp transport gradients can cool the average temperature and in extreme cases can give climates where the average temperature equal to 0K while conserving energy. We speculate that this process might explain recent findings that some Earth System Models erroneously evolve to snowball Earth states. We also propose a new EBM with a simple parameterization of tropical convection to explore how convection impacts global average temperatures.
The seminar will also be available on Teams using the following link:
https://teams.microsoft.com/l/