Sponsored / Hosted by
Charlie Zender

Department Seminar: Jennifer Kay

Jennifer Kay
Associate Professor
Event Details

Title: How do clouds affect global warming?

Abstract: Understanding the influence of clouds on global warming remains an important unsolved research problem. Cloud feedbacks are often found to be the largest uncertainty in global warming projections from climate models. This talk presents an overview of this topic, with a focus on recent observations, theory, and modeling results. After a general introduction, experiments that disable cloud radiative feedbacks or “lock the clouds” within a state‐of‐the‐art and well‐documented climate model will be presented. Through comparison of idealized greenhouse experiments with and without cloud locking, the sign and magnitude of the influence of cloud feedbacks can be quantified. Global cloud feedbacks increase both global and Arctic warming by around 25%. In contrast, disabling Arctic cloud feedbacks has a negligible influence on both Arctic and global surface warming. Do observations and theory support a positive global cloud feedback and a weak Arctic cloud feedback?  What are the implications especially for greater-than-global Arctic warming?  Do global cooling experiments show equal-but-opposite results?

The Department of Earth System Science acknowledges our presence on the ancestral and unceded territory of the Acjachemen and Tongva peoples, who still hold strong cultural, spiritual and physical ties to this region.