Observational constraints on the cloud feedback pattern effect

October 06, 2022

Tim Myers

Hosted by Dave Randall

Abstract

Historically, the response of clouds to planetary warming has been among the most uncertain of all climate feedbacks. In this seminar, I highlight advances in observational methods that have substantially reduced this uncertainty. Recent observational evidence stemming from the framework of cloud-controlling factor analysis suggests that, in response to increasing CO2, low clouds over the global oceans exert a positive feedback to warming. I also provide observational evidence for a strong time-dependence of the marine cloud feedback over the last ~100 years, driven by fluctuating sea-surface temperature patterns and associated meteorological perturbations. From 1980 to near-present, increasing estimated inversion strength produced a negative cloud feedback to planetary warming, opposite to the positive feedback expected from increasing CO2. This indicates that the processes responsible for marine cloud changes in recent decades are distinct from those associated with an increase in CO2.