Joint Seminar: Accounting for Uncertainty of Projected Sea Surface Temperature Patterns in Coupled Global Circulation Models

Temperature projections from atmosphere-ocean general circulation models (AOGCMs)—ubiquitously used for climate change decision making—do not account for the inability of AOGCMs to reproduce observed sea surface temperature (SST) patterns and trends. We refer to this deficiency as SST pattern uncertainty.  The effects of SST pattern uncertainty are amplified by the pattern effect, which states that SST changes in some oceanic regions more efficiently modify the global-mean radiative feedback parameter and thus global-mean temperature response than in other oceanic regions.  Here, we consider the relevance of SST pattern uncertainty to global-mean temperature projections through convolving radiation and surface temperature Green’s functions with physically plausible SST pattern scenarios.  SST pattern uncertainty has a significant impact on temperature projection uncertainty, for example by widening the uncertainty of warming in 2085 to 2.0K from an original uncertainty of 1.1K due to internal variability.  Furthermore, SST pattern uncertainty could explain future periods of weaker or stronger warming than projected by AOGCMs when starting from the observed SST pattern.  It is critical for climate change impact, adaptation, and mitigation assessments to incorporate this so far unaccounted for uncertainty in their projections of climate change until we thoroughly trust the forced and unforced evolution of surface warming patterns in AOGCMs. 

Date

31.08.2022

Time

13:30–14:30 h

Place

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Speaker

Marc Alessi, Colorado State University

Organizers

Chetankumar Jalihal
Swantje Bastin

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