Quantifying AMOC Uncertainty in European Climate Damage Projections

Estimates of economic damages from climate change in Europe depend on temperature projections, and they are thereby subject to scenario uncertainty and model uncertainty, as well as damage function uncertainty. An additional, often implicit source of uncertainty is the projected, yet poorly constrained, weakening of the Atlantic Meridional Overturning Circulation (AMOC), which would lower European temperatures. Here, I explicitly quantify the contribution of AMOC uncertainty to total damage uncertainty, with AMOC uncertainty comprising uncertainty about future AMOC developments as well as uncertainty about the cooling pattern that would follow an AMOC weakening. I combine a newly developed pattern-scaling-type emulator of the European cooling response to AMOC weakening — calibrated for different Earth system models (ESMs) — with temperature projections from multiple ESMs and emissions scenarios, alongside several damage functions. This allows me to decompose the total uncertainty in European economic damages into different drivers and estimate the share attributable to the behaviour of the AMOC.