ClimTip project webinar “Reconciled warning signals in observations and models suggest a nearing AMOC tipping point”

Key details

Title: Reconciled warning signals in observations and models suggest a nearing AMOC tipping point
Speaker: Yechul Shin http://climate.snu.ac.kr/portfolio/yechul-shin/?ckattempt=1 (Seoul National University)
Date: 4 March, 2025
Time: 2:00–3:00 pm CET
Webinar link: Join here (ClimTip main Zoom room)

Abstract

The Atlantic Meridional Overturning Circulation (AMOC), as recorded in paleoclimate proxies, is one of the climate systems with a potential abrupt transition. Increasing identification of statistical signals—critical slowing down—in observational fingerprints empirically raises concerns that the system may be approaching a tipping point.

However, state-of-the-art Earth System Models (ESMs) rarely project an abrupt collapse of AMOC, and its loss of stability has yet to be thoroughly investigated, leaving it unclear whether warning signals of AMOC tipping are overlooked in ESMs or exaggerated in fingerprints.

Here, a warning signal over the deep convection site of AMOC is consistently identified in both observations and ESM, and we present that the currently observed signal is reconciled with the modeled one, with warming exceeding the Paris Agreement goal. This warning signal is in accordance with physical stability of the AMOC, the AMOC-induced freshwater convergence into the Atlantic basin, is overestimated in the ESM, so that it projects a delayed tipping point.

These results suggest that the observed AMOC is approaching a tipping point akin to the projections of models simulating a much warmer Earth, underscoring potentially overlooked risks in ESMs assessments.