Invisible tipping points magnify the risk.
Nico Wunderling 21. *Postdoctoral Researcher in the FutureLab on Earth Resilience in the Anthropocene, the Stockholm Resilience Centre, and the High Meadows Environmental Institute at Princeton. *Jonathan F. Donges, Co-Leader of the FutureLab on Earth Resilience in the Anthropocene and Working Group Leader on Whole Earth System Analysis in Research Department on Earth System Analysis of the Potsdam Institute for Climate Impact Research. *Jürgen Kurths, Senior Advisor at Research Department 4 “Complexity Science” at Potsdam Institute for Climate Impact Research (PIK) and Professor and Senior Advisor at Humboldt University Berlin. *Ricarda Winkelmann, Professor of Climate System Analysis at PIK and University of Potsdam, Physics Institute, Germany. “Interacting tipping elements increase risk of climate domino effects under global warming.” Earth System Dynamics. 6-3-2021. https://doi.org/10.5194/esd-12-601-2021
It has been shown previously that the four integral components of the Earth's climate system mainly considered here are at risk of transgressing into undesirable states when critical thresholds are crossed (Schellnhuber et al., 2016; Lenton et al., 2008). Over the past decades, significant changes have been observed for the polar ice sheets as well as for the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest (Lenton et al., 2019). Should these climate tipping elements eventually cross their respective critical temperature thresholds, this may affect the stability of the entire climate system (Steffen et al., 2018).
In this study, we show that this risk increases significantly when considering interactions between these climate tipping elements and that these interactions tend to have an overall destabilising effect. Altogether, with the exception of the Greenland Ice Sheet, interactions effectively push the critical threshold temperatures to lower warming levels, thereby reducing the overall stability of the climate system. The domino-like interactions also foster cascading, non-linear responses. Under these circumstances, our model indicates that cascades are predominantly initiated by the polar ice sheets and mediated by the AMOC. Therefore, our results also imply that the negative feedback loop connecting the Greenland Ice Sheet and the AMOC might not be able to stabilise the climate system as a whole, a possibility that was raised in earlier work using a Boolean modelling approach (Gaucherel and Moron, 2017).
While our conceptual model evidently does not represent the full complexity of the climate system and is not intended to simulate the multitude of biogeophysical processes or to make predictions of any kind, it allows us to systematically assess the qualitative role of known interactions of some of the most critical components of the climate system. The large-scale Monte Carlo approach further enables us to systematically take into account and propagate the substantial uncertainties associated with the interaction strengths, interaction directions and the individual temperature thresholds. This comprehensive assessment indicates structurally robust results that allow qualitative conclusions, despite all of these uncertainties.