Abrupt climate change as a rate-dependent cascading tipping point

Johannes Lohmann,Daniele Castellana,Peter D Ditlevsen,Henk A Dijkstra

doi:10.5194/esd-12-819-2021

Johannes Lohmann, Daniele Castellana + Show 2 more

Open Access

https://doi.org/10.5194/esd-12-819-2021

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Abstract

Abstract. We propose a conceptual model comprising a cascade of tipping points as a mechanism for past abrupt climate changes. In the model, changes in a control parameter, which could for instance be related to changes in the atmospheric circulation, induce sequential tipping of sea ice cover and the ocean's meridional overturning circulation. The ocean component, represented by the well-known Stommel box model, is shown to display so-called rate-induced tipping. Here, an abrupt resurgence of the overturning circulation is induced before a bifurcation point is reached due to the fast rate of change of the sea ice. Because of the multi-scale nature of the climate system, this type of tipping cascade may also be a risk concerning future global warming. The relatively short timescales involved make it challenging to detect these tipping points from observations. However, with our conceptual model we find that there can be a significant delay in the tipping because the system is attracted by the stable manifold of a saddle during the rate-induced transition before escaping towards the undesired state. This opens up the possibility for an early warning of the impending abrupt transition via detection of the changing linear stability in the vicinity of the saddle. To do so, we propose estimating the Jacobian from the noisy time series. This is shown to be a useful generic precursor to detect rate-induced tipping.

Highlights

Multiple elements in the Earth system are believed to be at risk of undergoing abrupt and irreversible changes in response to rising atmospheric greenhouse gas concentrations
In this work we propose a conceptual model that describes a mechanism for abrupt climate change comprising a rateinduced resurgence of the Atlantic Meridional Overturning Circulation (AMOC) as a response to increasing atmosphere–ocean heat exchange, which results from fast disappearance of sea ice
Building on previous studies of proxy records and state-ofthe-art climate models, we propose that past abrupt climate change could have arisen as a cascade of tipping points

Summary

Introduction

Multiple elements in the Earth system are believed to be at risk of undergoing abrupt and irreversible changes in response to rising atmospheric greenhouse gas concentrations. It constitutes a risk that deserves attention as it has been observed across the hierarchy of climate models (Weijer et al, 2019), and there is evidence that it has occurred repeatedly during the last glacial period (Henry et al, 2016). Such past changes in the AMOC likely led to abrupt climate changes known as Dansgaard–Oeschger (DO) events (Dansgaard et al, 1993). These are the most significant instances of large-scale climate change in the past, but the underlying mechanisms remain debated

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