Emergence of cascading dynamics in interacting tipping elements of ecology and climate

TL;DR

This paper investigates how interactions between ecological and climate tipping elements can lead to cascading transitions, emphasizing the importance of understanding these dynamics for predicting and managing critical environmental shifts.

Contribution

It develops a qualitative framework for analyzing the long-term behavior of interacting tipping elements and highlights potential cascade scenarios in real-world systems.

Findings

Tipping cascades can occur due to interactions between subsystems.

Interactions may cause earlier or more profound tipping than isolated systems.

Examples include Greenland ice sheet and lake eutrophication cascades.

Abstract

In ecology, climate and other fields, (sub)systems have been identified that can transition into a qualitatively different state when a critical threshold or tipping point in a driving process is crossed. An understanding of those tipping elements is of great interest given the increasing influence of humans on the biophysical Earth system. Complex interactions exist between tipping elements, e.g. physical mechanisms connect subsystems of the climate system. Based on earlier work on such coupled nonlinear systems, we systematically assessed the qualitative long-term behaviour of interacting tipping elements. We developed an understanding of the consequences of interactions on the tipping behaviour allowing for tipping cascades to emerge under certain conditions. The (narrative) application of these qualitative results to real-world examples of interacting tipping elements indicates that tipping cascades with profound consequences may occur: the interacting Greenland ice sheet and thermohaline ocean circulation might tip before the tipping points of the isolated subsystems are crossed. The eutrophication of the first lake in a lake chain might propagate through the following lakes without a crossing of their individual critical nutrient input levels. The possibility of emerging cascading tipping dynamics calls for the development of a unified theory of interacting tipping elements and the quantitative analysis of interacting real-world tipping elements.