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

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.

Network dynamics of drought-induced tipping cascades in the Amazon rainforest

“…6 has the normal form of a saddle-node bifurcation and is a simple form of a differential equation with two stable states. Such equations have been suggested to model dynamics in various contexts such as economics, ecology or the Earth system 63,64,65 . The two states are stable depending on the value of the critical function F crit where +1.0 stands for full tree cover and´1.0 for the alternative state without full tree cover.…”

“…This value is derived from the discriminant of the polynomial of Eq. 6 and more details can be found in literature 64,66 . In our case, the rainforest cells are not independent, but interact via moisture recycling such that Eq.…”

Smart Nutrient Retention Networks: a novel approach for nutrient conservation through water quality management

“…Good water quality itself results in higher nutrient retention by the self-reinforcing feedback loop between macrophytes and water clarity within the waterbody. Finally, on the hydrological network level, the increased nutrient retention within the waterbody decreases nutrient loading to downstream waterbodies, where the feedback chain could repeat itself (i.e., has spatial cascading effects; Klose et al 2020), resulting in a self-reinforcing feedback loop for the entire network of inland waters.…”

Anticipation-induced social tipping: can the environment be stabilised by social dynamics?

“…While there is already quite a consolidated understanding of the dynamics within single tipping elements [27,28], especially from the natural realm [29,30], it remains an important task of ongoing research to study interactions between different elements, specifically across the climate and the social system [9,31], since exemplary studies have shown that such interactions can give rise to substantial changes of such systems on the macro-scale [32,33]. Recent work has investigated also the interaction of tipping elements in natural [34][35][36][37][38], social [19], socio-economic [39], or socioecological systems [40]. However, most of the aforementioned studies have either studied tipping elements using identical prototypical normal forms for each element [35][36][37][38]40] or by focussing on cascading effects and interactions within either only natural or social subsystems [19,[34][35][36][37][38] and thus without explicitly accounting for their potential cross-system interactions.…”