We began our journey in 2025 as the HIPP Cohort “Making Sense of Tipping Points for Biodiversity: Ecosystem and Societal Perspectives” as a group of researchers working from diverse perspectives including ecology, mathematics and human geography. The prominent use of the term ‘tipping’ in environmental sciences and policy considerations has been at the heart of our collective discussions and we argue that it warrants deeper consideration. Here, we share some thoughts on what this term means and promises within our various fields and for public environmental debate at large.
‘Tipping points’ have a concise mathematical and physical definition linked to the modelling of how systems change over time. In this setting, tipping points characterize shifts in the stability of landscape, when a system jumps into a new state after a parameter changes. For example, a lake can remain a clear, macrophyte-dominated community, despite increasing nutrient load – until a critical moment in which the macrophytes community transforms, and is replaced by a turbid, microalgae-dominated community. Even if the nutrient load is reduced, the lake may not immediately return to its macrophyte community. An important insight from such models is that reversing changes does not always result in a return to its previous state. This is known as “hysteresis”, which signals why prevention is often easier than recovery. Models provide a way to think about such complex systems, making them useful tools for both science and policy making.
From an ecological perspective, prediction can be a powerful tool and models that allow us to anticipate changes to our ecosystems are essential. This is likely why looking at ‘tipping points’ is an attractive framework for understanding changes and informing policy. However, it is unclear whether ecological systems follow the precise rules for a system state change. Coral reefs illustrate why tipping points are hard to identify in practice. Reefs are rarely destroyed by a single event, instead they are weakened slowly by bleaching, overfishing, and pollution over years. When a sudden event occurs, like an urchin die-off, it can look like a tipping point. But the system may have already been losing resilience gradually, exhausting its capacity to buffer disturbance. This makes it difficult to pinpoint exactly when, or whether, a classical ‘tipping point’ was crossed. It also changes how we think about recovery: if a reef collapsed because of many accumulated pressures rather than one critical threshold, simply removing one stressor may not be enough to bring it back. This, in turn, raises the question of when and how to intervene based on what kind of mechanism is pushing the system to cross this critical point. Recognising this complexity is essential for realistic conservation planning. The complex nature of the structure and dynamics of ecological systems shields us from seemingly abrupt changes, but we are losing this buffering capacity in light of the current biodiversity crisis. Understanding what is driving degradation in target systems and how much recovery is feasible may ultimately be more useful than debating whether a tipping point was actually crossed.
Does a focus on global tipping points obscure the view of local contexts?
These environmental discussions on tipping points further extend our attention towards reflections in geography around the key concepts of scale and discourse. Scientists and policy-makers increasingly discuss ‘global tipping points’ in relation to the global agenda of climate change. They identify Earth system components in which tipping could lead to catastrophic changes (melting of specific ice sheets, overturning of oceanic circulation), as well as ‘positive tipping points’ where small but self-amplifying social changes may lead to a more ‘sustainable world.’ The ‘global’ backdrop of both perspectives is, however, not neutral, and has come to be a dominant worldview and outlook of climate change – making climate governance a global issue in itself. But, a key question we should ask is what this means for local contexts. What might be sidelined, or ignored by prioritizing ‘global challenges’? As a discourse, our interest extends to how we imagine and convince the world around us, based on how it is narrated and characterized (in the media, online, through conversation). Discourses of the global produce imaginaries of ‘scaled-up’ modes of environmental governance. They shape how we feel (and therefore, act) about the world. Do conversations of tipping points make us feel anxious, indifferent, bored? Such concerns become key governance challenges: what do we prioritize, and how?
Ecosystems are complex, and fuzzy systems with boundaries that are hard to define. Policymakers are often interested in quick and convenient solutions, whereas socio-ecological systems move at different scales and pace. The ‘tipping points’ discourse is ultimately shifting efforts from meaningful climate action. How can the scientific community address these issues and communicate them clearly in order for urgent actions to be taken? Our multidisciplinary engagement with ‘tipping points’ has allowed us to identify the various ways of thinking with this term and pinpoint some key (but productive) tensions, as well as reflect on how scientific terminology and thinking are received (or not) by policy or wider public narrative. By having this dialogue beyond a single viewpoint, we have stepped outside our scientific comfort zone, and encourage you to do the same.
Stay tuned for further updates from the Tipping Point cohort.