As the world grapples with the monumental task of reducing greenhouse gas emissions, restoring nature and adapting to increasing climate impacts, a new category of risk is coming into focus: the risk that the very transition to sustainability could be derailed. This “derailment risk” arises when climate and ecological shocks undermine our ability to act, rather than simply being consequences of inaction.

Traditionally, climate risk assessments have emphasized two main types: “physical risks” — such as extreme heatwaves, floods, and ecosystem collapse; and “transition risks” — which include stranded assets, job disruptions and shifts in policy or technology. Yet a growing body of research suggests there is a third category: risks to the transition itself. Put simply, the ability of societies to carry out mitigation, restoration and adaptation may be weakened by the escalating impacts of climate and nature loss.

Researchers from institutions including the Global Systems Institute, University of Exeter, University College London and other global universities have developed models that explore how biophysical changes — like ecosystem breakdown or major climate tipping-points — combine with socio-economic pressures to create feedback loops that sap our capacity to act. In this framing, if the world becomes preoccupied with damage control, responding to cascading disasters, then less effort and resources remain for the forward-looking work of transitioning to sustainability.

Consider an example: if multiple bread-and-butter sectors — agriculture, energy, transport — are disrupted by climate extremes, the political will, public attention and financial resources may shift away from long-term climate strategies and toward emergency response. That diverts focus from the systemic change needed, increasing the likelihood that mitigation stalls, nature continues to degrade and a spiral of worsening impacts begins. This is derailment risk in action.

The research points out that tackling derailment risk requires shifting how we think about climate strategy. Rather than only quantifying losses or emissions, we must strengthen the underlying capacity of societies to act: resilient infrastructure, governance systems that can handle shocks, adaptive institutions, and social systems that maintain momentum even under duress. By doing so, we preserve the “work” — human labour, financial investment, political energy — necessary to maintain the transition even as the planet changes.

The authors emphasise that positive dynamics are also possible: crisis can spark rapid transformations if managed well. For example, a major shock could prompt accelerated policy innovation, mass mobilisation of low-carbon technology or rapid ecosystem restoration. The key is to anticipate the structural risks to the transition, embed them in planning and build systems that are robust to disruption rather than brittle.

In essence, the message is two-fold: yes, we must act — fast. But we must also act in such a way that we defend and strengthen our ability to act. Without this dual focus, the sustainability transition may not fail because of technical inability alone, but because our societies become overwhelmed by the very changes they seek to avert.