The existential space of climate change and systemic risks

Climate change is widely recognized as a major risk to societies and natural ecosystems but the cascading processes of impacts through complex and interconnected systems are poorly understood. In fact, the high end of the risk, i.e. where risks become existential, is poorly framed, defined and analyzed by science. This gap is at odds with the fundamental relevance of existential and systemic risks for humanity, and it also limits the ability of scientific communities to engage with the emerging debates and narratives about the existential dimension of climate change that have recently gained considerable traction.

In this contribution we address this gap by scoping and defining existential risks related to climate change. We first review the context of existential risks and climate change, as related to systemic risks and drawing on research in fields such as global catastrophic risks and the so-called “Reasons for Concern” in the reports of the Intergovernmental Panel on Climate Change. We also consider how existential risks are framed in the civil society climate movement and what we can learn in this respect from the COVID-19 crisis, which is also a primary learning space for better understanding for both, systemic and existential risks. We then develop a definition that distinguishes between a narrower scope of conditions that threaten survival and basic needs, and a broader scope of conditions that threaten a certain level of well-being, consisting of meeting acceptable living standards. Based on this, we define six dimensions of existential risks of climate change, including the mechanisms they unfold, the systems affected, the dimension and magnitude, the probability of occurrence, time horizon and speed, and the scale of the threat. Our contribution is intended to support further scientific analysis of existential and systemic risks as part of the full risk space associated with climate change. Considering the widespread lag in awareness and regulation related to systemic risks, the results of this study should make the risk space better defined, more tangible and hence more conducive to preventive action by policy.