PNNL

Abstract

What makes a climate risk more “severe” or “dangerous” than others, and what are the conditions driving severity over time? This Perspective paper builds on recent literature to explore this question through three notions that are estimated foundational to risk severity: the physical and socio-ecological thresholds leading to transformational and possibly abrupt changes; the irreversibility of these changes; and the cascading effects both within and across the systems affected. It also takes stock on the sensitive issues of the spatial scale(s) of and the evidence base on severe climate risks. Noting that severe climate risks remain largely under-studied, it proposes three intertwined research directions across geographies, sectors and populations, that are expected to play a critical role in the coming decade, from feeding the next IPCC cycle to, more broadly, support the development of anticipatory adaptation policies.