Governing systemic climate risk: comparative insights on cascades, extreme outcomes, and policy coherence

Climate change increasingly generates systemic risks that compound across hazards, cascade through interconnected socio-ecological and socio-economic systems, and propagate across borders via trade, infrastructure networks and shared resources. Yet most adaptation policies and planning processes remain organised around individual hazards, sectors and administrative jurisdictions.

This paper synthesises findings from an exploratory comparative assessment of how adaptation governance in Europe, Southeast Asia and the United States is beginning to engage with systemic climate risks. Using desk-based review of policy documents, a short survey of national adaptation policy experts, and semi-structured interviews, the authors examine three dimensions that repeatedly constrain adaptation practice:

(i) compounding and cascading risks, including interactions between climatic and non-climatic drivers such as inequality and socioeconomic vulnerability;

(ii) deep uncertainty, including low-probability high-impact outcomes and potential climatic and ecological tipping points; and

(iii) policy interlinkages that shape whether adaptation measures deliver co-benefits, create trade-offs, or generate maladaptation.

Across all regions, policy documents increasingly acknowledge systemic risk dynamics, but operational integration is limited by fragmented mandates, sector-specific funding streams, uneven data and analytical capacity, and monitoring and evaluation systems that rarely track cross-sectoral or distributional outcomes.

The results highlight practical entry points for strengthening systemic adaptation: stress-testing priority investments against cascading failure pathways and severe futures; aligning incentives across non-climate policies that shape vulnerability; and building enabling conditions for iterative learning and shared risk ownership across levels of governance. The analytical framing and empirical lessons presented here inform the development of a forthcoming conceptual framework for systemic climate adaptation to be published by the Stockholm Environment Institute in 2026.