Accounting for systemic complexity in the assessment of climate risk

Widespread changes to climate-sensitive systems are placing increased demands on risk assessments as a key for managing climate risk, enabling adaptive responses and enhancing system resilience. Although the complex, uncertain and ambiguous nature of climate-sensitive systems has been long recognised, recent attention on concepts such as compounding and cascading risks, deep uncertainty and ‘bottom-up’ risk assessment frameworks have stressed the need to more explicitly confront the overarching theme of systemic complexity. Drawing on insights from the field of systems thinking, we provide a theoretical foundation for addressing systemic complexity when assessing climate risks. We first describe the sources of systemic complexity as they pertain to climate risk, and highlight the role of climate risk assessment as a formal sense-making device that enables learning and the organisation of knowledge of the interplay between the climate-sensitive system and its (climatological) environment. We then highlight boundary judgements as one of the core concerns of risk assessment, acting as a filter of both information and value judgements, and thereby creating islands of analytical and cognitive tractability in a complex, uncertain and ambiguous world. Yet boundary judgements necessarily result in partiality, leading to the need for boundary critique, which emphasises the need of multi-methodologies and second-order learning processes as part of standard risk assessment practice. We build these concepts into a framework that divides climate risk assessments into five distinct but interrelated concerns or ‘problematics’ that collectively can be used as a starting point for managing systemic complexity in the assessment of climate risk.