Capturing cascading consequences is required to reflect risk from climate change and natural hazards

Climate change and natural hazards present a major risk to individuals and communities; however, the current quantitative risk assessment methodologies struggle to capture the wider consequences that arise from society’s complex interconnections. These complex interconnections exist due to the number of mutually dependent systems and mean that impacts on one system can be felt in another. These cascading impacts present a major challenge to climate risk assessments. Climate risk assessments often consider a range of “wellbeing” or “value” domains; for example, in New Zealand the five wellbeing domains are Natural Environment, Human, Economic, Built Environment, and Governance. Existing assessments have sought to characterize the risk to each domain, but do not quantitatively or rigorously consider the interplay between the domains. For example, how does the risk to the human domain change as a result of the impacts to the built environment? This interplay and the ensuing cascading impacts could substantially modify the assessed risk. The change could potentially alter the prioritization and subsequent adaptation plans. In this paper, we show that considering cascading impacts not only increases the magnitude of risk but can shift the prioritization. This highlights the importance of capturing cascading impacts for effective adaptation to climate change.