Identifying key behavioural determinants and intervention spaces in policymakers’ climate adaptation decision-making

As climate change progresses, the urgency to adapt has increased, yet current climate adaptation efforts remain insufficient. While psychological research has explored behaviour change interventions for citizens, policymakers are often overlooked. Policymakers are central to advancing adaptation efforts as they decide which policy instruments to prioritise to increase societies’ resilience to climate risks. Despite this, the existing basis for designing context-tailored behavioural interventions to improve their decision-making remains underdeveloped. In this study, we integrate a systematic scoping review of 70 studies and an expert Delphi panel to identify key behavioural determinants of policymakers’ adaptation decision-making and to prioritise target behaviours and behaviour change techniques (BCTs). We analysed the behavioural determinants and BCTs present in research on adaptation policymaking using the Theoretical Domains Framework and Behaviour Change Technique Taxonomy. Policymakers’ context, resources, and knowledge, as well as social influences, are the most frequently reported behavioural determinants. The most commonly applied techniques to improve decisions involve setting goals, making plans, and building knowledge. The Delphi panel of behavioural science experts and Dutch climate adaptation policy professionals was conducted in two rounds ( n 1 = 47, n 2 = 32) and identified seven key behaviours, which primarily occur in intermediate decision-making phases. It also prioritised BCTs, showing that making plans, setting goals, increasing knowledge, and providing social support were rated as the most implementable and acceptable intervention techniques. Contrasting our results with the peer-reviewed literature reiterates the value of integrating behavioural, policy, and systems approaches for effective, context-tailored behavioural intervention designs. Based on the results, we were able to identify promising intervention spaces for effective, implementable behavioural interventions targeting climate adaptation policymakers within the Dutch context. We provide recommendations for future research to develop and test such interventions as well as to generalise our findings in other contexts.