Explaining the adaptation gap in Dutch coastal risk management through lock-in mechanisms

This article investigates Dutch coastal risk management in light of recent scientific evidence on long-term sea level rise. While the so-called <i>Delta Programme</i>, meant as a national boost for flood safety, remains central to the Netherlands' coastal defence strategy, our analysis reveals that it does not offer sufficient protection beyond the year 2050. It is therefore evidence of a climate adaptation gap. Drawing on the concept of lock-ins, this study examines how certain mechanisms may be at play. The study uses a framework on "adaptation lock-ins" developed by Groen et al. (2022) in an attempt to study and explain this adaptation gap. A qualitative analysis of policy documents, secondary literature and semi-structured interviews with experts points to the existence of several lock-in mechanisms which are implied in the stagnation of Dutch coastal risk management. The insights gathered are relevant for practitioners and academics alike as it might be used to inform the upcoming revision of the <i>Delta Programme</i> in 2027. At the conceptual level, the study adds insights on previously undiscovered types of lock-ins, thus adding to the explanatory power of the lock-in concept. The article concludes that further research can focus on how lock-ins vary across time, regions or contexts, and how they can be addressed and overcome.