SEA THE CHANGE

Dynamic Adaptive Policy Pathways (DAPP) is a decision-making tool designed to support flexible and dynamic long-term climate adaptation under deep uncertainty. It is developed by Dutch water-management researchers and based on lessons from the 1953 North Sea flood that shaped the Dutch Delta Programme. This paper examines how DAPP provides solutions for coastal adaptation within the Dutch Delta Programme. This study draws on peer-reviewed literature and policy documents, applying an analytical framework to identify gaps between the theoretical foundations and the practical implementation of DAPP. Results show that the Dutch Delta Programme operationalises DAPP through Adaptive Delta Management (ADM), using four Delta Scenarios to explore plausible climate and socio-economic futures. Based on this analysis, the programme defines Delta Decisions - strategic coastal adaptation measures - to align short-term actions with long-term climate uncertainties. ADM is supported by continuous monitoring from the National Signal Group, which provides annual assessments and feeds into a six-year evaluation cycle. Delta Decisions are implemented within a multi-level governance system coordinated by the Delta Commissioner. The programme continues to strengthen the Netherlands’ primary flood defences through large-scale sand nourishment, dune reinforcement, and the upgrading of dikes and storm-surge barriers to maintain a climate-resilient coastline. Despite the advanced institutionalisation, the implementation of ADM remains demanding due to multi-level governance challenges, uncertainties in sea-level rise projections, and limited financial resources, provided by the Delta Fund. The Dutch Delta Programme serves as a pioneering best-practice example for long-term flood- risk management. Implementing DAPP enables flexible long-term responses under deep uncertainty, while institutional challenges provide lessons for other countries.

Managed realignment (MR) is increasingly used as a nature-based adaptation strategy to respond to increasing coastal flood risk. By relocating existing defense lines further inland while breaching former dikes, MR seeks to reduce incoming wave energy and erosion, while providing space for the development of intertidal habitats, particularly saltmarshes. This review paper examines the adaptive capacity of MR to sea level rise (SLR) by reviewing existing literature and identifying the key features that determine MR adaptability. Under appropriate conditions, MR can serve as an effective buffer against SLR, although its performance remains highly dependent on the actual rate of SLR. Studies have shown that natural saltmarshes can potentially keep pace with mod- erate SLR, such as under the RCP 4.5 scenario, but are unlikely to fully buffer more extreme scenarios like RCP 8.5. Since artificially created marshes in MR sites gener- ally perform below the level of natural marshes, their capacity to provide protection is expected to be correspondingly lower. We found that the resilience of MR sites to sea- level rise depends largely on whether created saltmarshes can accrete fast enough to keep pace with rising water levels. Several key factors, such as sufficient sediment supply, tidal range, site topography, and appropriate site design, have been identified to enhance their effectiveness under rising sea levels. Monitoring the implemented sites and future research will be crucial for evaluating long-term effectiveness and guid- ing adaptive strategies to improve MR performance.

Oceans and other marine ecosystems cover approximately 71% of the Earth´s surface. They play a key role in todays society, economics, transport and culture. While these values and resulting need for protection of marine ecosystems have already been established at the Rio Earth Summit in 1992, the practical implementation of this conservation goal remains a global challenge. This is largely due to different usage patterns of the various users of marine areas which often influence each other and have been considered mutually exclusive in spatial planning. Non-economic interests have not been included in past decision-making processes due to their lack of partici- pation opportunities. One approach to amend these shortcomings can be found in the „blue economy“ concept under the name of „marine spatial planning“ (MSP), which aims to organize the sustainable use of marine spaces in a planned and participatory process in order to ensure a legally binding long-term equity between all actors and stakeholders in marine areas. In Germany, a plan for the usage of the exclusive eco- nomic zone (EEZ) has been established in 2009. The first implementations have been changed in 2021 and recently in 2025 also adding the concept of multi-use. While some parts of the marine spatial plan in Germany clearly require improvements, multi-use offers great potential for a more equitable use of marine areas and resources for future generations.