While adapting to future sea-level rise (SLR) and its hazards and impacts is a multidisciplinary challenge, the interaction of scientists across different research fields, and with practitioners, is limited. To stimulate collaboration and develop a common research agenda, a workshop held in June 2024 gathered 22 scientists and policymakers working in the Netherlands. Participants discussed the interacting uncertainties across three different research fields: sea-level projections, hazards and impacts, and adaptation. Here, we present our view on the most important uncertainties within each field and the feasibility of managing and reducing those uncertainties. We find that enhanced collaboration is urgently needed to prioritize uncertainty reductions, manage expectations and increase the relevance of science to adaptation planning. Furthermore, we argue that in the coming decades, significant uncertainties will remain or newly arise in each research field and that rapidly accelerating SLR will remain a possibility. Therefore, we recommend investigating the extent to which early warning systems can help policymakers as a tool to make timely decisions under remaining uncertainties, in both the Netherlands and other coastal areas. Crucially, this will require viewing SLR, its hazards and impacts, and adaptation as a whole.

Deltas worldwide are at risk of elevation loss and drowning due to relative sea-level rise. Management strategies to restore or enhance sedimentation on delta plains, Sedimentation-Enhancing Strategies (hereafter SES), are now being pursued in many deltas but there has been limited cross-disciplinary and cross-delta review. Here we compare 21 existing and planned SES, synthesizing their physical characteristics, funding, governance arrangements, stakeholder engagement, process of implementation, environmental impact, land use change, and potential for upscaling. Strategies exist at various scales, from ~0.05 km² - 500 km². 79% of strategies are capable of outpacing high rates of sea-level rise. Cheaper strategies are limited to short term impacts and small spatial scales, while more expensive strategies can have longer lifetimes. Most strategies create wetlands and flood water storage. Some create opportunities for agriculture, aquaculture, housing, or recreational land use. Combinations of SES will likely be the most effective and sustainable method for maintaining elevation in river deltas.