Setting the stage for decision-making on nature-based solutions for coastal climate adaptation

Nature-based solutions (NbS) are fast becoming the norm for multifunctional coastal climate adaptation to increased sea-level rise. However, informing decision-makers about NbS presents ongoing challenges. This study set out to identify and explore the information requirements at different stages of the decision-making process of coastal NbS. Developing and applying a novel methodological approach, we analysed the values and indicators discussed in four key decision-making stages: the advocacy, political, bureaucratic and provisioning stages. Applied to a mega beach nourishment in the Netherlands, our study identified substantial differences in information requirements across the decision-making stages. Most notably, the values and indicators discussed shifted from being abstract to becoming increasingly specific and concrete as the stages progressed. Our findings emphasize the importance of recognizing the distinct stages of decision-making and tailoring the content and level of abstraction of information accordingly. Additionally, they suggest that future changes in the content and concretisation of the information required for decision-making on coastal NbS can be anticipated and prepared for. By distinguishing and understanding the decision-making stages in NbS, this study bridges a longstanding gap between decision-making and NbS studies, thereby allowing for improving the fairness, implementation, evaluation and comprehension of trade-offs of coastal NbS. This study progresses the understanding of the information required for planning, implementing, evaluating and managing coastal NbS, advancing multifunctional coastal climate adaptation for shores worldwide.