Coastal cities are hotspots of risks related to natural hazards. Already today, many of these cities face high economic and non-economic losses from disasters and creeping environmental changes. However, risks in coastal cities are expected to rise even further, fuelled by the interplay of two global mega-trends: climate change and continued coastal urbanization. The question of how to adapt cities to the hazards of the future is therefore of great concern – not only for scientists, but also for policy makers and risk practitioners. The relevance of this question even increases when considering the central role of coastal cities in economies and societies at the global scale, for instance, in terms of trade, transport, and culture.

However, a number of important scientific knowledge gaps persist with regards to risk assessment and adaptation analysis in coastal cities. While the assessment of future risk trends in these cities is predominantly focused on scenarios of future hazards (sea level rise, floods, typhoons, etc.), scenarios of socio-economic changes and hence future trends in exposure and vulnerability are typically not part of the picture due to a lack either of awareness or adequate methods and data. This lack is significant and leads to potentially flawed and imprecise assessments of future risk trends and eventually adaptation needs. Secondly, knowledge on the feasibility of different – often competing – adaptation options remains thin. It is too often based on a reductionist set of evaluation criteria, e.g. economic costs and benefits, and a view towards singular adaptation measures, e.g. hard coastal protection. Integrative and comparative assessments that evaluate different adaptation options (e.g. retreat vs. flood accommodation) against a wider set of criteria such as social acceptance or political feasibility are still poorly developed. Thirdly, scientific engagement with coastal urban risk too often remains within siloes of different disciplines (engineering, sociology, economics, planning, etc.). This hampers interdisciplinary assessments and leads to significant blind spots, e.g. with respect to private sector adaptation or collective action for adaptation across different groups of actors.

The special issue aims at making a significant contribution towards closing these knowledge gaps. It is open to theoretical, methodological, and empirical contributions and will combine a mixture of research articles, review articles, and brief communications. Submissions for all these manuscript types are therefore welcome. Both local case studies from across the globe as well as regional- or and global-level perspectives are invited. The special issue is particularly interested in contributions that draw on combined perspectives from different disciplines. A particular focus will be on coastal cities with high growth dynamics and adaptation pressure, as can be observed in many transition economies of Asia and Africa.