Coastal setback zones can lessen Europe's future exposure to sea level rise.

Future coastal risk will largely depend on where people build and settle, and not only on increases in extreme events or sea level rise as a result of global warming. In the past, hard engineering has been used to protect settlements in coastal lowlands. However, as this option becomes less viable and more expensive due to rapidly rising sea levels, coastal managers are increasingly turning to landuse planning interventions, such as setback zones or managed retreat. Although various studies show that one of the most effective approaches is to prevent urban expansion inside the coastal floodplain, limited research has been done to assess the potential of setback zones in minimizing future coastal exposure in Europe. This study enhances our understanding of the potential of coastal setback zones of different shapes in the EU by (1) assessing the avoided urban exposure resulting from the implementation of setback zones/retreat under different socioeconomic futures and (2) providing country-specific information on which type of setback zones is most beneficial in reducing urban exposure. For this purpose, we created spatially explicit projections of urban extent that consider different socio-economic futures and different types of setback zones to examine the effectiveness of these planning strategies in decreasing future urban exposure in Europe’s coastal lowlands. Our results show that by the year 2100, the majority of EU coastal countries can reduce the exposure of new urban land by at least 50% if coastal setback zones are established; and highlight that how we plan, build, and develop urban space in the EU coastal lowlands will be the defining factor on how exposed future urban areas are to sea-level rise.