How to assess coastal flood risk in data-sparse coastal lowlands? Accurate information on land elevation is key

With rising sea level, the densely populated coastal lowlands in the world, many of them located in the Global South, face increasing flood risks and thus require reliable flood risk assessments. As these rely on land elevation information in relation to local sea level, both the accuracy and vertical reference of the data used strongly affect the reliability of such assessments. We therefore 1) provide an overview of the appropriate use of elevation data and considerations to be made, and 2) call for global public availability of high-accuracy elevation data.