Uncertainty and bias in global to regional scale assessments of current and future coastal flood risk
This paper provides the first comparative assessment of uncertainties in global to world-regional scale studies of current and future coastal flood risks based on the published literature. One of the main impacts of climate change is sea-level rise leading to more frequent flooding of low lying coastal areas through higher tides, storm surges and waves. In this context, assessments of current and future coastal flood risk at global to world-regional scales are needed to inform policy decisions on greenhouse gas reduction targets and finance of adaptation and flood disaster risk reduction. A key requirement for such assessments is that they consider all major uncertainties in models, methods and data applied, because the failure to do so may lead to poor policy outcomes.
The authors find that globally, by far the largest uncertainty concerns how coastal societies will adapt to sea-level rise, which can influence future flood risk by factors 20–27. Other large global uncertainties are associated with socio-economic development, digital elevation data, greenhouse gas emissions, and ice sheet evolution, influencing global exposure and flood risk by factors of up to 2 to 6.