PESETA III, task 8 : coastal impacts : JRC PESETA III project

Coastal zones contain large human populations and significant socio-economic activities. They also support diverse ecosystems that provide important habitats and sources of food. One third of the EU population lives within 50 km of the coast. Globally about 120 million people are exposed annually to tropical cyclone hazards, which killed more than 300,000 people since 1980. Climate change could have profound impacts on coastal zones due to sea level rise and changes in frequency and/or intensity of storms. The present document reports the methodology and results of the coastal analysis under PESETA III. We employed the integrated risk assessment tool LISCoAsT (Large scale Integrated Sea-level and Coastal Assessment Tool) for Europe to evaluate coastal flood risk along the European coastline in view of climate change. The overall approach builds on the disaster risk methodology proposed by the IPCC SREX (IPCC, 2012) report, defining risk as the combination of hazard, exposure and vulnerability. We produced projections of Extreme Sea Levels (ESLs) along Europe's coastline using dynamic models forced by CMIP5 climate projections for RCP4.5 and RCP8.5. Extreme sea levels were translated into flood inundation maps using 2-D hydraulic modelling taking into account coastal flood protection. For the flooded areas direct flood damage was calculated by combining flood inundation depth with land use information and regional depth-damage functions for specific land use classes. The number of people affected was estimated by overlaying the flood inundation maps with a high-resolution population density map for Europe. Expected Annual values were used to present the findings, i.e. the expected annual impact obtained after considering all possible flood events. The study focuses on direct impacts of coastal flooding only and does not address the effects of acidification in coastal areas. Moreover, combined flooding scenarios remain an open research question for the scientific community and are not taken into account (meaning simultaneous fluvial and coastal flooding), but are the topic of ongoing exploratory studies. Processes such as dyke failure and coastal erosion are neglected, as their consideration remains a challenge given the complex processes as well as temporal and spatial scales involved. However, the above processes can drive additional risks therefore it is important to highlight that the present study may underestimate flood impacts.