Projections of global‑scale extreme sea levels and resulting episodic coastal flooding over the 21st Century

Global models of tide, storm surge, and wave setup are used to obtain projections of episodic coastal fooding over the coming century. The models are extensively validated against tide gauge data and the impact of uncertainties and assumptions on projections estimated in detail. Global “hotspots” where there is projected to be a signifcant change in episodic fooding by the end of the century are identifed and found to be mostly concentrated in north western Europe and Asia. Results show that for the case of, no coastal protection or adaptation, and a mean RCP 8.5 scenario, there will be an increase of 48% of the world’s land area, 52% of the global population and 46% of global assets at risk of fooding by 2100. A total of 68% of the global coastal area fooded will be caused by tide and storm events with 32% due to projected regional sea level rise.