Danish Climate Atlas view on sea level change in future

Wind patterns projected for the region, together with sea level rise and land rise, call into question our current understanding of extreme storm surges in the Danish coastal area. The Danish Meteorological Institute (DMI) will research changes in the extreme statistics of sea level in the twenty-first century through the 'Danish Climate Atlas,' a new national climate service initiative. The study will make use of multi-scenarios, multi-models and multi-parameters approach to focus on the uncertainty of the projected change in extreme statistics of sea level.  Historical sea level records suggest that the relative sea level (RSL) along the Danish North Sea coast south of Skagerrak has been increasing with the global mean sea level (GMSL) rise. However, RSL has been absent in the central Skagerrak-Kattegat Seas, owing to the Fennoscandian post-glacial land-uplift offsetting the GMSL rise. According to the recent IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), due to Antarctic ice sheet dynamics, GMSL would grow more than previously estimated in the IPCC Fifth Assessment Report (AR5) by the end of the twenty-first century under RCP8.5. We regionalized the SROCC sea level forecasts for the "Danish Climate Atlas" dataset. Our findings indicate that sea level projections under RCP8.5 result in a > 40 cm RSL rise in the Skagerrak-Kattegat Seas by the end of the twenty-first century, which may necessitate a new adaptation strategy in this region. Under the RCP8.5 scenario, the rate of mean sea level rise will exceed the rate of land rise earlier than previously estimated by AR5. We emphasize, in particular, the impact of these new predictions on future severe sea levels in this region. Our findings suggest that this more current GMSL prediction should be factored into coastal risk assessments in the Skagerrak-Kattegat Seas in this century.