Projecting twenty-first century regional sea-level changes

Abstract

We present regional sea-level projections and associated uncertainty estimates for the end of the 21 st century. We show regional projections of sea-level change resulting from changing ocean circulation, increased heat uptake and atmospheric pressure in CMIP5 climate models. These are combined with model- and observation-based regional contributions of land ice, groundwater depletion and glacial isostatic adjustment, including gravitational effects due to mass redistribution. A moderate and a warmer climate change scenario are considered, yielding a global mean sea-level rise of 0.54 ±0.19 m and 0.71 ±0.28 m respectively (mean ±1σ). Regionally however, changes reach up to 30 % higher in coastal regions along the North Atlantic Ocean and along the Antarctic Circumpolar Current, and up to 20 % higher in the subtropical and equatorial regions, confirming patterns found in previous studies. Only 50 % of the global mean value is projected for the subpolar North Atlantic Ocean, the Arctic Ocean and off the western Antarctic coast. Uncertainty estimates for each component demonstrate that the land ice contribution dominates the total uncertainty

Recent Progress in Understanding and Projecting Regional and Global Mean Sea Level Change

“…On the other hand, the AR5 and Slangen et al [135] projected RSL rise exceeding the global mean (by more than 20 %) on the east coast of North America and in a roughly zonal band on the north side of the Antarctic Circumpolar Current. These phenomena are due to ocean climate change.…”

“…Subsequent advances (following Katsman et al [125], Slangen et al [126], and Church et al [127]) enabled this to be done in the AR5, which therefore presented projections of RSL change including all the above-mentioned effects except tectonics, which were also excluded. A number of regional projections and projections at coastal tide gauge sites, building on the AR4 and AR5 assessments and using the AR5 approach, have also been completed [120,[128][129][130][131][132][133][134][135]. Slangen et al [135] also made RSL projections including all effects based on CMIP5 simulations of ocean climate change, combined with somewhat different estimates for the land-ice contributions from the AR5 assessment.…”

“…A number of regional projections and projections at coastal tide gauge sites, building on the AR4 and AR5 assessments and using the AR5 approach, have also been completed [120,[128][129][130][131][132][133][134][135]. Slangen et al [135] also made RSL projections including all effects based on CMIP5 simulations of ocean climate change, combined with somewhat different estimates for the land-ice contributions from the AR5 assessment. They pointed out that the distribution of RSL change is positively skewed (also seen in AR5, Fig.…”

“…As in the AR5, Slangen et al [135] projected RSL change of less than the global mean (by up to 50 %) near West Antarctica and Greenland, due to GeLi effects of the ice sheets. On the other hand, the AR5 and Slangen et al [135] projected RSL rise exceeding the global mean (by more than 20 %) on the east coast of North America and in a roughly zonal band on the north side of the Antarctic Circumpolar Current.…”

Sensitivity analysis of climate change impacts on dune erosion: case study for the Dutch Holland coast

“…While changes in sea level and wave angle will be regional (Idier et al 2013;Cazenave and Cozannet 2014;Slangen et al 2014), coastal response will be local, depending on offshore bathymetric characteristics (e.g., Claudino-Sales et al 2008), or the dune morphology themselves (e.g., Van Thiel De Vries et al 2010;De Winter et al 2015). Several impact assessments have been executed to evaluate the possible impact of climate change on local coastal hazards, such as the coast of Oregon, USA, where besides SLR, future occurrences of EL Niño are included (Baron et al 2015) or the coasts of California, USA, where different types of coasts are present (e.g.…”