Sea level rise projections for Northern Europe under RCP8.5

posted Jun 17, 2015, 3:58 AM by Aslak Grinsted   [ updated Jul 1, 2016, 1:14 AM ]
Regional sea level projection for Northern Europe for six different uncertainty percentiles (5,17,50,83,95,99%). The 50% median projection can be considered the best guess.
Sea level rise poses a significant threat to coastal communities, infrastructure, and ecosystems. Sea level rise is not uniform globally but is affected by a range of regional factors. In this paper, we calculate regional projections of 21st century sea level rise in Northern Europe, focusing on the British Isles, the Baltic, and the North Sea. The input to the regional sea level projection is a probabilistic projection of the major components global sea level budget. Local sea level rise is partly compensated by vertical land movement from glacial isostatic adjustment. We explore the uncertainties beyond the likely range provided by IPCC, including the risk and potential rate of marine ice sheet collapse. Our median 21st century relative sea level rise projection is 0.8 m near London and Hamburg, and a relative sea level drop of 0.1 m in the Bay of Bothnia (near Oulu, Finland). Considerable uncertainties remain in both the sea level budget, and in the regional expression of sea level rise. The greatest uncertainties are associated with Antarctic ice loss and uncertainties are skewed towards higher values, with the 95th percentile being characterized by an additional 0.9 m sea level rise above median projections. 


Grinsted, Jevrejeva, Riva, Dahl-Jensen (2015), Sea level rise projections for Northern Europe under RCP8.5, Clim. Res., doi:10.3354/cr01309

Some conclusions
We find that there is a considerable risk that existing high-end scenarios for sea level rise may be exceeded. 

"The median projection is considerably higher than the mid-range/central projections offered in the UKCP 2009 report (Lowe et al., 2009), in Katsman et al. (2008). The ‘High++’ scenario (0.9-1.9m) in UKCP09 was regarded as very unlikely (Lowe et al., 2009), but here we estimate a 27% chance of local sea level in London exceeding 93 cm under RCP8.5 (and a 3% chance of exceeding 1.9 m). Similarly, we find that there is a 26% chance of exceeding the high-end local sea level rise scenario constructed for the Netherlands in Katsman et al. (2011) under RCP8.5."

Data: Projections for individual cities

Data files with the RSL projection uncertainties for individual cities is attached below. In practice, the uncertainties are given as a cumulative density function of the RSL projection in each city. Some additional info such as the applied GIA rate, and derived quantities such as mean and standard deviation is given in the header to each file.

[Download dataUpdate 7Jul16: an earlier version of the file listed expected LSL instead of expected RSL in the header. This has been corrected.

Special issue on Effects of Extreme Global Warming in Northern Europe

The paper is part of a special issue on Effects of Extreme Global Warming in Northern Europe. In this issue there are some cases which highlight how difficult it will be to adapt to a 6 degree C warmer world, and when that would happen under different scenarios. For sea level rise i instead chose to focus on RCP8.5. The special issue has many contributions from our Centre for Regional change in the Earth System.

Trivia: all colormaps were generated using hslcolormap
Uncertainties in projected RSL - Grinsted2015
Aslak Grinsted,
Jul 1, 2016, 1:11 AM