Sources of 21st century regional sea-level rise along the coast of northwest Europe
Changes in both global and regional mean sea level, and changes in the magnitude of extreme flood heights, are the result of a combination of several distinct contributions most, but not all, of which are associated with climate change. These contributions include effects in the solid earth, gravity...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-06-01
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| Series: | Ocean Science |
| Online Access: | http://www.ocean-sci.net/10/473/2014/os-10-473-2014.pdf |
| Summary: | Changes in both global and regional mean sea level, and changes in the
magnitude of extreme flood heights, are the result of a combination of
several distinct contributions most, but not all, of which are associated
with climate change. These contributions include effects in the solid earth,
gravity field, changes in ocean mass due to ice loss from ice sheets and
glaciers, thermal expansion, alterations in ocean circulation driven by
climate change and changing freshwater fluxes, and the intensity of storm
surges. Due to the diverse range of models required to simulate these
systems, the contributions to sea-level change have usually been discussed
in isolation rather than in one self-consistent assessment. Focusing on the
coastline of northwest Europe, we consider all the processes mentioned
above and their relative impact on 21st century regional mean sea
levels and the 50-year return flood height. As far as possible our
projections of change are derived from process-based models forced by the
A1B emissions scenario to provide a self-consistent comparison of the
contributions. We address uncertainty by considering both a mid-range and an
illustrative high-end combination of the different components.
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For our mid-range ice loss scenario we find that thermal expansion of
seawater is the dominant contributor to change in northwest European sea
level by 2100. However, the projected contribution to extreme sea level, due
to changes in storminess alone, is in some places significant and comparable
to the global mean contribution of thermal expansion. For example, under the
A1B emissions scenario, by 2100, change in storminess contributes around
15 cm to the increase in projected height of the 50-year storm surge on the
west coast of the Jutland Peninsula, compared with a contribution of around
22 cm due to thermal expansion and a total of 58 cm from all of the
contributions we consider. An illustrative combination of our high-end
projections suggests increases in the 50-year return level of 86 cm at
Sheerness, 95 cm at Roscoff, 106 cm at Esbjerg, and 67cm at Bergen. The
notable regional differences between these locations arise primarily from
differences in the rates of vertical land movement and changes in
storminess. |
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| ISSN: | 1812-0784 1812-0792 |