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| Titel |
Sea Level Change for Norway: Past and Present Observations and Projections to 2100 |
| VerfasserIn |
Matthew Simpson, Jan Even Øie Nilsen, Oda Ravndal, Kristian Breili, Hilde Sande, Halfdan Kierulf, Holger Steffen, Eystein Jansen, Mark Carson, Olav Vestøl |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250136638
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| Publikation (Nr.) |
 EGU/EGU2016-17729.pdf |
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| Zusammenfassung |
| Changes to mean sea level and/or sea level extremes (e.g., storm surges) will lead to changes
in coastal impacts. These changes represent a changing exposure or risk to our society. Here
we try to synthesize our understanding of past and present observed sea level changes for
Norway, as well as providing sea level projections up until 2100. Our primary focus is
changes to mean sea level but we also give updated return heights for each coastal
municipality in Norway.
We first analyse observed sea level changes from the Norwegian tide gauge network and from
satellite altimetry. After the tide gauge data have been corrected for the effects of glacial
isostatic adjustment, we show that 20th century sea level rise in Norwegian waters is broadly
similar to the global average rise. Contributions to the observed sea level change and
variability are discussed. We find that rate of sea level rise along the Norwegian coast is
significantly higher for the period 1993–2014 than for the period 1960–2010. It is unclear,
however, to what extent this higher rate represents natural variability rather than a sustained
increase owing to global warming.
Our regional sea level projections are based on findings from the Fifth Assessment Report
(AR5) of the Intergovernmental Panel for Climate Change (IPCC), and the Coupled Model
Intercomparison Project phase 5 (CMIP5) output. Average projected 21st century relative sea
level change in Norway is -0.10–0.35 m (5 to 95% model ranges which is the likely range in
AR5; P>66%) for RCP2.6, -0.05–0.45 m for RCP4.5, and 0.10–0.65 m for RCP8.5. The
relative sea level projections can differ as much as 0.50 m from place to place. This pattern is
governed by the vertical uplift rates. Quantifying the probability of levels above the likely
range (i.e., the upper tail of the probability distribution) remains difficult because information
is lacking. And of particular concern is that the ice sheet contribution might have a skewed
distribution, which would mean values in its upper tail would be quite large.
Finally, we show how the estimated return heights can be combined with our regional sea
level projections to provide allowances. Allowances give the height by which an asset needs
to be raised so that the probability of flooding remains preserved for a given sea level change.
A possible attractive option in planning. |
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