Climate effects on seawater levels

Climate effects may, in the long term, lead to a general rise in sea levels. Our assessments of future sea water levels are based on the best assumptions that can be made today, but still contain a measure of uncertainty since we do not know what the green house emissions will be in the future.

The evaluation of simulations and analyses within the area of climate change is being conducted by, among others, the Intergovernmental Panel on Climate Change (IPCC), an organisation established by the World Meteorological Organisation (WMO) and the UN.

The latest evaluation from IPCC came in spring 2007 and is based on a large number of improved climate models and improved information regarding uncertainties in the forcing.

Larger rise than expected

After the last assessment report from IPCC was produced, new information regarding future sea levels has been added. In 2008 the Dutch Delta Committee evaluated the upper limit for the sea level rise off the coast of Holland. Compared to IPCC’s evaluation the results of the Delta Committee show a higher elevation of the sea level. One reason it that the Delta Committee has captured the effect of melting land ice.

SMHI analyses Swedish waters

Detailed national analyses of Swedish waters are performed by the climate scientists at SMHI Rossby Centre. SMHI uses a model for the Baltic Sea called RCO. The scientists have developed four scenarios that describe how the seawater levels will change on a regional scale within 100 years.

We offer physical planners assessments of what the local seawater level will be in the future along a particular stretch of coast – and along with the various risk levels involved.

Part from the international and regional climate scenarios we take into account the absolute elevation of the land, which varies along the Swedish coast. The above factors are the major contributions to our calculations of future changes in average and high water levels in Swedish waters.