Simulations of Climate Change for IPCC AR4
Sea Level
The sea surface height is affected by many different processes, acting on different time scales: short term changes due to wind or tides as well as long-term global changes due to variations of the climate and earth system. The fundamental factors for long-term changes are:
- Volume changes of ocean water as a consequence of changing temperatures (steric expansion)
- Changes of the global ocean circulation (dynamic adjustment)
- Growing or melting of the large ice sheets (Greenland, Antarctic) or mountain glaciers (eustatic change)
- Changes of the ocean basins volume due to uplift and subsidence of the earth's crust (tectonic change)
The following simulations consider steric and dynamic changes, but do not account for eustatic or tectonic effects.
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Changes of the mean global sea level are strongly influenced by the level of greenhouse gas concentrations in the atmosphere. The simulations show that - depending on the IPCC-SRES emission scenario - a global mean sea level change of 21 to 28 cm (compared to the period 1961-1990) can be expected. |
Since the ocean is able to store large amounts of heat, the sea level will still continue to rise even when the concentrations of the different greenhouse gases in the atmosphere are not increasing any more. For the scenarios A1B and B1 the simulations have been continued with constant concentrations (values of 2100) for the period between 2100 and 2200.
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Regional differences in the sea level changes are caused by changes of the ocean circulation and the hydrologic cycle (precipitation minus evaporation). In the high southern latitudes changes of the sea level during the 21st century are comparatively small; in the Arctic Ocean, however, sea level rises more than twice as much relative to the global mean, due to an increasing fresh water influx from rivers and precipitation. Shifting ocean circulation patterns can also result in deviations of regional sea level changes from the global mean - e.g. in the North Atlantic.
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Comparison of th sea level changes of the scenarios A2 and B1 for the period between 2000 and 2100. Changes occur particularly in the end of the century. (Mpeg1, 2.4 MB bzw. JPEG 100 kB) |
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Sea level changes of the scenario A2 for the period between 2000 and 2100. (Mpeg1, 2.5 MB bzw. JPEG 100 kB) |
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Sea level changes of the scenario A1B for the period between 2000 and 2100. (Mpeg1, 2.5 MB bzw. JPEG 100 kB) |
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Sea level changes of the scenario B1 for the period between 2000 and 2100. (Mpeg1, 2.5 MB bzw. JPEG 100 kB) |
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Sea level changes of the scenario A1B for the period between 2000 and 2200. (Mpeg1, 5 MB bzw. JPEG 100 kB) |
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Sea level changes of the scenario B1 for the period between 2000 and 2200. (Mpeg1, 5 MB bzw. JPEG 100 kB) |
Mor information about sea level rise can be found in the FAQs on the homepage of the Max-Planck-Institute for Meteorology.
Felix Landerer from the Max Planck Institute for Meteorology investigates the connection between regional sea level changes and climate relevant ocean processes in reponse to a global climate change.
Visualisation: Michael Böttinger, DKRZ