HR: 08:00h
AN: GC11A-01    [Abstracts]
TI: Long-term Future Sea Level Changes Simulated with a Complex Earth System Model
AU: * Vizcaino, M
EM: vizcaino-trueba@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146 Germany
AU: Mikolajewicz, U
EM: mikolajewicz@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146 Germany
AU: Groeger, M
EM: groeger@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146 Germany
AU: Maier-Reimer, E
EM: maier-reimer@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146 Germany
AU: Schurgers, G
EM: schurgers@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg, 20146 Germany
AU: Winguth, A
EM: ramwinguth@wisc.edu
AF: Center for Climatic Research Department of Atmospheric and Oceanic Sciences, 1225 W Dayton St, Madison, WI 53706 United States
AB: The melting of glaciers and the ocean thermal expansion associated with a future warmer climate are expected to produce significant sea level changes in the next centuries. Besides this environmental impact, the melting from continental size glaciers (the ice sheets of Greenland and Antarctica) could perturb the large-scale climate by changing the ocean circulation, albedo and atmospheric circulation patterns. Here we offer an assessment of sea level changes and the impacts of ice sheets in future climate by means of a modelling approach, where all main components of the physical and biogeochemical system are included (atmosphere, ocean physics, sea ice, land vegetation, ocean biogeochemistry and ice sheets) with detailed representation of the main processes in each of these components. The core of the coupled Earth System Model is the ECHAM3/LSG AOGCM. Ice sheets are simulated with a three-dimensional ice sheet model coupled bidirectionally to the other components. The experiments performed show the evolution of the climate from the pre-industrial climate until year 4000 under historical emission scenarios for the period 1750-2000, prescribed IPCC emission scenarios (A2, A1B and B1) for the 21st century and extrapolated IPCC scenarios for the period from 2100. The melting of the Greenland ice sheet is relatively moderate for all scenarios, due to the moderate sensitivity of the coupled model to changes in the CO₂ concentrations. The collapse of the thermohaline circulation (THC) in the most extreme scenario (A2) prevents an otherwise stronger reduction of the ice sheet volume. The five member ensemble simulation for the more realistic scenario A1B provides an interesting frame for the evaluation of the impact of the stability of the THC in the evolution of the ice sheets, since the THC collapses in three realizations, and does not collapse in the other two. The increased of Antarctic ice sheet volume due to increased snowfall rates compensates the melting from Greenland for all scenarios. The net sea level rise resulting from the sum of the contributions is positive due to the effect of ocean thermal expansion, which ranges from 0.25 to 2 m of sea level, depending on the scenario.
UR: http://www.mpimet.mpg.de/en/depts/dep3/oph/deklim.html
DE: 1621 Cryospheric change (0776)
DE: 1622 Earth system modeling (1225)
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 4962 Thermohaline
SC: Global Climate Change [GC]
MN: Fall Meeting 2005