Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations
Article first published online: 14 DEC 2005
Copyright 2005 by the American Geophysical Union.
Geophysical Research Letters
Volume 32, Issue 23, December 2005
How to Cite
2005), Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations, Geophys. Res. Lett., 32, L23710, doi:10.1029/2005GL024368., , and (
- Issue published online: 14 DEC 2005
- Article first published online: 14 DEC 2005
- Manuscript Accepted: 27 OCT 2005
- Manuscript Revised: 21 OCT 2005
- Manuscript Received: 11 AUG 2005
 Most climate models predict a weakening of the North Atlantic thermohaline circulation for the 21st century when forced by increasing levels of greenhouse gas concentrations. The model spread, however, is rather large, even when the forcing scenario is identical, indicating a large uncertainty in the response to forcing. In order to reduce the model uncertainties a weighting procedure is applied considering the skill of each model in simulating hydrographic properties and observation-based circulation estimates. This procedure yields a “best estimate” for the evolution of the North Atlantic THC during the 21st century by taking into account a measure of model quality. Using 28 projections from 9 different coupled global climate models of a scenario of future CO2 increase (SRESA1B) performed for the upcoming fourth assessment report of the Intergovernmental Panel on Climate Change, the analysis predicts a gradual weakening of the North Atlantic THC by 25(±25)% until 2100.