Abstract
The heat transported northwards by the North Atlantic thermohaline circulation warms the climate of western Europe1,2,3. Previous model studies4,5,6 have suggested that the circulation is sensitive to increases in atmospheric greenhouse-gas concentrations, but such models have been criticised for the use of unphysical ‘flux adjustments’7,8,9 (artificial corrections that keep the model from drifting to unrealistic states), and for their inability to simulate deep-water formation both north and south of the Greenland–Iceland–Scotland ridge, as seen in observations10,11. Here we present simulations of today's thermohaline circulation using a coupled ocean–atmosphere general circulation model without flux adjustments. These simulations compare well with the observed thermohaline circulation, including the formation of deep water on each side of the Greenland–Iceland–Scotland ridge. The model responds to forcing with increasing atmospheric greenhouse-gas concentrations by a collapse of the circulation and convection in the Labrador Sea, while the deep-water formation north of the ridge remains stable. These changes are similar intwo simulations with different rates of increase of CO2 concentrations. The effects of increasing atmospheric greenhouse-gas concentrations that we simulate are potentially observable, suggesting that it is possible to set up an oceanic monitoring system for the detection of anthropogenic influence on ocean circulation.
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References
Manabe, S. & Stouffer, R. J. Two stable equilibra of a coupled ocean-atmosphere model. J. Clim. 1, 841–866 (1988).
Hall, M. M. & Bryden, H. L. Direct estimates of ocean heat transport. Deep Sea Res. 29, 339–359 (1982).
Roemmich, D. & Wunsch, C. Two transatlantic sections: meridional circulation and heat flux in the subtropical North Atlantic Ocean. Deep Sea Res. 32, 619–664 (1985).
Manabe, S. & Stouffer, R. J. Century-scale effects of increased atmospheric CO2on the ocean–atmosphere system. Nature 364, 215–218 (1993).
Murphy, J. M. & Mitchell, J. F. B. Transient response of the Hadley Centre coupled model to increasing carbon dioxide. Part II. Temporal and spatial evolution of patterns. J. Clim. 8, 57–80 (1995).
Cubasch, U. et al. Time-dependent greenhouse warming computations with a coupled ocean-atmosphere model. Clim. Dyn. 8, 55–69 (1993).
Rahmstorf, S. Risk of sea-change in the Atlantic. Nature 388, 825–826 (1997).
Houghton, J. T. et al. (eds) Climate Change 1995: the Science of Climate Change(Cambridge Univ. Press, (1996).
Marotzke, J. & Stone, P. H. Atmospheric transports, the thermohaline circulation, and flux adjustments in a simple coupled model. J. Phys. Oceanogr. 25, 1350–1364 (1995).
Rahmstorf, S. Bifurcations of the Atlantic thermohaline circulation in response to changes in the hydrological cycle. Nature 378, 145–149 (1995).
Dickson, R. R. & Brown, J. The production of North Atlantic Deep Water: sources, rates and pathways. J. Geophys. Res. 99, 12319–12341 (1994).
Johns, T. C. et al. The second Hadley Centre coupled ocean-atmosphere GCM: model description, spinup and validation. Clim. Dyn. 13, 103–134 (1997).
Roether, W., Roussenov, V. M. & Well, R. in Ocean Processes in Climate Dynamics: Global and Mediterranean Examples(eds Malanotte-Rizzoli, P. & Robinson, A. R.) 371–394 (Kluwer, Dordrecht, (1994).
Gent, P. & McWilliams, J. C. Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. 20, 150–155 (1990).
Roberts, M. J. & Wood, R. A. Topgraphic sensitivity studies with a Bryan-Cox type ocean model. J.Phys. Oceanogr. 27, 823–836 (1997).
Gordon, C. et al. The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments. Clim. Dyn.(in the press).
Levitus, S. & Boyer, T. P. World Ocean Atlas 1994(NOAA/NESDIS E/OC21, US Dept of Commerce, Washington DC, (1994).
Houghton, J. T. et al. (eds) Climate Change 1992: the Supplementary Report to the IPCC Scientific Assessment(eds Houghton, J. T., Meira Filho, L. G., Callander, B. A., Harris, N., Kattenberg, A. & Maskell, K.) (Cambridge Univ. Press, (1996).
Weaver, A. J. & Hughes, T. M. C. On the incompatibility of ocean and atmosphere models and the need for flux adjustments. Clim. Dyn. 12, 141–170 (1996).
Bryan, F. O. Climate drift in a multi-century integration of the NCAR Climate System Model. J. Clim. 11, 1455–1471 (1998).
Bacon, S. Decadal variability in the outflow from the Nordic seas to the deep Atlantic Ocean. Nature 394, 871–871 (1998).
Clarke, R. A. Transport through the Cape Farewell–Flemish Cap section. Rapp. P.-v. Réun. Cons. Int. Explor. Mer. 185, 120–130 (1984).
Rahmstorf, S. & Ganopolski, A. Long-term global warming scenarios computed with an efficient coupled climate model. Clim. Change(in the press).
IPCC Workshop Report on Rapid Non-linear Climate Change(Intergovernmental Panel on Climate Change, Bracknell, (1998).
Dickson, R., Lazier, J., Meincke, J., Rhines, P. & Swift, J. Long-term coordinated changes in the convective activity of the North Atlantic. Prog. Oceanogr. 38, 241–295 (1996).
Stocker, T. F. & Schmittner, A. Influence of CO2emission rates on the stability of the thermohaline circulation. Nature 388, 862–865 (1997).
Wadley, M. R. & Bigg, G. R. Abyssal channel flow in ocean general circulation models with application to the Vema Channel. J. Phys. Oceanogr. 26, 38–48 (1996).
Doescher, R. & Redler, R. The relative importance of northern overflow and subpolar deep convection for the North Atlantic thermohaline circulation. J. Phys. Oceanogr. 27, 1894–1902 (1997).
Parilla, G., Lavin, A., Bryden, H. L., Garcia, M. & Millard, R. Rising temperatures in the subtropical North Atlantic Ocean over the past 35 years. Nature 369, 48–51 (1994).
Lazier, J. R. N. in Natural Climate Variability on Decade-to-century Timescales(eds Martinson, D. G. etal.) 295–302 (Nat. Academy Press, Washington DC, (1995).
Acknowledgements
We thank H. Cattle, G. Jenkins, J. Murphy, S. Rahmstorf, R. Stouffer, R. Thorpe and A. Weaver for comments. This work was supported by the UK Department of the Environment, Transport and the Regions.
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Wood, R., Keen, A., Mitchell, J. et al. Changing spatial structure of the thermohaline circulation in response to atmospheric CO2 forcing in a climate model. Nature 399, 572–575 (1999). https://doi.org/10.1038/21170
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DOI: https://doi.org/10.1038/21170
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