A new parameterization of eddies in a coarse resolution ocean model yields deep ocean salinities and temperatures that are significantly closer to observations than with previous parameterizations. This is achieved because dense water is able to flow over sills and into the deep ocean without being diluted with the surrounding water. In addition, the depth to which surface-induced tracers penetrate in the Southern Ocean is now realistic. This depth is overestimated by previous ocean models, including those used to estimate global warming. Adding this new eddy parameterization to coupled atmosphere-ocean models is expected to yield greater global warming. ¿ American Geophysical Union 1996