Processes at the ice shelf-ocean interface and in particular in ice shelf cavities around Antarctica have an observable effect on the solutions of basin scale to global coupled ice-ocean models. Despite this, these processes are not routinely represented in global ocean and climate models. It is shown that a new ice shelf cavity model for z coordinate models can reproduce results from an intercomparison project of earlier approaches with vertical σ or isopycnic coordinates. As a proof of concept, ice, shelves are incorporated in a 100-year global integration of a z coordinate model. In this simulation, glacial meltwater can be traced as far as north as 15°S. The observed effects of processes in the ice shelf cavities agree with previous results from a σ coordinate model, notably the increase in sea ice thickness. However, melt rates are overestimated probably because the parameterization of basal melting does not suit the low resolution of this configuration. Copyright 2008 by the American Geophysical Union.