Here we present new isotope records derived from snow samples from the McMurdo Dry Valleys, Antarctica and re-analysis data of the European Centre for Medium-Range Weather Forecasts (ERA-40) to explain the connection between the warming of the Pacific sector of the Southern Ocean <Jacka and Budd, 1998; Jacobs et al., 2002> and the current cooling of the terrestrial Ross Sea region <Doran et al., 2002a>. Our analysis confirms previous findings that the warming is linked to the El Ni¿o Southern Oscillation (ENSO) <Kwok and Comiso, 2002a, 2002b; Carleton, 2003; Ribera and Mann, 2003; Turner, 2004>, and provides new evidence that the terrestrial cooling is caused by a simultaneous ENSO driven change in atmospheric circulation, sourced in the Amundsen Sea and West Antarctica.