Climate change can involve alterations in the pattern of freshwater transport by the atmosphere, which can affect ocean circulation with consequent feedback to the climate. Here we explore the effects of varying atmospheric moisture transport from the Atlantic to the Pacific (dfwx) and between the tropics and the extra-tropics of the North Atlantic (dfwy). To test the Grid capabilities of GENIE, 961 independent 4000 year simulations of GENIE-Trainer were made using a Condor pool of 230 workstations at London e-Science Centre. The results (below) were obtained in around 3 days and show a collapse of Atlantic circulation across a wide range of forcing. The white dot is the present (unperturbed) state, which is found to be relatively close to the ‘cliff edge’ where the Atlantic circulation collapses, eliminating the Gulf stream. Courtesy of Tim Lenton, Centre for Ecology and Hydrology, Edinburgh

Results from R.Marsh and M.Gulamali, image by A.Yool