The recent Intergovernmental Panel on Climate Change (IPCC) assessment of greenhouse warming scenarios suggests an intensification (increase in cycling rates) of the global hydrological cycle over the next several decades. Accurate incorporation of water and energy cycles can substantially improve the predictive capability of global climate models. The Global Energy and Water Experiment (GEWEX) Science Conference offered an opportunity to determine how well the various components of the hydrological cycle can be quantified. The GEWEX project, which seeks to understand how water and energy interact with the global climate, is making progress in seasonal-to-interannual forecasting and decade-to-century scale climate prediction— two of the four major themes of the U.S. Global Change Research Program. We review here some of the highlights of the conference.