CEE Seminar: Global Change and the Water Cycle

Warming induced by anthropogenic emissions of greenhouse gases can induce changes in precipitation and other components of the water cycle. At the same time, human perturbations such as irrigation and water management can also directly perturb the hydrological fluxes. Understanding the regional and global changes of precipitation and hydrologic extremes is important for improving societal resilience to environmental changes. The seasonal cycle of precipitation is dominantly influenced by the seasonal cycle of solar insolation, but even precipitation seasonality can be altered by global warming in many ways, with implications for floods, droughts, wildfires, and food production. Water use and management may also alter the seasonality of streamflow and hydrologic extremes. In this talk, I will present examples of how warming may sharpen and amplify the seasonal cycle of precipitation in California and the Pacific Northwest, respectively, and delay the onset of monsoon rainfall. I will also present some recent advances in earth system modeling, allowing the impacts of irrigation and water management on the seasonality of streamflow and stream temperature to be investigated, with implications for hydrological drought and thermoelectric power production.