USGS Contributions to the Climate Change Science Program

The Global Change Hydrology Program was begun in 1990 to develop data, understanding, and predictive capabilities related to water and associated aspects of carbon and greenhouse gases as they interact with global systems. Global Change Hydrology has two broad components: 1) investigations of hydroclimatic variability, and 2) studies of the biogeochemistry of greenhouse gases. This includes identification of seasonal variations in regional streamflow in relation to atmospheric circulation (for regional streamflow prediction and flood/drought hazard assessment); the linkage between atmospheric circulation and snowpack accumulation (for forecasting spring and summer water supply in the western United States and for flood forecasting) as well as glacier mass balance; and the physical and chemical variability in riverine and estuarine environments in relation to large-scale atmospheric and oceanic conditions (to discriminate natural from human-induced effects on such systems). It also includes documenting the long-term behavior of hydrologic systems in response to past climatic variations and changes (from decades to hundreds of thousands of years) as well as more recent (decadal) hydrologic trends.

Late winter snow and ice on the Sheepscot River in coastal Maine. USGS scientists are studying 20th century trends in river flows, river ice, and lake ice in New England to analyze hydrologic effects of observed climate variability. Significantly earlier spring snowmelt runoff, river-ice breakups, and lake-ice breakups have occurred in the last 30 years.