Developing water change spectra and distinguishing change drivers worldwide

Abstract

Abstract The separate and combined effects of different drivers of change to water fluxes and resources on land (CWOL) remain difficult to distinguish and largely unknown, particularly at a global scale. Our study analyzes CWOL during the period 1901–2008, based on available hydroclimatic data for up to 859 hydrological basins. We develop a worldwide spectrum of change magnitudes and directions in Budyko space, from which we distinguish climate and landscape drivers of CWOL. We find that landscape drivers (e.g., changes in land and water use, water storage or water phase) are needed to explain CWOL in at least 74% of the basins studied. The water change effects of such landscape drivers are mostly opposite to those of atmospheric climate change. The change spectrum approach we developed provides a useful tool for quantifying and visualizing CWOL and for distinguishing the effects of climate and landscape drivers across regions and scales.