Human-induced changes in the hydrology of the western United States


Barnett, T., Pierce, D.W., Hidalgo, H., Bonfils, C., Santer, B.D., Das, T., Bala, G., Wood, A.W., Nazawa, T., Mirin, A,, Cayan, D., Dettinger, M. . 2008. Human-induced changes in the hydrology of the western United States. Science Science Express Reports 10.1126/science.1152538.


Observations have shown the hydrological cycle of the western U.S. changed significantly over the last half of the twentieth century. Here we present a regional, multivariable climate-change detection and attribution study, using a high-resolution hydrologic model forced by global climate models, focusing on the changes that have already affected this primarily arid region with a large and growing population. The results show up to 60% of the climate related trends of river flow, winter air temperature, and snow pack between 1950-1999 are human-induced. These results are robust to perturbation of study variates and methods. They portend, in conjunction with previous work, a coming crisis in water supply for the western United States.