Remember water? We’re not quite at the point of calling it a thing of the past — but it sure looks to become scarce in the U.S. West, says a new study in the journal Science. It’s not natural weather variability or volcanic activity, say researchers, but quite clearly climate change that is leading to swiftly declining snowpack in Western mountains, which leads to rivers running dry, which leads to towns and cities short on what had been a consistent supply of power, irrigation, and thirst-quenching H2O. Climate change makes “modifications to the water infrastructure of the western U.S. a virtual necessity,” says the study. As lead author Tim Barnett puts it, “Mother Nature is going to stop being our water banker.”