Discussions about climate change and water supply in the western United States risk getting bogged down in pursuit of uncertainties. Those uncertainties are real, but there’s a bunch that we already know, and it’s sufficient to help us form policy responses, according to a new summary paper from the Colorado River Research Group:

Assuming the current drought will end, and that the supply/demand problems in the basin will thus fade away, is both nai?ve and dangerous. A return to “normal” (i.e., 20th century) precipitation patterns would be unlikely to result in a return to normal levels of runoff, as steady warming will continue to erode streamflows. The “new normal” is variability and change, likely in directions that further stress the basin’s water resources. A risk management philosophy that assumes continued climate variability and change is the correct way forward, rather than an approach that views current conditions as something calling for a temporary coping strategy until normal conditions resume.

The question now is really more about policy than it is about science:

To ensure further progress, the research and water management communities need to improve efforts in coordination and mutual understanding, bringing political leaders into the loop to speed the implementation of solutions that are beyond the capability of scientists and managers alone.