The Rio Grande: climate science and policy’s forgotten river, Episode XVII

Columbia University’s Richard Seager has a helpful new paper out about the impact of climate change on water supplies in the western United States. At the core is an approach Seager has used before, looking not only at precipitation in a changing climate, but also at evaporation. (See here for a story I did in 2007 about his work.)

The new paper uses the latest and greatest CMIP5 (Coupled Model Intercomparison Project Five) climate models, allowing some useful downsizing to clarify the effects of the west’s complex geography. Seager and his colleagues then estimated runoff in Texas, in the Colorado River Basin and in the California-Nevada region. But not the Rio Grande. The Colorado River gets all the science-policy love, and now Texas, with its drought as big as, well, Texas. Once again, we get the scraps.

Not to worry, though. As Seager explained to me, the Rio Grande Basin, sandwiched between Texas and the Colorado River Basin, appears at risk of the same fate of rising temperatures and declining water supply:

Given the location of the Rio Grande basin, to the west of Texas and extending up towards the headwaters of the Colorado River, and given the patterns of change in P, and P-E, I would expect similar conclusions for changes in Rio Grande runoff as we found for Colorado River and Texas runoff.

Here’s Seager’s map, with seasonal precipitation in the left-hand column and P-E in the right. I’ll have more in the newspaper this weekend: