The new paper by Ben Cook and colleagues clarifying our understanding the risk of megadrought in the southwestern United States has rightly gotten a lot of attention. Combining paleo records and modeling of a changing climate under rising greenhouse gas scenarios, Cook and his colleagues have created some scary reading:
[F]uture drought risk will likely exceed even the driest centuries of the Medieval Climate Anomaly (1100–1300 CE) in both moderate (RCP 4.5) and high (RCP 8.5) future emissions scenarios, leading to unprecedented drought conditions during the last millennium.
My question to you, dear readers: What are the policy implications? In what way is this actionable? If you’re Terry Fulp at the Bureau of Reclamation’s Lower Colorado River Regional Headquarters in Boulder City, Nev., or Jeff Kightlinger at the Metropolitan Water District of Southern California, or Kevin Kelly at the Imperial Irrigation District, what would you be doing different today, now that you have had a chance to read Cook et al., that you weren’t already doing a month ago, before the paper came out?