From Jonathan Overpeck last month in Nature (gated):
The complexity of these megadroughts still defies complete explanation and yet it implies that unusually persistent anomalies of sea surface temperature can combine with amplifying changes in vegetation and soil to drive droughts that — if they happened today — would outstrip many of our institutional capacities to deal with such aridity. For example, another tree-ring study highlighted a 50-year drought, with only one normal year of precipitation, in the headwaters of both the Colorado River and the Rio Grande during Roman times. It is hard to imagine how such a drought would play out today, but it would surely prove a much greater challenge to regional water resources and forests than any drought of the past 120 years.
Fifty years of drought, with only one year of normal precipitation. Holy moly. I’d like more discussion of what our “institutional capacities to deal with such aridity” might look like, rather than just a sweeping assertion. We’ve seen our “institutional capacities” able to deal with drought outside of historical experience. But holy moly. Fifty years?