But that reality hasn’t stopped heated arguments from springing up in recent days over the cause or causes of California’s continuing epic drought. Is one of the drivers the growing human influence on the climate? Or is this drought something we’ve seen before, the result of natural variability?
In the wake of an unusual public debate on this issue between President Obama’s science adviser, John Holdren, and Roger Pielke, Jr., a longtime analyst of climate-related disaster losses at the University of Colorado, I received a helpful note from Martin Hoerling, who studies climate extremes for the National Oceanic and Atmospheric Administration.
Hoerling’s conclusions echo those of another longtime student of western drought, Richard Seager of Columbia University, as reported in Justin Gillis’s recent news report on the issue. “I’m pretty sure the severity of this thing is due to natural variability,” Seager told Gillis.