New Video: California Drought – Natural, Man Made, or Both?
March 13, 2014
I was asked weeks ago to do an update on the California drought situation – which seemed pretty straightforward at the time – but it turned into one of the most challenging assignments I’ve taken on.
Not only has the weather situation continued to morph, but the political dialogue heated up as well, when the President travelled to the state and mentioned climate as a contributor to the drought conditions. Hysteria ensued.
Aside from the predictable political fallout from this very critical, very visible, and potentially crippling weather event, there is a very real ongoing debate in the science community as to when an event can be attributed to climate change, and how much.
I spent a lot of time interviewing a range of scientists, both in and outside California, on the history of drought cycles in the state, as well as the effects of the slow but persistent signal of climate warming on that variable cycle. Dr. Kathleen Johnson of UC Irvine shared with me her research on the central California paleo-climate, derived from cave geology.
One confounding factor is the exponential population growth that has occurred during an era when the state has been, historically speaking, relatively lush with water – a condition that the paleo-record warns, is temporary under the best scenario, as I was reminded by Dr. Bill Patzert and Dr. Tom Painter, both of NASA JPL.
But, even given that, it is impossible to ignore the emerging exploration in the science literature for possible changes in atmospheric dynamics that may be part of a warming climate. We’ve become used to the cycles we know, such as El Nino/LaNina, Pacific Decadal Oscillation, North Atlantic Oscillation – but as Dr. Richard Rood of the University of Michigan, and Dr. Aradhna Tripati of UCLA told me, there is no guarantee that these are set in stone.
Finally I talked to Dr. Jacob Sewall, whose computer modeling of a decade ago forecast that declines in arctic sea ice might mean future circulation pattern eerily similar to the stubborn, “ridiculously resilient ridge” that has produced the spectacularly variable weather from the arctic, to North America, to Europe, this winter.