California is prone to droughts, and the historic record points to numerous long and severe dry spells. It is difficult to show scientifically that climate change is responsible for this or that particular drought, but scientists agree that a warmer climate intensifies droughts when they do occur.
The current drought is exceptional. A recent tree ring study shows no comparable dry spell in the past 1,200 years.
Climate change will not necessarily bring entirely new kinds of events: droughts, rainstorms, and tropical storms are not first-ever events. Rather, with the warming climate, such familiar events gradually become more intense and damaging. Current weather events now bear the burdens of a changed global atmosphere.
The California drought is part of a persistent atmospheric pattern that is also behind the extreme winter events in eastern North America in recent years – known to scientists as the “Ridiculously Resilient Ridge” over Alaska and Canada, and as the “Terribly Tenacious Trough” dipping into the eastern U.S.
This pattern may be enhancing ocean heating in the northeastern Pacific, a novel pattern scientists have dubbed “the Blob.” And it has consequences beyond just impacts on western industry and agriculture, extending to fisheries and the food chain itself.
This month’s Yale Climate Connections “This Is Not Cool” video recognizes that making the connection from this drought to climate change is not “settled science.” But most scientists agree that it is the type of event that will occur more often in a warming world.