A look at the historic 2011-2016 California drought and the work of Stanford Earth faculty and researchers to better understand its causes, implications, and mitigation.
In 2011, the US Drought Monitor showed that California was nearly free of drought. By the start of 2012, the California drought began. The state hasn’t experienced a drought of this severity in over a century. (source: US Drought Monitor)
December 2013: Stanford Earth PhD student Daniel Swain identified an atmospheric phenomenon he nicknamed the “Ridiculously Resilient Ridge,” a region of persistent high pressure. The Ridge effectively acts as a large stone in the atmospheric river, forcing cooler, wetter air away from western North America. Swain linked this unique climate pattern to the onset of the California drought. Red areas show region of high pressure, while blue regions show regions of lower pressure (image courtesy of Daniel Swain)
January 2014: Governor Jerry Brown declares a drought state of emergency for California. (photo by Justin Short, Office of the Governor)
February 2014: The California government creates a workshop to study the use of satellites to monitor groundwater aquifers, a scientific method called “remote sensing.” As water is removed from the aquifer, the ground above drops – movement that satellites can measure from orbit. (image courtesy of Canadian Space Agency/NASA/JPL-Caltech)
May 2014: Stanford Earth researchers Jessica Reeves (above), Rosemary Knight, Howard Zebker, and their collaborators published one of the first studies that demonstrated that satellite remote sensing technology can visualize the movements associated with fresh groundwater withdrawal and recharge. The colors indicate how far Earth’s surface moved, and the red box identifies a circular pattern indicative of groundwater removal. (images courtesy of Jessica Reeves)
August 2014: Comedian Conan O’Brien teams with the Natural Resources Defense Council (NRDC) and the drought awareness program Save Our Water to create humorous PSAs urging Californians to save water (image courtesy of TeamCOCO.com)
September 2014: Stanford Earth researchers Daniel Swain (right), Noah Diffenbaugh (left), Bala Rajaratnam, and their collaborators published studies linking an increased risk of California drought to climate change. This was the first time climate scientists were able to demonstrate this connection (photo by Stacy Geiken)
August 2015: California water use dropped by 31.3%, more than the previously mandated 25% (photo by Miles Traer).
September 2015: Scientists from the National Oceanic and Atmospheric Association (NOAA) identify strong El Nino conditions in the Pacific Ocean. Researchers predict that these semi-regular ocean-climate conditions will bring much-needed rain to California. Darker reds indicate regions with higher than normal temperatures, indicative of El Nino conditions (image courtesy of NOAA).
September 2015: Stanford Earth professors Noah Diffenbaugh and Chris Field wrote in the New York Times that the predicted wet El Nino conditions will likely not alleviate all of the impacts of the California drought.
January 2016: A series of strong storms hit California, bringing Northern California to near or above its average seasonal precipitation to date. Climate researchers caution that the state has accumulated a multi-year water deficit equivalent to 2.5-3 years’ worth of precipitation, a quantity unlikely to fall during a single winter season. (photo by Brocken Inaglory via Wikimedia Commons)
“Understanding the link between climate change and the Ridiculously Resilient Ridge will be crucial in characterizing the future risk of severe drought in California” –Noah Diffenbaugh (above) (image courtesy of Kurt Hickman)