“The 21st century for sure is being characterized by persistent, ubiquitous drought in the West,” Deke Arndt, chief of the climate monitoring branch of the National Climatic Data Center, recently told The New York Times. “The projection is for that to continue.”
Californians, now suffering through their fourth year of severe, record-breaking drought, are now facing mandatory water restrictions from the state government. On Wednesday, Governor Jerry Brown ordered a statewide 25 percent reduction in water use.
Though a Stanford University study recently found that the conditions for the current drought are exacerbated by increased carbon concentrations in the atmosphere, climate change is not the sole factor. California has historically experienced a natural drought cycle. However, scientists have stated that global warming is intensifying and prolonging drought conditions.
“It used to be that half the years were warm, and half were cool,” Noah Diffenbaugh, an associate professor in earth sciences at Stanford, told NYT. “Now we’re in a regime where most of the years are warm.”
The heat causes what little snow California receives to turn to rain, and that rain to quickly evaporate. Presently, the snowpack in the Sierra Nevada Mountains, a chief source of water in the spring and summer, is at six percent its average level.
To illustrate the magnitude of the problem, NASA has released two images of the Sierra Nevadas taken by its Aqua satellite. The first is from March 27, 2010, the last year of average snowfall in the region.
The second image shows the same region on March 29, 2015. Not only has the snow cover markedly diminished, the Central Valley (one of the nation’s most fertile agricultural centers) has also dried up. NASA notes that most of the white in the 2015 image is actually cloud cover.
“It looks from our snow courses and pillows that statewide, we have about half or less of the lowest April 1 snowpack on record,” said Frank Gehrke, chief of the California Cooperative Snow Surveys.
Scientists working with NASA’s Airborne Snow Observatory have stated that the snowpack at the Tuolumne River Basin in the Sierra Nevadas is 40 percent of what it was at its highest level in 2014, “which was already one of the two driest years in California’s history,” NASA writes.
As higher temperatures hit California, there is less water to be found in its reservoirs, rivers and soil. Now that winter is over, it is unlikely that the state will receive much more. NASA senior water scientist Jay Famiglietti has warned that California has about one year’s supply of stored water left.