California is experiencing one of the longest droughts since the state began recording rainfall 163 years ago, but scientists say the west coast has seen worse and also anticipate that worse is yet to come.
By studying tree rings, sediment and other natural evidence, climate scientists were able to identify a string of serious droughts in the last 1,000 years that lasted 10 to 200 consecutive years. The worst megadrought in California history began in 850 A.D. and lasted 240 years. Just fifty years later, in 1140 A.D., another megadrought began and lasted at least 180 years.
The longest droughts in California during the 20th century occurred from 1987 to 1992 and from 1928 to 1934.
Home to 38 million residents, a hundred-year drought in California today would be catastrophic.
The semi-arid state is home to two massive and distinguished economies: Silicon Valley and Hollywood. More significantly, it is also home to a wide expanse of farmlands, whose system of dams, canals, and reservoirs are hard-pressed to keep up the supply of water during a dry spell. If the drought would last another ten years, these farmlands would suffer the most.
According to California's Department of Water Resources, farmers use a yearly average of 80 percent of the water consumed by people and businesses. These are sourced from rivers, lakes, and groundwater covering 34 million acre-feet. In the event of a mega-drought, farmers' water allotments would shrink to nothing. Large reservoirs would gradually dry up after five years of very little rain. The Shasta, Oroville and San Luis reservoirs won't be of any use at that point.
Farmers would try to use groundwater to keep their plantations alive, but after these underground wells go dry, they won't have much choice but to let crops die, starting with the row crops. Digging new wells would be too costly. Entire farmlands would fail to produce a substantial amount of crops to sustain its operation, and banks would eventually refuse to lend farmers any more money.
Although the federal government would most likely allocate a large sum of money as emergency aid to farm communities, a large part of the turnout still hinges on how long the drought will last and how long the state can weather it.
Large as the farmlands of California are, it only comprises about 3 percent of the entire state economy. The urban areas of California are sprawling, and, although people will eventually learn to live with less water temporarily, they have the option of using their money to buy water from elsewhere. Farms do not have that convenience.
In his 2013 State of the State speech, California Gov. Jerry Brown tried to be realistic about the state's efforts to weather the drought.
"Among all our uncertainties, weather is one of the most basic," Brown said. "We can't control it. We can only live with it, and now we have to live with a very serious drought of uncertain duration...We do not know how much our current problem derives from the build-up of heat-trapping gasses, but we can take this drought as a stark warning of things to come."
Brown officially declared a drought emergency in the state last Friday, saying that residents ought to cut water use by 20 percent. State agencies were also directed to take well-planned and systematic steps to help agricultural communities and as well as wildlife weather the severe water shortage.