Mega-Drought Threatens the American West
“The heart of the West is a desert, unqualified and absolute,” wrote prescient 20th century Texas historian Walter Prescott Webb. Nearly six decades later, the desert is returning to claim its own.
Here in Southern California, it’s the warmest winter in history and the fourth consecutive winter that never was. While much of the United States slipped and struggled in snow and ice, our winter has been dry and balmy with July-like temperatures. This week the thermometer in some inland sites touched triple digits.
California below the Tehachapi Mountains, which divides the northern and southern sections of the Golden State, gets 90 percent of its precipitation from December to March. It hasn’t been much. Los Angeles, for example, has received seven inches of rain. In the Santa Barbara area, where I live, the total is nine inches.
Many places have received less. The Sierra Nevada snowpack on which much of California depends for water is at 12 percent of normal, a record low for March. Several water storage facilities in Southern California have dropped to a third of capacity. Pine Flat Reservoir, in the rolling foothills of the San Joaquin Valley east of Fresno, is only 16 percent full.
But all that may be the good news. If the scientists who have examined tree rings that reveal weather data back to the year 1000 are right, the Southwest probably is not in the late stages of a normal drought but the beginning phase of a 35-year mega-drought -- the sort that contributed to the extinction of the ancient Pueblo peoples, or Anasazi, of the Colorado Plateau.
Scientists from NASA, Columbia and Cornell put forth these findings last month in the new journal Science Advances. They used 17 computer models of droughts and three models of soil moisture to predict the likeliness of drought over the next century.
Benjamin Cook, the study’s lead author and a scientist at NASA’s Goddard Institute for Space Studies in New York, said that if greenhouse gas emissions are reduced to “middle-of-the-road” levels it would lower the probability of a mega-drought in the Great Plains to between 60 and 70 percent. But the scientists said these reductions would have no impact on the projected mega-drought in the Southwest, where the probability of such a catastrophe would remain at 80 percent.
What’s scarier still is that this mega-drought could be could be the worst ever.
“Even when selecting for the worst mega-drought … period, the 21st century projections make [past] mega-droughts seem like quaint walks through the Garden of Eden,” said Jason Smerdon of Columbia University’s Lamont-Doherty Earth Observatory, a co-author of the study.
Two-thirds of California is now experiencing “exceptional” or “extreme” drought, the two driest categories. The official U.S. Drought Map shows these conditions extending into western Nevada and eastern Oregon. Much of every other Western state except Montana and Wyoming is undergoing “severe” or “moderate” drought.
California, with nearly 39 million people, has the largest population of any state. But after improving water conservation practices in droughts during the 1970s and 1990s, the Golden State has been slow to recognize the magnitude of the current crisis. Unlike all other states in the West, California didn’t inventory groundwater until last year.
After much talk and little action by various factions in the water wars, Gov. Jerry Brown rose to the occasion in 2014 and managed to hammer out a bipartisan consensus with legislators on behalf of a record $1.7 billion water bond. Voters approved the measure, known as Proposition 1, by a 2-1 margin.
But the consensus was short-lived. In the four months since the bond issue passed, interest groups representing farmers and environmentalists have fought a name-calling battle while nothing was done about water conservation. The State Water Resources Board met and warned of possibly dire future restrictions but took no action except for directing municipal agencies to limit the number of days in which lawn watering is allowed, which most cities are already doing.
Privately, many officials seemed to share the hope that the latest drought would end as the last one did, with a spurt of storms late in the 1991 rainy season known as the “March miracle” rains. I was Western bureau chief for The Washington Post at the time. People in Santa Barbara were so grateful for the rain that some of them walked smilingly out into the storm bareheaded.
This year, however, as winter turned into spring with soaring temperatures, Gov. Brown and legislative leaders gave up on March miracles and unveiled a plan to spend $1 billion of the Proposition 1 money to improve water infrastructure, protect wildlife and provide emergency assistance to hard-hit communities.
“This is a struggle,” Brown said at a Sacramento news conference. “Something we’re going to have to live with. For how long, we’re not sure.”
The new plan doesn’t completely satisfy Republicans, who point out that the bond issue is also supposed to provide money for new low-elevation reservoirs to collect winter rain runoff. That’s a particular need now since the air was so warm in much of the state this winter that the precipitation added little to the snowpack in the high Sierra.
As the state plans, drought-stricken cities along the California coast are turning to the seemingly limitless supplies of water in the Pacific Ocean to fill their needs.
Construction of the Carlsbad desalination plant in San Diego County is 85 percent complete. When finished later this year it will be the largest desalination plant in the Western Hemisphere, generating 50 million gallons of potable water a day.
Santa Barbara is about to take the wraps off a desalination plant that was built during the 1990s drought but mothballed after the March miracle rains. Further up the coast, the 6,000-resident town of Cambria, near the historic William Randolph Hearst Castle, has opened an expensive, energy-intensive desalination plant that uses a mix of fresh water, estuary water and highly treated sewage.
All told there are 11 desalination plants in California and another 16 on the drawing board. Most are small but even the massive Carlsbad plant will serve only 7 percent of San Diego County’s population, making it clear that more than desalination is needed to address any mega-drought.
Reclaiming wastewater, most of which runs out to sea, is high on the wish list of most water district managers. This is where the state investment in infrastructure announced last week by Brown could make a difference.
Others have more imaginative--and expensive--solutions. In the early 1990s, Alaska Gov. Wally Hickel proposed building a 1,400-mile pipeline from one of Alaska’s monster rivers to a California reservoir. Similar ideas are now popping up at water forums in California, with a somewhat shorter pipeline from Canada a popular variant. Canadians historically have been unenthusiastic about such proposals.
Meanwhile in the Central Valley, which produces much of the nation’s fresh fruit and vegetables, farmers anticipate that a million acres will lie fallow this year, twice as much as last year. That’s in large part because the federal Central Valley Project for a second consecutive year is not providing any water to farmers.
There’s a paradox in the valley. Even as the desert advances, some agricultural crops are thriving. Last year was a record year for the state’s processing tomato crop, and the U.S. Department of Agriculture forecasts another record this year. Almonds, California’s largest cash crop and one of its thirstiest, are also doing well. Almonds are the state’s biggest export crop, worth about $5 billion in 2014.
But if the scientists are right in their prediction of a mega-drought, California’s farmers are living in a dreamland.
Agricultural interests large and small are making up for lack of rain and shortage of federal and state water by drilling ever deeper into California’s largest reservoir, the underground Central Valley aquifer that extends for 400 miles through the Sacramento and San Joaquin valleys. More than 100,000 wells, most unmetered, draw from this aquifer, which scientists say has been depleted by 125 million acre-feet over the last century.
That’s enough to fill Lake Mead in Nevada, the nation’s largest reservoir, 4½ times.
The immediate impact can be seen in heavily farmed areas of the Central Valley, which, in the words of Bettina Boxall of the Los Angeles Times, “are deflating like a tire with a slow leak.”
In the long term, say scientists, even deeper wells in the Central Valley will no longer be productive, and farmers will be forced to allow additional millions of acres to go fallow.
As Walter Prescott Webb foresaw, it would be the inevitable triumph of the desert.