Megadrought

Long-term weather pattern prediction is among the most complicated of scientific challenges. Not only do you have determine past cycles and possible explanations for the phenomena – by looking at tree ring growth and examining layers of soil settling – but new factors (like factoring in the impact of greenhouse gasses) have to be considered as well. As land dries and cracks across the west, as fires rage stronger and water supplies dwindle, planning for the future becomes less of an academic inquiry than a vital survival necessity.

For example, close to 40 million people rely on the Colorado River for both potable and irrigation water needs. From Los Angeles to Las Vegas, or Phoenix to San Diego and the farmlands surrounding these urban sprawls, the Colorado River is life itself. 80% of our nation’s winter vegetable crop depends on water resources in this region.

A recent study by University of California-Irvine and NASA researchers is hardly reassuring: “The researchers analyzed satellite measurements of the Earth's mass and found that the region's aquifers had undergone a much-larger-than-expected drawdown over the past decade—the region's farms and municipalities responded to drought-reduced flows from the Colorado River by dropping wells and tapping  almost 53 million acre-feet of underground water between December 2004 and November 2013—equal to about 1.5 full Lake Meads, drained off in just nine years, a rate the study's lead researcher, Jay Famiglietti, calls ‘alarming.’” MotherJones.com, September 13^th. If those wells/aquifers go dry, the consequences are devastating.

Just looking at the water table at Lake Mead is depressing, but between global climate change and normal cyclical patterns of drought, what might have been a fairly short-lived dry spell could grow to well-beyond a generation… perhaps creating permanent desertification in what is currently one of the most important agricultural regions in the United States. The relevant credible research in this arena is anything but reassuring.

For example, another study – from Cornell University, the University of Arizona and the U.S. Geological Survey and just published in the Journal of Climate from the American Meteorological Society – tells us: "In the US Southwest, for instance, state-of-the-art climate model projections suggest the risk of a decade-scale megadrought in the coming century is less than 50%; our analysis suggests that the risk is at least 80%, and may be higher than 90% in certain areas. The likelihood of longer lived events (> 35 years) is between 20% and 50%, and the risk of an unprecedented 50 year megadrought is non-negligible under the most severe warming scenario (5-10%). These findings are important to consider as adaptation and mitigation strategies are developed to cope with regional impacts of climate change, where population growth is high and multidecadal megadrought—worse than anything seen during the last 2000 years—would pose unprecedented challenges to water resources in the region.”

As bad news accelerates, it is puzzling why we don’t already have operational desalinization plants all up and down the California coast.  Israel and Australia have spent billions to create these plants to quench local water needs, but older technologies tend to use too much energy (not to mention the issue of salt discharges into the ocean). But with newer processes, like “forward osmosis,” energy requirements are dropping like a stone. And perhaps, at least when it comes to average consumer needs, California’s time to shine in this space is now.

“Since the 1970s, California has dipped its toe into ocean desalination --talking, planning, debating. But for a variety of reasons -- mainly cost and environmental concerns-- the state has never taken the plunge.

“Until now… More than 300 construction workers are digging trenches and assembling a vast network of pipes, tanks and high-tech equipment [in Carlsbad, California] as three massive yellow cranes labor nearby… The crews are building what boosters say represents California's best hope for a drought-proof water supply: the largest ocean desalination plant in the Western Hemisphere. The $1 billion project will provide 50 million gallons of drinking water a day for San Diego County when it opens in 2016…

“Fifteen desalination projects are proposed along the coast from Los Angeles to San Francisco Bay. Desalination technology is becoming more efficient. And the state is mired in its third year of drought. Critics and backers alike are wondering whether this project in a town better known as the home of Legoland and skateboard icon Tony Hawk is ushering in a new era.” San Jose Mercury News, May 29^th. We can expect to see water rates rising, maybe by 20% or more, but the alternative of living without water is unacceptable.

For farmers, this lifts some of the pressure on their own supplies, but there will still be serious shortfalls that will keep agricultural output down and farm products increasingly expensive for the foreseeable future. We need new irrigation techniques (thank you Israel and Chile for your pioneering efforts) and drought-resistant crops big time. These problems are likely only to get worse, so prioritization on such water-related projects won’t just impact the commercial viability of the entire region, it may well define whether or not massive populations and industries can remain here.

 I’m Peter Dekom, and this is a lesson for all of America, even where flooding has replaced drought as the necessary consequence of global warming.