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Where Catastrophic Droughts and Floods Are Bound to Happen in the U.S.

Many Americans might not realize it, but the country is headed for a brutal reality check in terms of access to clean, cheap water. Climate change's amplifying effects are turning dry regions into virtual deserts and wet ones into flood zones, setting the stage for a horde of "water-related catastrophes, including extreme flooding, drought, and groundwater depletion," warn scientists at UC Irvine.

The aguapocalypse is "all but certain" to fall on America, as well as many other parts of the world, and could occur as soon as "decades" from now, say the same researchers. And from where are they drawing these grim conclusions? Well, like all scientists who study the climate, they just make them up – kidding! Actually they're monitoring sophisticated instruments designed by the nation's finest engineers. NASA maintains a pair of satellites for its GRACE mission that track the global groundwater supply, and over the years they've developed quite a thorough understanding of the thirst pains the planet could soon suffer.

This GRACE-based map shows the rate that groundwater supplies – which worldwide are estimated to compose half of our drinking water – have changed from 2003 to 2012. The way the satellites snag this data is rather neat; they sample tiny shifts in the earth's gravity, and from those changes deduce how much H2O is hiding beneath the soil. There's nothing neat about how vast portions of the country are drying out, though, which are shown on this map in angry red that indicates the historical "freshwater storage rate of change":

Nor is it cool how tons more water (shown in blue) is grouping around the Missouri River Basin, the country's midsection that's recently seen bad flooding, like this June 2011 deluge in Rock Port, Missouri:


(Lane Hickenbottom / Reuters)

The scientists at UC Irvine and NASA used this satellite data to pinpoint where in the U.S. the risk of imminent parching is highest. The answer is many, many places, they write:

Using GRACE data, the researchers were able to identify several water ‘hotspots’ in the United States, including its key food producing regions in 1) California’s Central Valley, and 2) the southern High Plains aquifer; a broad swath of the southeastern U. S. that has been plagued by persistent drought, including 3) Houston, Texas, 4) Alabama, and 5) the Mid-Atlantic region; and 6) the flood-prone upper Missouri River basin. They also noted that since 2003, the wetter, northern half of the U.S. has become wetter, while the drier, southern half has become drier.

So once again, the most current climate science indicates that the worst near-term threat is water scarcity, not rising sea levels. This aggravation of the watery haves and have-nots is set to only worsen in coming decades if humanity doesn't act fast – pump more energy into monitoring water reserves and establish better-coordinated conservation measures. The alternative is to ignore the problem, which the researchers note is a great way of ushering in a new age of chaos Their assessment for the future is a delightful blend of optimism and creeping dread:

According to Famiglietti and Rodell, without coordinated and proactive management, the aquifers supplying the Central Valley and the southern High Plains with water for irrigation will deplete their groundwater reserves, perhaps within decades, putting the nation’s food supply at considerable risk. Meanwhile, if sufficient measures are not taken, the upper Missouri River basin will experience extensive flood damage. The authors state that using GRACE, groundwater supplies can now be better managed, while the lead-time for flood and drought predictions could be substantially increased, potentially saving hundreds of millions of dollars and countless lives in the process.

Map courtesy of NASA Earth Observatory

John Metcalfe is a staff writer at The Atlantic Cities. All posts »

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