Western US gets 40% of water from groundwater, which is being depleted and vulnerable to severe drought from climate change

In the Western US, 40 percent of the water comes directly from groundwater.  And aquifers in the southern tier of the West are all expected to see decreases in recharge as the climate warms.

Already, groundwater is already being withdrawn from the aquifers of California’s Central Valley, the central and southern portions of the High Plains and Arizona’s San Pedro faster than the groundwater is being recharged.

To synthesize existing knowledge and predict how climate change would affect western groundwater, Meixner gathered 16 experts in climate change and in hydrology of the western U.S.

he San Pedro aquifer in southeastern Arizona is one example of an aquifer where the human use of groundwater will increasingly outstrip recharge as the climate warms, the researchers report. Much of the San Pedro’s current recharge comes from mountain-system recharge, which the scientists expect will dwindle as more precipitation falls in the mountains as rain rather than snow and as the region dries.

When more groundwater is pumped than is replaced by recharge, rivers can be sucked dry, as happened to the Santa Cruz River in Tucson, Meixner said. Once the Santa Cruz flowed year-round; now in Tucson the river has water only after heavy rains.

Irrigation in the Amargosa Desert on the California/Nevada border uses water from the Death Valley Regional Aquifer. Credit: Courtesy of David Stonestrom/U.S. Geological Survey

“What you would expect to see is that climate change will exacerbate problems in the Southwest on the recharge end,” Meixner said.

“Our study reveals that the western U.S. needs to redouble efforts to manage water resources to maximize benefits to individuals and society,” he said. “We can’t be wasting water.”

Thomas Meixner, Andrew H. Manning, David A. Stonestrom, Diana M. Allen, Hoori Ajami, Kyle W. Blasch, Andrea E. Brookfield, Christopher L. Castro, Jordan F. Clark, David J. Gochis, Alan L. Flint, Kirstin L. Neff, Rewati Niraula, Matthew Rodell, Bridget R. Scanlon, Kamini Singha, Michelle A. Walvoord. Implications of projected climate change for groundwater recharge in the western United States. Journal of Hydrology, 2016; 534: 124 DOI: 10.1016/j.jhydrol.2015.12.027

“How climate change may lead to depletion of western US groundwater.” ScienceDaily, 17 February 2016.

MIT physicist, climate expert, and author Joe Romm says:  If we don’t take far stronger action on climate change, then here is what a 2015 NASA study projected the normal climate of North America will look like. The darkest areas have soil moisture comparable to that seen during the 1930s Dust Bowl.

rcp8.5_soilmoisture-1

Just the last 12 months have seen headlines like these: “Worst drought in 40 years puts more than 2 million people in Central America at risk” and “Drought Reduces Mexico’s Agricultural Production by 40%.” Of course you probably haven’t seen those stories, since most major U.S. media outlets have been too busy covering brutal droughts right here at home.

For a similar reason, there had been little reporting at the time on what one expertcalled perhaps “the worst long-term drought and most severe set of crop failures since agricultural civilizations began in the Fertile Crescent,” from 2006 to 2010. The 2015study, “Climate change in the Fertile Crescent and implications of the recent Syrian drought,” found that global warming made that Syrian drought two to three times more likely. “While we’re not saying the drought caused the war,” lead author Dr. Colin Kelley explained. “We are saying that it certainly contributed to other factors — agricultural collapse and mass migration among them — that caused the uprising.”

The study identifies “a pretty convincing climate fingerprint” for the Syrian drought, retired Navy Rear Admiral David Titley told Slate. Titley, also a meteorologist, said, “you can draw a very credible climate connection to this disaster we call ISIS right now.”

The Center for Climate and Security has been writing on the Syria-climate connection for over three years. Co-founder & Director Francesco Femia explained recently:

That drought, in addition to its mismanagement by the Assad regime, contributed to the displacement of two million in Syria. That internal displacement may have contributed to the social unrest that precipitated the civil war. Which generated the refugee flows into Europe.

And no, he’s not saying climate change “caused” the refugee crisis, nor am I. Major refugee crises are generally driven by multiple contributing factors. In this case, one of the factors appears to be climate change. In the coming years and decades, climate change will become a bigger and bigger factor.

During the U.S. Dust-Bowl era, some 3.5 million people fled the region. As I noted in “The Next Dust Bowl,” a 2011 Nature article reviewing the literature, “Human adaptation to prolonged, extreme drought is difficult or impossible. Historically, the primary adaptation to dust-bowlification has been abandonment; the very word ‘desert’ comes from the Latin desertum for ‘an abandoned place’.”

Nature-Dust-Bowl-small

But what scientists tell us we are doing to our climate will be much worse than the Dust Bowl of the 1930 — worse even than medieval U.S. droughts. Indeed, Lisa Graumlich, Dean of the University of Washington’s College of the Environment, notes that the Southwest drought from 1100-1300, “makes the Dust Bowl look like a picnic.”

Remember, the Dust Bowl itself was mostly contained to the 1930s, whereas multiple studies project that future Dust Bowls will be so-called “mega-droughts” that last for many decades — “at least 30 to 35 years,” according to NASA. Further, the 1930s Dust Bowl was regionally localized. As the NASA map above makes clear, we are on track to Dust-Bowlify much of the U.S. breadbasket and Southwest, and virtually all of Mexico and Central America.

Other recent research makes clear we would also turn large parts of the Amazon, Europe, and Africa into near-permanent dustbowls. And this would be “irreversible” on a timescale of centuries.

How bad were the medieval droughts? “Highly evolved societies collapsed and descended into warfare.” These are civilization-destroying, monster droughts. As thenews release notes, one of those droughts “has been tied by some researchers to the decline of the Anasazi or Ancient Pueblo Peoples in the Colorado Plateau in the late 13th century.”

And the post-2050 droughts we are foisting on future generations will be much worse — considerably drier and hotter. The dark brown area in the top chart corresponds roughly to the normal climate becoming “severe drought,” which of course means a great many years will be much drier. And the normal temperature will be some 9°F warmer.

Certainly, no country with rational leaders would risk self-destruction like this. Indeed, it is difficult to imagine how even a very wealthy country like America could “adapt” to such permanent Dust Bowls over vast areas of its most inhabited and arable land, at least the way most people think about adaptation today.

It seems likely most would adopt the traditional means humans have used to “adapt” when facing a brutal and very long-term drought — abandonment. Of course, we are a large country and we could in theory spend vast sums relocating our population. Also, we are the breadbasket for the world, which is to say we generate a lot of surplus food today — not to mention the 40 percent or so of food we waste. So we could probably avoid mass starvation in this country post-2050 with stringent enough measures.

But what of our poorer neighbors to the south? They will engulfed by near-permanent Dust Bowl or severe drought. And of course their coastal areas (and ours) will be trying to “adapt” to sea level rise of perhaps several feet by 2100. Again for all but the wealthiest coastal areas, the primary adaptation strategy will probably be abandonment.

Much of the population of Mexico and Central America — likely over 100 million people (Mexico alone is projected to have a population of 150 million in 2050!) — will be trying to find a place to live that isn’t anywhere near as hot and dry, that has enough fresh water and food to go around. They aren’t going to be looking south.

Now, from a purely moral perspective, if you burn down your neighbor’s house and farm, most people would say you have some obligation to house and feed them. So what should happen if one exceedingly wealthy country is the primary contributor to destroying the entire climate of another (relatively poor) country, which itself contributed only a tiny bit to that climate change? The answer seems straightforward — we do everything possible to help them.

But what will happen in the real world where this process occurs gradually over the coming decades for Mexico and Central America — at the same time United States is dealing with the self-inflicted destruction of its own livable climate?

The situation will be a humanitarian and security disaster of almost unimaginable dimensions compared to the current refugee crisis. As Femia and colleague Caitlin Werrell told Climate Progress, “If we worry about the security implications of refugee and migration flows in the future, we need to think about the problem in terms of prevention. Preventive security.”

It’s time to listen to the world’s top scientists and move quickly toward the supercheappath of avoiding climate catastrophe in the first place.