Global Warming Hits Southwest
The polar bear on its shrinking ice floe has become the urgent icon of global warming and runaway climate change. Even the flat-earther in the White House now concedes that the magnificent bears may be doomed to extinction as the sea ice melts and the Arctic Ocean is transformed into open blue water for the first time in millions of years. Humanity's "great geophysical experiment," as the oceanographer Roger Revelle long ago characterized the steeply rising curve of carbon dioxide emission, has knocked nature off its Holocene foundations in the circumpolar lands.
But the Arctic is not the only theater of spectacular and unequivocal climate change, nor are the polar bears the only heralds of a new age of chaos. Consider, for example, some of Ursus maritimus's distant relatives: the black bears that forage happily but ominously in the fabled Chisos Mountains of Texas's Big Bend National Park. They may be the messengers of an environmental transformation in the Borderlands almost as radical as that taking place in Alaska or Greenland.
While hiking en route to Emory Peak on a preternaturally warm day in January 2002, with my mind still haunted by the apocalyptic images of the previous September, I made the nodding acquaintance of an antic and harmless young bear in a trail camp. Apparitions of bears are always slightly magical, and I presumed the encounter was an affirmation of a still largely unspoiled wilderness. In fact, as I was startled to learn from a ranger the next day, the young bear was, so to speak, a mojado -- the offspring of recent undocumented immigrants from the other side of the Rio Grande.
Black bears had been common in the Chisos when it was the quasi-mythical redoubt of Mescalero Apache and Comanche raiders in the seventeenth and eighteenth centuries, but ranchers relentlessly hunted them to extinction in the early twentieth century. Then, almost miraculously in the early 1980s, bears reappeared amid the madrone and pine of Emory Peak. Astonished wildlife biologists surmised that the bears had migrated from the Sierra del Carmen in Coahuila, swimming the Rio Grande and crossing forty miles of furnace-hot desert to reach the Chisos, a promised land of docile deer and abundant garbage.
Like the jaguars that have re-established themselves in the border mountains of Arizona in recent years or, for that matter, the blood-sucking chupacabra of norteÃƒÂ±o folklore who has reputedly been seen in the suburbs of Los Angeles, the black bears are part of an epic migration of wildlife as well as people al otro lado. Although no one knows exactly why the bears, big cats and legendary vampires are moving northward, one plausible hypothesis is that they are adjusting their ranges and populations to a new reign of drought in northern Mexico and the US Southwest.
The human case is clear-cut: Abandoned ranchitos and near-ghost towns throughout Coahuila, Chihuahua and Sonora testify to the relentless succession of dry years -- beginning in the 1980s but assuming truly catastrophic intensity in the late 1990s -- that has pushed hundreds of thousands of poor rural people toward the sweatshops of Ciudad JuÃƒÂ¡rez and the barrios of Los Angeles.
In some years, "exceptional drought" has engulfed the entire Plains from Canada to Mexico; in other years, crimson conflagrations on weather maps have crept down the Gulf Coast to Louisiana or crossed the Rockies to the interior Northwest. But the semipermanent epicenters have remained the basins of the Colorado and Rio Grande rivers, as well as northern Mexico.
By 2003, for example, Lake Powell had fallen by nearly eighty feet in three years, and crucial reservoirs along the Rio Grande were barely more than mud puddles. The Southwestern winter of 2005-06, meanwhile, was one of the driest on record, and Phoenix went 143 days without a single drop of rain. Rare interruptions in the drought, like the Noachian monsoon of last summer (parts of El Paso received an incredible thirty inches of rain), have been insufficient to adequately recharge aquifers or refill reservoirs, and in 2006 both Arizona and Texas reported the worst drought losses to crops and herds in history (about $7 billion altogether).
Persistent drought, like melting ice, rapidly reorganizes ecosystems and transforms entire landscapes. Without sufficient moisture to produce protective sap, millions of acres of pinyon and ponderosa pine have been ravaged by plagues of bark beetles; these dead forests, in turn, have helped to kindle the firestorms that have burst into the suburbs of Los Angeles, San Diego, Phoenix and Denver, as well as destroyed part of Los Alamos. In Texas the grasslands have also burned -- nearly 2 million acres in 2006 alone -- and as topsoil blows away, prairies are reverting to desert.
Some climatologists have not hesitated to call this a "mega-drought," even the "worst in 500 years." Others have been more cautious, not yet sure whether the current aridity in the West has surpassed the notorious thresholds of the 1930s (the Dust Bowl in the southern Plains) or 1950s (devastating drought in the Southwest). But the debate is possibly beside the point: The most recent and authoritative research finds that the "evening redness in the West" (to invoke the portentous subtitle of Cormac McCarthy's Blood Meridian) is not simply episodic drought but the region's new "normal weather."
In startling testimony before the National Research Council last December, Richard Seager, a senior geophysicist at the Lamont Doherty Earth Observatory of Columbia University, warned that the world's leading climate modelers were cranking out the same result from their super-computers: "According to the models, in the Southwest a climate akin to the 1950s drought becomes the new climate within the next few years to decades."
This extraordinary forecast -- "the imminent drying of the U.S. southwest" -- is a byproduct of the monumental computational effort that has been mounted by nineteen separate climate models (including the flagship outfits at Boulder, Princeton, Exeter and Hamburg) for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).
The IPPC, of course, is the supreme court of climate science, established by the United Nations and the World Meteorological Organization in 1988 to assess research on global warming and its impacts. Although President Bush now grudgingly accepts the IPCC warning that the Arctic is rapidly melting, he has probably not yet registered the possibility that his ranch in Crawford might someday become a sand dune.
Climatologists studying tree rings and other natural archives have long been aware that the 1922 Colorado River Compact, which allocates water to the rapidly urbanizing oases of the Southwest, is based on a twenty-one-year record (1899-1921) of river flow that, far from being an average, is actually the wettest anomaly in at least 450 years. More recently, they have gained an understanding of how persistent La NiÃƒÂ±as (cold episodes in the eastern equatorial Pacific) can interact with warm spells in the subtropical North Atlantic to generate droughts in the Plains and Southwest that can endure for decades.
But, as Seager emphasized in Washington, the IPCC simulations point to something very different from the arid episodes catalogued in Lamont's North American Drought Atlas (a state-of-the-art compendium of tree-ring records from 2 BC to the present). Unexpectedly, it is the base climate itself, not just its perturbations, that is changing.
Moreover, this abrupt transition to a new, more extreme climate ("unlike any in the last millennium, and probably in the Holocene") arises not out of fluctuations in ocean temperatures but from "changing patterns of atmospheric circulation and water vapor transport that arise as a consequence of atmospheric warming." In a nutshell, the dry lands will become more arid, and the humid lands, wetter. And the drying of the West will be accompanied by blast-furnace heat: IPCC's new report includes an astonishing prediction that temperatures in the American West will increase by an average of nine degrees Fahrenheit by the end of this century.
La NiÃƒÂ±a events, Seager added, will continue to influence rainfall in the Borderlands, but building from a more arid foundation, they could produce the West's worst nightmares: droughts on the scale of the medieval catastrophes that contributed to the notorious collapse of the complex Anasazi societies at Chaco Canyon and Mesa Verde during the twelfth century. (To make the bad news from the super-computers even worse, enhanced aridity is also forecast for much of the Mediterranean and the Near East, where epic drought is a well-known historical synonym for war, population displacement and ethnocide.)
Yet mere scientific pronouncement, even to the thunder of nineteen unanimous climate models, is unlikely to cause much of a flutter in golf-course suburbs of Phoenix, where luxury lifestyles consume 400 gallons of water per capita each day. Nor will it stop the bulldozers shaping monstrous strip suburbs of Las Vegas (a projected 160,000 new homes) along US 93 all the way to Kingman, Arizona. Nor, despite possible pumping out of the vast Ogallala Aquifer, the underground water resource lying under eight states in the Great Plains, will it prevent Texas from doubling its population by 2040.
Despite a lot of recent sloganeering about "smart growth" and intelligent water use, desert developers are still stamping out burbs in the same "dumb," environmentally inefficient mold that has blighted Southern California for generations. The trump card of the free-enterprise Southwest, moreover, is that the majority of the water stored within the Colorado River and Rio Grande systems is still dedicated to irrigated agriculture.
Even if "peak water" has now come and gone, desert sprawl can sustain itself in the medium run by killing cotton and alfalfa, while the big growers stay rich selling their federally subsidized water to thirsty suburbs. A prototype of this restructuring is already visible in California's Imperial Valley, where San Diego has been aggressively buying water entitlements. As a result, an attentive air traveler will notice a recent increase in dead squares within the Valley's emerald checkerboard of alfalfa and melons.
More futuristically, there is also the "Saudi" option. Steve Erie, a University of California, San Diego, professor who has written extensively about water politics in Southern California, told me that desert developers in the Southwest and Baja California are confident that they can keep the population boom well-watered through the conversion of seawater. "The new mantra of the water agencies, of course, is incentivizing conservation and reclamation, but rapacious developers are casting covetous eyes at the Pacific Ocean and the alchemy of desalination heedless of the pernicious environmental consequences."
In any event, Erie emphasizes, markets and politicians will continue to vote for the kind of rampant, high-impact suburbanization that now paves and malls thousands of square miles of the fragile Mojave, Sonora and Chihuahua deserts. States and cities, of course, will compete more aggressively than ever over water allocations, "but collectively the growth machines have the power to wrest water from other users."
As water becomes more expensive, the burden of adjustment to the new climatic and hydrological regime will fall on subaltern groups like farmworkers (jobs threatened by water transfers), the urban poor (who could easily see water charges soar by $100 to $200 per month), hardscrabble ranchers (including many Native Americans) and, especially, the imperiled rural populations of Northern Mexico.
Indeed, the ending of the age of cheap water in the Southwest -- especially as it may coincide with the end of cheap energy -- will accentuate the region's already high levels of class and racial inequality as well as drive more emigrants to gamble with death in dangerous crossings of the border deserts. (It takes little imagination, moreover, to guess the Minutemen's future slogan: "They are coming to steal our water!")
Conservative politics in Arizona and Texas will become even more envenomed and ethnically charged, if that is possible. The Southwest is already sown everywhere with violent nativism and what can only be described as proto-fascism: In the droughts to come, they may be the only seeds to germinate.
As Jared Diamond points out in his recent bestseller Collapse, the ancient Anasazi did not succumb simply to drought but rather to the impact of unexpected aridity upon an over-exploited landscape inhabited by people little prepared to make sacrifices in their "expensive lifestyle." In the last instance, they preferred to eat one another.