A look into how development and climate change are leading to water conflicts.

The destruction of nearly 182,000 hectares and the displacement of a million people by the worst Californian fire-storms in decades are focussing attention on what may, over the next 50 years, become the most pressing environmental issue in the United States — the south-western States are drying up.

In one sense, the recent inferno has little to do with climate change or the pressure of human settlement. Southern California is arid by nature, the Santa Ana winds typically blow in the autumn, and wildfires are a natural part of the cycle. It is also true that this time the drought is more intense, the winds are stronger, the fires larger and their effects more keenly felt.

But the climate has had an impact. For almost seven years rain has been rare in southern California, and in much of the U.S. south-west. In 2004, the region did experience record rainfall and the desert bloomed with vegetation, but little or no rain has fallen since on the coastal and inland valleys behind Los Angeles and San Diego. The tinderbox-dry vegetation has become fuel, turning California’s usually blue skies black with smoke. The severity of the regional drought, coupled with climate change, population and developmental pressures, and the infrastructure for bringing water to the desert from the Rocky Mountains in the north operating well beyond its design capacity, could spell disaster.

Inter-State conflicts

Despite billions of dollars allocated to new water projects, scientists warn that the south-west is likely to be transformed by climate change, forcing adjustments in the economic and social order, perhaps triggering new inter-State conflicts for the control of diminishing water supplies from Texas to the Pacific.

In several recent studies, hydrologists have warned that the current drought may be a permanent condition. Climate change models uniformly project that the region will grow hotter and drier — some predicting average temperature increases of up to 6 degrees Celsius by the end of the century. One fear, highlighted by a gloomy report in the journal Science, is that the accelerating effects of global warming, coupled with the meteorological phenomenon La Nina developing in the Pacific, which heralds a dry winter, will intensify the drought in the short term and perhaps turn the region into a permanent dustbowl within 50 years.

New Mexico’s largest storage reservoir, Elephant Butte, is less than 50 per cent full, and flows into it are 54 per cent below average. The spectacular Lake Powell and Lake Mead reservoirs in Nevada and Arizona are depleted and may never be full again, according to projections — groundwater aquifers that sustain the lawns and pools of millions of desert dwellers from across the region are being rapidly drained.

Increasing average temperatures, earlier snow melting, widespread wildfires burning nearly 4.5 million hectares of land last year, as well as changes in animal habitation and vegetation, point to an increasingly stressed ecosystem. Farmers say they are planting less; ranchers are raising fewer head of livestock. In Arizona, the remarkable green “sky islands” that rise above the desert floor are being lost to higher temperatures.

Across much of the south-west, one of the fastest developing regions in the U.S., the change in weather patterns and long-term climate shifts is exacerbated by population pressure — more people demanding more water from dwindling supplies. Since the development of the west was contingent on the construction of great dams and reservoirs, the effects of seeing the water supply shrinking are unsettling.

One result is growing tension between seven States —Colorado, Wyoming, Utah, Nevada, New Mexico, Arizona, and California — that are all dependent on water allocations from the Colorado river. Last summer saw a substantial reduction in the Colorado’s water flow, which is fed by melting snow from the Rocky mountains. The situation, warns Kevin Trenberth, a hydrologist for the National Centre for Atmospheric Research, “is a situation that is going to cause water wars.”

Earlier this year, Nevada water engineers unveiled plans for a pipeline to serve the Las Vegas metropolis with groundwater that farmers on the Nevada-Utah border claim as their own. With wells already running low, regional farmers fear the gambling mecca will suck the area dry. At the same time, Utah plans to pipe water from deep aquifers to its own fast-developing cities — water that Nevadans claim is theirs under treaty.

Further south, in Texas, the terms of a 1944 U.S.-Mexico water settlement that guarantees water allocations south of the border are being put to the test amid the growing perception that water, not energy, will be the underlying cause of future conflict. In an editorial earlier this year, The New York Times described Mexican water allocations as a waste of resources. The U.S. Government has claimed its southern neighbour owes it water.

Mexico, which has less water per capita than Egypt, regards water as an issue of national security, and has accused the U.S. of irresponsibility by promoting regional growth as if there were no limit to supply. “I think the struggle for water will be the gravest problem of this century,” says Enrique Martinez, Governor of the State of Coahuila, which borders Texas.

With illegal immigration becoming a hot election issue, and the U.S. preparing a fence along the length of the border, Mexican officials complain the U.S. is exacerbating border issues with its thirst. One solution — to build new reservoirs — is undermined by the fact that current reservoirs are not refilling. Lake Powell, which is at 50 per cent capacity, will take 20 years of average flow from the Colorado to refill — but no one is predicting that the river will be restored to normal flow.

A dangerous bet

The arid south-west has long operated in the hope that dry years will give way to wet — that one or two good hurricanes will restore water reserves. But clear evidence of rapid climate change makes this a dangerous bet. Theories of how to alleviate the situation run from massive desalination plants to simply building a pipeline down from Canada (States bordering the Great Lakes — which are themselves depleted — are mulling over a pact to protect lake water from “outside exploitation”).

At the least, residents of the west may have to accept that the pioneers’ dream of creating a verdant land like the country they left behind in the east is unsustainable. The lifestyle of millions of Las Vegans, with lush lawns, fountains, pools and golf courses, may not last. As Pat Mulroy, head of the Southern Nevada Water Authority, recently told The New York Times: “The people who move to the west today need to realise they’re moving into a desert. If they want to live in a desert, they have to adapt to a desert lifestyle.”

Along the banks of the Rio Grande, Apaches invoked the rain gods with dances, and Spanish conquistadors of the 16th century offered prayers to San Isidro, patron saint of farmers. With the forces of climate change unleashed, and fires taking hold from San Diego to Los Angeles, prayer may still be an important component in the region’s future planning. — ©Guardian Newspapers Limited, 2007

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