Wednesday, July 20, 2011

Averting a looming water crisis

Jul 20, 2011
It's time we redefine how we think of water, value it and use it

By Alex Prud'homme

FLOODS, tornadoes and other extreme weather have left a trail of destruction during the first half of this year. But this could be just the start to a remarkable year of bad weather.

Next up: drought. In the southern United States, 14 states are baking in blast-furnace conditions. Arizona, for example, is battling the largest wildfire in its history.

Climatologists call drought a 'creeping disaster' because its effects are not felt at once. Others compare drought to a python, which slowly and inexorably squeezes its prey to death. Climatologists disagree about what caused this remarkable dry-out. But there is little disagreement about the severity of the drought - or its long-term implications.

When I asked Professor Richard Seager, who analysed historical records and climate model projections for the south-west for the Lamont-Doherty Earth Observatory at Columbia University, if a perpetual drought was possible in that region, he replied: 'You can't really call it a drought because that implies a temporary change. The models show a progressive aridification. You don't say, 'The Sahara is in drought.' It's a desert. If the models are right, then the south-west will face a permanent drying out.'

Growing population has increased the burden on our water supply. There are more people on earth than ever, and in many places we are using water at unsustainable rates. Some of the world's biggest cities - Melbourne, Barcelona and Mexico City - have already suffered drought emergencies. Further drying could lead to new kinds of disasters.

Consider Perth, in Australia: Its population has surpassed 1.7 million while precipitation has decreased. City planners worry that unless drastic action is taken, it could become the world's first 'ghost city' - a modern metropolis abandoned for lack of water. Similar fates may await America's booming desert cities: Las Vegas, Phoenix or Los Angeles.

Our traditional response to desiccation has been to build hydro-infrastructure - dams, pipelines, aqueducts and levees. Many advocate building even bigger dams and ambitious plumbing projects, including one that calls for 'flipping the Mississippi', a scheme to capture Mississippi floodwaters and pipe them to the parched west.

But it is now widely believed that large water diversion projects are expensive, inefficient and environmentally destructive. The holy grail of water managers is to find a drought-proof water source.

Weather modification, or cloud seeding, is a particularly appealing ideal. When American chemists discovered that dry ice dropped into clouds produced snow, and that clouds seeded with silver iodide produced rain, they rhapsodised about ending drought. Under perfect conditions, weather modification can increase precipitation by 10 per cent to 15 per cent. China claims it produced 36 billion tonnes of rain a year between 1999 and 2006.

But critics question weather modification and its efficacy. The bottom line: Though evidence suggests it works to a limited extent, it is unlikely to produce a major supply of water soon.

For centuries, the ocean has been seen as a more promising water source. In 1961, then President John F. Kennedy said that 'if we could ever competitively, at a cheap rate, get fresh water from saltwater', it would 'dwarf any other scientific accomplishments'. By 2008, more than 13,000 desalination plants around the world produced billions of litres of water a day. But desalination, which is costly and environmentally controversial, has been slow to catch on in the US.

Recycled sewage offers an interesting, if aesthetically questionable, drinking source. (Supporters call it 'showers to flowers' while detractors condemn 'toilet to tap' schemes.) Plans for sewage recycling, which involves extracting and purifying the water, are slowly gaining acceptance. Windhoek, Namibia - one of the driest places on earth - relies solely on treated wastewater for its drinking supply. But the 'yuck factor' has led to a sharp debate about its merits.

Meanwhile, global demand for water is expected to increase by two-thirds by 2025, and the United Nations fears a 'looming water crisis'. To forestall a drought emergency, we must redefine how we think of water, value it and use it.

Singapore provides a noteworthy model: No country uses water more sparingly. In the 1950s, it faced water rationing, but it began to build a world-class water system in the 1960s. Now, 40 per cent of its water comes from Malaysia, while a remarkable 25 per cent to 30 per cent is provided by desalination and the recycling of wastewater. The rest is drawn from sources that include large-scale rainwater collection. Demand is curbed by high water taxes and efficient technologies, and Singaporeans are constantly exhorted to conserve every drop.

Most importantly, the nation's water is managed by a sophisticated, well-financed, politically autonomous water authority. As a result, Singapore's per capita water use fell to 154 litres a day this year, from 165 litres in 2003.

America is a much larger and more complex nation. But Singapore's example suggests we could do a far better job of educating our citizens about conservation.

We could take other basic steps: install smart meters to find out how much water we use, identify leaks (which drain off more than 4.5 trillion litres a year), use tiered water pricing to encourage efficiency, and promote rainwater harvesting and wastewater recycling on a large scale. And like Singapore, we could streamline our byzantine water governance system and create a new federal water office - a water czar or an inter-agency national water board - to manage the nation's supply in a holistic way.

There is no question that this will be an expensive, politically cumbersome effort. But as reports from New Mexico, Texas, Louisiana, Georgia and Florida make plain, business as usual is not a real option. The python of drought is already wrapped tightly around us, and in weeks - and years - to come it will squeeze us dangerously dry.

The writer is the author of The Ripple Effect: The Fate Of Fresh Water In The 21st Century.

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