Have we reached peak water?

We all know about peak oil, but peak water? Water expert Peter Gleick of the Pacific Institute poses the possibility that, despite the vast amounts of water on “Planet Ocean,” we may be running out of sustainably managed water.

What is sustainably managed water? This term relates to the way we use, manage and abuse the fresh water that is regularly replenished by precipitation. In several places in the world, such as the southwestern United States and China, so much fresh water is withdrawn that rivers have actually dried up before they reach the sea.

“Humans already appropriate over 50 per cent of all renewable and accessible freshwater flows,” said Gleick, “and yet billions still lack the most basic water services.” It could be difficult in many places to find additional fresh water to bring the level of water services to a higher standard for those without sufficient water.

People are increasingly turning to aquifers to supply water, but the deeper aquifers are not replenished from precipitation, at least not in the short term, so cannot be classed as sustainable. Wells are drilled deeper and deeper to find water, increasing the cost and energy used to supply water.

Energy use, water and climate change are intimately linked.

Water transportation, storage and treatment are major users of energy and producers of greenhouse gases. In California, the source of much of North America’s vegetables and fruits, water accounts for about 19 per cent of the state’s electricity use.

Since irrigation is a major user of energy, Gleick points out that policies that lead to reduced water consumption could address climate change more efficiently than requiring businesses and households to use less energy.

“Some of the cheapest greenhouse-gas emission reductions available seem to be not energy-efficiency programs, but water-efficiency programs,” said Gleick.

Water efficiency helps fight global warming, but global warming is also reducing rainfall and causing people to dig deeper wells, requiring more energy for pumping.

In China, drought is affecting the northern wheat belt and nearly four million people are without proper drinking water. After declaring an emergency “rarely seen in history,” the government said it plans to send cloud-seeding rockets into the air to encourage rain, and to redirect portions of the Yangtze and Yellow rivers.

Many regions of China fit into Gleick’s definition of peak water (for more information on this, visit www.worldwater.org.)

“China is an example where (water) problems come together in the worst ways on the planet,” said Gleick. “Water resources are over-allocated, over-used, and grossly polluted by human and industrial waste.”

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Source: Canada.com