Now we're reaching "peak water"
MATT CAWOOD
19 Jun, 2010 04:00 AM
THE planet is far from running out of water, but many countries are beginning to exhaust the local supplies they need to maintain agricultural productivity and ecosystem health.
Welcome to the age of “peak water”.
“Peak oil” describes the peaking in discovery of extractable oil, followed by a decline - a theory that is gaining credibility, with recent forecasts suggesting that the peak could occur sometime between now and 2030.
But international water expert Peter Gleick believes that unsustainable use of water is “far more worrisome, and far more difficult to evaluate”, than limits on resources such as petroleum.
Dr Gleick says that because of water’s ubiquity, “peak water” isn’t the same thing as peak oil, but he believes that it’s a useful phrase to describe the effect humans are having on many critical sources of water.
“I believe that a substantial fraction of the global food supply is produced with unsustainable groundwater use, in regions where peak non-renewable water limits have already been exceeded,” said Dr Gleick, an international water expert and founder of the Pacific Institute in California.
“If we do not figure out how to produce food from renewable and sustainable water resources, the food supply of hundreds of millions of people, or even more, may be at risk.”
Julian Cribb, author of the soon-to-be-released book “The Coming Famine”, said dwindling water resources aside, a major conflict between the water needs of agriculture and cities is emerging.
The world’s irrigated agriculture currently uses about 2500 cubic kilometres of water - 70 per cent of the water used by people - to produce 45 per cent of the world’s food.
Urban areas currently use about 1300 cu km. With a growing population moving towards greater urbanisation, the world’s cities are expected to demand about 2500 cu km by 2050, Mr Cribb.
Freshwater supplies already over-extended, and climate change is melting glaciers and increasing evaporation rates, Mr Cribb said. So where does the extra water come from?
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