Water under pressure

Natasha Gilbert, Nature.com (March 13, 2012)

A UN analysis sets out global water-management concerns ahead of Earth Summit.

Water should be at the top of the agenda for the Earth Summit in Rio de Janeiro, Brazil, in June, a United Nations report urges.

The fourth World Water Development Report by the UN Educational, Scientific and Cultural Organization (UNESCO), launched at the World Water Forum in Marseilles, France, on 12 March, notes that industry, agriculture and booming urban populations are putting Earth’s water supplies under unprecedented pressure (see graphics). Hundreds of millions of people do not have access to clean water, leaving them at risk from waterborne diseases. Without prompt action to improve water-management policies, the report says, a global crisis looms.

Although the document contains a plethora of facts and figures, its authors argue that a lack of reliable data on water quality and usage has become a stumbling block for efforts to strengthen policies and enforce regulations. “You cannot properly manage something that you don’t know about,” says Olcay Ünver, coordinator of the UN World Water Assessment Programme. But closing the knowledge gap will be expensive: building a gauging station to measure a river’s flow can cost more than US$1 million, for example, and the expense of ongoing operation can be difficult for poor countries to justify. The report recommends increasing the use of remote-sensing technologies to monitor water quality, but notes that these will never completely replace information gathered on the ground.

The report also focuses on the burgeoning demands of agriculture. Food production already consumes more than two-thirds of the world’s extracted water, and food demand is expected to rise by 70% by 2050, owing to population growth. Research into improving crop yields and drought tolerance will help nations to meet needs while using water more efficiently.

The report concludes that policy-makers must balance the requirements of agriculture and industry with the need for sustainable sources of clean drinking water by developing integrated policies that satisfy all three sectors. Michel Jarraud, chairman of UN-Water — a grouping of 28 UN organizations including UNESCO — says that the group will tell leaders at the Rio summit that “the challenges, risks and uncertainties blocking the road to sustainable development require a collective response by the whole international community”.

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