Value ecosystems not just crops when managing water use, says UN report

13th Mar 2012

A new the United Nations Environment Programme report prepared by the Stockholm Environment Institute at the University of York urges policymakers and planners to think about ecosystem services, not just agricultural crop yields, in determining the most ‘productive’ uses of water.

The report, released at the World Water Forum in Marseille, France, argues that water productivity gains can only be made when we recognise the multiple benefits of water to generate ecosystem services. This understanding is crucial to managing water resources more sustainably and efficiently to balance demands and benefits to livelihoods, agriculture and environment.

Increasing water productivity and efficiency is a key concern for policymakers in many parts of the world, especially as rising incomes and changing diets are set to increase the demand on water resources that are already under pressure.

The United Nations Environment Programme report, Releasing the Pressure: Water Resource Efficiencies and Gains for Ecosystem Services, urges policymakers and resource managers to shift from the traditional focus on water productivity per unit of agricultural yield (“more per crop drop”), to a broader view that includes ecosystems services.

Such an approach would consider the value of water regulation and purification, pollination, erosion control and other ecosystem services that can be adversely affected when water is siphoned off from rivers or streams, or drained from marshes, for agricultural use.

“Assessing water productivity narrowly – for example, by simply looking at crop, fodder and forest produce – will continue to under-value the role of water for wider society and the economy,” says UN Under-Secretary-General and UNEP Executive Director Achim Steiner.

“Recognising the wider benefits generated by water, for example nutrient flows, cooling, providing habitats, and other supporting and regulating ecosystem services, is the aim of our work,” he adds. “Water may soon be a critically restricted resource for a growing number of people. In just over three months, world governments will meet for the UN Conference on Sustainable Development (Rio+20). This report addresses an important issue for future sustainable development: how to enhance the productive and equitable use of water for multiple needs.”

The report uses case studies from Africa and Asia to demonstrate how some of the pressure on limited water resources can be managed with existing techniques, such as soil and water conservation, minimum tillage and rainwater harvesting.

Such techniques could sustainably improve the productivity of water used in rainfed agriculture in Africa, Eastern Europe and Central Asia, which provides 60 per cent of the world’s cereal crops, the study notes.

Closing current yield caps to within 95 per cent of potential yields in rainfed agriculture could increase grain production by 58 per cent, while maintaining current levels of water use and allowing surrounding landscape water flows to sustain ecosystems services.

The report, which is structured around a set of 10 key messages, encourages practitioners in agricultural planning and management, land-use planning, forestry, biofuels and natural resource management to explore these issues in their local contexts.

It also urges them to redefine what they consider to be ‘efficient’ or ‘productive’ water use.

“A narrow definition of ‘water productivity’ considers only the value of agricultural produce, but doesn’t put a price on lost drinking water, reduced fish populations, parched pastures, or shrinking groundwater reservoirs,” says Jennie Barron, a research fellow at SEI’s centre at the University of York, U.K., who wrote the report with Patrick Keys, an SEI associate consultant based in Seattle, Washington (U.S.).

“Improving water management to reflect multiple needs and multiple uses is crucial to sustaining water’s many benefits to human well-being, societies and economies,” says Patrick Keys. “Many ecosystem services that underlie people’s livelihoods draw on the same water resources used for agriculture: wetlands that provide reeds, fish and rice; forests that supply timber, firewood and game. In addition, water is needed to support and regulate important functions such as nutrient transport, vapour flow and sediment flows.”

The report is accompanied by a policy brief summarising the key points. In addition, UNEP is launching a set of three manuals to enable policymakers and water practitioners to incorporate ecosystems approaches in the management of water resources.

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