Nearly one billion people worldwide are malnourished. The majority of these people live in developing countries, where increasing water scarcity complicates efforts towards food self sufficiency. Huge amounts of water are needed to produce more food and eradicate hunger among increasing populations. How should this need be met?

Each person needs over 4,000 litres of water each day to produce enough food for a healthy diet. Farmers face increasing competition for water from industry, forestry, fibre production and fisheries. However, most water management policies only consider liquid ‘blue water’, which is the water available in rivers, lakes and aquifers. This neglects the invisible ‘green water’, for example the naturally infiltrated rain accessible as the soil moisture taken up by plants. Research in a policy brief from the Stockholm International Water Institute, Sweden, shows that when green water is considered as well, there is plenty of water to meet agricultural needs, even in hunger-stricken and poverty-stricken areas.

The research shows:

• Over 60 percent of the world’s food is produced from green water. In sub-Saharan Africa this figure reaches 95 percent.
• Changes in land use affect green water flows. This determines the generation of runoff and therefore the blue water flows available downstream.
• Further increases in withdrawal from blue water sources may trigger a massive ecosystem collapse and cause social unrest, especially in coastal areas.
• Reducing the loss of green water through non-productive evaporation and making it accessible to plants as productive transpiration (so-called vapour shift) has the potential to supply large amounts of water for forestry products, grain farming and market food needs.
• Climate change will make the management of water even more difficult, with increased frequency of water-related events such as dry spells, droughts and floods.

Achieving the Millennium Development Goals (MDGs) will require new policies for coping with the dry climates in most developing countries. The central issue is how to manage water for all the different functions for which it is needed. An important step is to distinguish between blue water and green water flows, by changing the current view of the world’s water resources.

The limited current approaches to increasing demands for water will not be enough to eradicate hunger, especially in areas with growing populations. The link between hunger, poverty and water management must be made clearer, especially within the MDGs. The research recommends an approach that:

• accepts there is not enough blue water left to meet competing food, water and environment needs
• raises awareness of the difference between blue water in rivers and aquifers and green water in the soil
• recognises the importance of both types of water in agriculture
• promotes the potential of green water to contribute to global food production
• introduces both green water issues and land-use issues into water resources management practices and governance
• broadens approaches to water management so that it maximises benefits to agricultural communities, particularly in water-scarce regions.

Source(s):
‘Rain: The Neglected Resource’, Swedish Water House, Policy Brief, No. 2, by Malin Falkenmark and Johan Rockström, 2005 Full document.

Funded by: The Stockholm International Water Institute; The Stockholm Environment Institute

id21 Research Highlight: 31 March 2006

Further Information:
Malin Falkenmark
Stockholm International Water Institute
Drottninggatan 33
SE-111 51 Stockholm
Sweden

Tel: +46 8 522 139 60
Fax: +46 8 522 139 61
Contact the contributor: Malin.Falkenmark@siwi.org

Stockholm International Water Institute, Sweden

Other related links:
'How can dry countries manage water shortages?'

'The value of rainfed agriculture in a world short of water'

'A ‘blue revolution’ for African agriculture'

'Is trade in virtual water a solution for water-scarce countries?'

See id21's links on water