Temps de lecture :3 minutes
Today’s agriculture uses 70 percent of all fresh water withdrawals globally, and up to 95 percent in several developing countries, to meet the present food demand. To keep up with growing food demand and shifting diets over the next 30 years, FAO estimates that the effective irrigated area will need to increase by 34 percent in developing countries, and 14 percent extra water needs to be withdrawn for agricultural purposes. It should also be remembered that irrigated agriculture provides some 40 percent of the global food supply on 20 percent of cultivated land.
Historically, large-scale irrigation projects have played a major role in ensuring food supply for a rapidly growing population, and in contributing to poverty alleviation by providing food security, protection from flood and drought, and expanded opportunities for employment. In many cases, irrigated agriculture has been a major engine for economic growth and poverty reduction.
In arid and semi-arid regions, where water scarcity is almost endemic, groundwater has played a major role in meeting domestic and irrigation demands. In many regions, massive use of groundwater has been made for some time for irrigation. However, groundwater mining and the
lack of adequate planning, legal frameworks and governance have opened a new debate on the sustainability of the intensive use of groundwater resources.
Most countries in the Near East and North Africa suffer from severe water scarcity, as do countries such as Mexico, Pakistan, South Africa, and large parts of China and India. Irrigated agriculture, which represents the bulk of the demand for water in these countries, is also usually
the first sector affected by water shortage and increased scarcity, resulting in a decreased capacity to maintain per capita food production while meeting water needs for domestic, industrial and environmental purposes.
Thus, growing scarcity and competition for water stand as major threats to future advances in food security and poverty alleviation. In semi-arid regions, increasing numbers of the rural poor are coming to see entitlement and access to water for food production, livestock and domestic purposes as critical as access to primary health care and education. There is thus need to also focus on issues relating to equity and rights in access to water.
Typically only 30 to 50 percent of the water diverted for irrigation is actually used by crops. Best management practices and technology for irrigated and rainfed farming systems (not only limited to water-related practices) have still to play a significant impact on the productivity of water. Trade has not been fully explored in the optimization of water use. Therefore, within this sector, the wider range of options to cope with water scarcity exists.
The extent to which agriculture has been responsible for generating water scarcity and using/degrading some of the world’s highest quality surface and groundwater for marginal output is not disputed. What is often ignored is the management of agricultural water to open up more options for reallocation. Much of the international debate on water scarcity has to do with the chronic lack of water supply and sanitation services (which consume a fraction of renewable resources) when it is agricultural water that offers most scope to alleviate stress. The fact that water is instrumental in many aspects of rural development has been stressed in FAO’s recent reform proposals, and a Natural Resources Department in which water resources development, control and management is centred, has now been established. Consequently there is need for a more explicit water programme to leverage water expertise across the Organization with specific contributions from units dealing with fisheries, forestry, agriculture, environment and economics. This will set a much more coherent framework to inform national policy and prepare national investment programmes for responsible agricultural water development.
FAO Committee on Agriculture
Use Efficiency and Agricultural Productivity, January 2007