Looking 30 years into the future, FAO estimates that feeding the world's population will require 60% more food. Most of that increase will have to come from intensified agriculture, supported by irrigation. But water is already scarce in many countries, and competition for water from industrial and domestic users continues to grow. So where will we find the water to grow the crops that feed the world?
FAO says the answer lies in improving agricultural productivity and water use efficiency. By using better seeds, boosting soil fertility and implementing other improved agricultural techniques, farmers produce higher yields and obtain the greatest gains from precious water supplies. And, through more efficient irrigation methods and enhanced water harvesting, water is put to its best advantage. Thanks to these advances, it is possible to generate the additional food needed with only 14% more water. At the same time, however, efforts will also needed to provide users with fair and equitable access to water, and to address environmental concerns - irrigated agriculture yields two to three times as much as rainfed lands, but can also cause salt build-up in soil and groundwater. And the overuse of water in one area can deprive people of access in another.
Agriculture: primary user of water. Agriculture is by far the largest user of water, claiming almost 70% of the total amount withdrawn globally. It takes a remarkable amount of water to produce crops - one to three cubic metres to yield just one kilogram of rice, for example. As population grows, water needs for agriculture can only increase. But supplies are already limited. An FAO study of 93 developing countries indicates that a number of water-scarce nations are already withdrawing water supplies faster than they can be renewed. Ten countries are in a "critical state", meaning that agriculture accounts for more than 40% of total withdrawals of renewable water resources. Another eight are "water stressed" - satisfying the needs of agriculture requires them to withdraw more than 20% of that total.
There is growing competition for water from municipalities and industry. Currently, industry claims about 20% of total water withdrawals, and municipal users another 10%. But of the amount they claim, only 10 to 20% is actually consumed. We will need to reuse a greater portion of the 80 to 90% that is wasted. And before it is reused or returned to rivers and aquifers, water must be treated to remove pollutants.
Tools to improve irrigated and rainfed production. Though developing countries depend on both irrigated and rainfed crops to feed their people, much of the increase in food production will need to come from irrigated land. FAO expects that irrigated areas in developing countries could expand by 20% by 2030. Coupled with increased cropping intensity, the effective harvested area will grow by about one third, from 250 million to 320 million hectares. Finding enough water to support that increase requires producing more crop per drop. The most common forms of irrigation - surface irrigation, in which water floods fields, and sprinkler irrigation, which mimics rainfall - can waste water. More efficient are localized methods such as drip irrigation, which put water only where it is needed.
Rainfed agriculture, which currently produces more food overall than irrigated agriculture, benefits from practices to maximize the collection of rainwater. Water harvesting - collecting water in structures ranging from small furrows to dams - allows the farmer to conserve rainwater and direct it to crops. Water harvesting can boost yield two to three times over conventional rainfed agriculture. Introducing improved varieties and better cropping patterns, and using minimum tillage methods which conserve water, further increase yields. An example of the spectacular results that can be achieved by making these improvements is found in the Keita Valley in Niger. Over four million people-hours of work, which included digging wells and building water-collecting structures such as weirs and bunds, transformed the valley from a barren desert to a garden for crops, livestock and trees.
Training farmers in water management is a priority for FAO. Together with development partners, such as the International Programme for Technology and Research in Irrigation and Drainage (IPTRID), FAO is helping member countries to set up technology research programmes, organizing workshops and training sessions and establishing networking activities such as electronic fora and newsletters so countries can exchange information about best practices. And to ensure that women and men benefit equally from policies and programmes on water, FAO's Socio-Economic and Gender Analysis (SEAGA) initiative holds workshops and produces training manuals based on three guiding principles: the different roles of men and women are key, disadvantaged people are a priority and successful training requires participation.
Policies today to ensure water tomorrow. Policies to guide agricultural water use are needed at the international, national and local levels. International agreements are especially useful when major sources of water cross more than one country. For example, with technical assistance from FAO, the 10 nations bordering the Nile River are implementing the Nile Basin Water Resources project as part of the Nile Basin Initiative, helping them to access and manage water equitably. The United Nations has developed a framework convention, now ratified by 10 states, to guide negotiations concerning the management of fresh water. It will come into force after ratification by 35 nations.
Local traditions of water management and access must also be considered to ensure they don't conflict with government policies. To back up new water policies, investment is required. National governments will need to establish the conditions to attract such investment. Innovative forms of credit will also be needed to help the poor take advantage of improved water management techniques.
Text by the FAO Multimedia Group (GII)
Published October 2002