Global population will continue to expand at a rate of 1.1 percent until 2015 and more slowly thereafter. Today's population of 6 000 million will reach 8 100 million by 2030, an increase of about 33 percent. As a result, demand for food will increase over this period but at a slowing rate.
The nature of the demand will also change as incomes rise and urbanization continues. The urban population is expected to increase from 43 percent of the world population in 1990 to 61 percent by 2030. As incomes rise, there will be a shift first from maize and coarse grains to rice, and then from rice to wheat. At the same time, there will be a shift in preference from cereals to meat and fish, with increasing demand for maize and other coarse grains as animal feed.
The growing population and changes in food preferences will result in a strong demand for additional food production, though the types of cereals demanded for food and feed, and the mix of cereals and animal products in the diet, will change. Predictions suggest that over the next 30 years overall crop production will thus increase considerably more than that required simply by population growth. Although net food imports into the developing countries are expected to increase, most of the increasing demand in those countries will be met by increased local production.
Increases in demand can be met in three ways:
Over the past 30 years or so, most of the increase - more than three-quarters - came from increases in yield, mainly as a result of the Green Revolution. This is also expected to be the case in developing countries over the next 30 years, with 69 percent of the production increase being covered by yield increase, 12 percent by increases in cropping intensity and the rest from increase in the area of cultivated land.
Much of the increase in crop production will come from irrigated land, three-quarters of which is in developing countries. Currently, some 20 percent of agricultural land in the developing countries is irrigated and it provides about 40 percent of crop production in these countries. Over the past 30 years, the irrigated area expanded at about 2 percent a year, giving a total increase of some 100 million hectares during 1962-98. The irrigated area in developing countries in 1998 was nearly double what it was in 1962.
There are many reasons why such rapid expansion will not continue, and most analysts expect the irrigation area to grow much more slowly in the future. FAO expects that irrigated areas in 93 developing countries could grow by 0.6 percent a year between 1998 and 2030. Such a rate of growth would lead to only a 23 percent increase in irrigated area over the period. However, when coupled with increased cropping intensity, the effective harvested irrigated area is expected to increase by much more: from 241 to 323 million hectares, a 34 percent increase.
Will there be enough freshwater to satisfy the growing needs of agriculture and other water uses? Agriculture already accounts for about 70 percent of the freshwater withdrawals in the world and is seen as the main factor behind increasing global freshwater scarcity.
An FAO analysis of 93 developing countries reaches comparatively encouraging conclusions on this question. During the period 1998-2030, irrigation water withdrawal in these countries is expected to grow by a total of only about 14 percent, from the current 2 128 km3/year to 2 420 km3/year in 2030. This increase is low compared to the increase projected in the harvested irrigated area. Most of this difference is explained by an expected improvement in irrigation efficiency, leading to a reduction in the withdrawals needed for irrigation water per irrigated hectare. Another part of this reduction will be due to a change in cropping pattern for some countries, such as China, where a substantial shift from rice to wheat production is expected: irrigation water requirements for rice are usually twice those of wheat.
Irrigation water withdrawal was estimated to account in 1998 for only 8 percent of total water resources for the 93 countries (see table on page 11). There are, however, wide variations between regions, with the Near East/North Africa region using 53 percent of its water resources in irrigation while Latin America barely uses 1 percent of its resources. At the country level, variations are even higher (see map on page 3). Of the 93 countries, 10 already used more than 40 percent of their water resources in 1998 for irrigation, a situation which can be considered critical. An additional eight countries used more than 20 percent of their water resources, a threshold which can be considered to indicate impending water scarcity.
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Increases in withdrawals for agriculture 1998-2030, percent 
Increases in water withdrawal for agriculture over the period 1998-2030 will be high (more than 100 percent) in 6 countries, and fairly high (50-100 percent) in 27 others. Increases will be less than 20 percent in 41 countries. |
The situation should not change drastically over the period of the study, with only two additional countries crossing the 20 percent threshold. Since additional water withdrawals will be needed for the non-agricultural sectors, the global picture in 2030 would not be very different from that in 1998, when agriculture used 85 percent of water withdrawals in developing countries. The key, of course, is how to increase irrigation efficiency (see pages 16-19).
For several countries. however, relatively low national figures may give a biased impression of the level of water stress: China, for instance, is facing severe water shortage in the north but the south still benefits from abundant resources. Even in 1998, two countries, the Libyan Arab Jamahiriya and Saudi Arabia, withdrew more water for irrigation than their annual renewable resources; groundwater mining also occurs in many other countries. Irrigation consumed a relatively small fraction of renewable water resources for the 93 developing countries in 1998. With a relatively small increase in irrigation water withdrawal expected by 2030, no major water crisis should affect irrigated food production at global level. This finding, however, should not lead to complacency since severe water shortages are already being experienced at local levels, particularly in the countries of the Near East and North Africa.
Irrigation efficiency and withdrawals for irrigation as a percentage of renewable water resources, 1998 and 2030 | ||||||
sub-Saharan Africa |
Latin America |
Near East/ North Africa |
South Asia |
East Asia |
93 developing countries | |
Irrigation efficiency (%) | ||||||
1998 |
33 |
25 |
40 |
44 |
33 |
38 |
2030 |
37 |
25 |
53 |
49 |
34 |
42 |
Irrigation water withdrawals as a percentage of renewable water resources | ||||||
1998 |
2 |
1 |
53 |
36 |
8 |
8 |
2030 |
3 |
2 |
58 |
41 |
8 |
9 |