Cropping intensity is projected to increase from 79 to 85 percent, and increases in average crop yields will account for two-thirds of the projected growth in crop production. The increase in arable land devoted to crop production excludes additional land needed for human settlements, industry and infrastructure, and for shifting agriculture and grazing which escape official statistics. However, most land with some crop production potential faces production constraints - of slope, soil type or climate. It may be under forest cover or be providing another environmental service. Its use will therefore involve a trade-off.
Water scarcity is a constant constraint for countries with arid and semi-arid climates.
Of major concern is the lack of storage facilities and a continuing decrease in the rate of expansion of irrigated land in developing countries while population growth rates are about 1.8 percent per year. These will require consideration of the opportunity costs of water in different uses and pricing systems that take account of the economic costs of water supply, rather than the numerous forms of water subsidy that currently exist and which encourage profligate use, even in dry countries. Part of the problem lies in the measures adopted by industrialized countries to subsidize and protect agriculture. At the same time, the policies of some developing countries do not encourage saving, investment, employment and income generation in support of sustainable rural development. The agricultural policies of industrialized nations tend to stimulate surplus production.