than for cereals alone. Across the assessments, the area in crop production increases from 1.5 billion ha (or 11% of the earth's land surface) to 1.60 to 1.77 billion ha. As in­dicated by FAO, this expansion is within the scope of total land available for crop production. The fact that the assess­ments considered here agree on a rather flexible continuous response of the agriculture system to demand increases is in­teresting, as more skeptical views have also been expressed. An important implication, however, is further loss of the area available to unmanaged ecosystems
.
 Global livestock production. Livestock production systems differ greatly across the world. Confined livestock produc­tion systems in industrialized countries are the source of most of the world's poultry and pig meat production, and hence of global meat supplies (FAO, 2002b). Such large-scale livestock systems are also being established in developing countries, particularly in Asia, to meet increasing demand for meat and dairy products. Livestock production also oc­curs in mixed crop-livestock farming systems and extensive grazing systems. Mixed crop-livestock systems, where crops and animals are integrated on the same farm, represent the backbone of small-scale agriculture throughout the devel­oping world. Globally, mixed systems provide 50% of the world's meat and over 90% of its milk, and extensive pas­ture and grazing systems provide about 20-30% of beef and mutton production. To date, extensive grazing systems in developing countries have typically increased production by herd expansion rather than by substantial increases in productivity, but the scope for further increases in herd numbers in these systems is limited. The share of extensive grazing systems is declining relative to other systems, due both to intensification and to declining areas of rangeland. Considering all food production systems together, livestock production is the world's largest user of land (about a quar­ter of the world's land), either directly for grazing, or indi­rectly through consumption of feed and fodder.
     As incomes increase, demand for animal products in­creases as well. This trend, which has been empirically established in all regions, is assumed to continue in the sce­narios of the three assessments considered here. As a result, meat demand is projected to increase at a greater rate than the global population. Changing dietary preferences also contribute to this increased demand in the scenarios. Inter­estingly, future meat production varies considerably more than future cereal production among the scenarios (Figures 4-31, 4-32, 4-33). Assessments indicate similar growth rates for other animal products such as milk.      The increases in meat production will occur through a number of means, including changes that lead to intensi­fied production systems, such as expansion of land use for livestock, and more efficient conversion of feed into animal products (Figure 4-34). Both the MA and FAO assessments indicate that most of the increases in world livestock pro­duction will occur in developing countries; second, while scenarios differ in their projections of future pasture area, compared with crop land area most scenarios expect very little increase in pasture land. For grazing systems, this means that some intensification is likely to occur particu­larly in the humid-subhumid zones where this is feasible. Considerable intensification is likely in the mixed systems,

with further integration of crop and livestock enterprises in many places. Strong growth is implied for confined livestock production systems; in the FAO scenario at least 75% of the total growth is in confined systems, although there are likely to be strong regional differences (e.g., less growth of these systems in Africa). This is a continuation of historic trends. The major expansion in industrial systems has been in the production of pigs and poultry, as they have short reproductive cycles and are more efficient than ruminants in converting feed concentrates (cereals) into meat. Indus­trial enterprises now account for 74% of the world's to­tal poultry production, 40% of pig meat and 68% of eggs (FAO, 1996). At the same time, a trend to more confined systems for cattle has been observed, and a consequent rapid increase in demand for cereal- and soy-based animal feeds (these trends are included in the projections discussed in the previous subchapter) (see Delgado et al., 1999).      Finally, while there are good economic arguments for the concentration of large numbers of animals in confined systems, there can be significant impacts on surrounding ecosystems, something that is only recently started to be as­sessed in sufficient detail in agricultural assessments. The effects primarily involve N and P cycles. While some types of manure can be recycled onto local farmland, soils can quickly become saturated with both N and P since it is costly to transport manure.

Forestry. The FAO assessment pays considerable attention to forestry and the outlook for forestry, but mostly in a qualitative way. The MA also considers the future of forest­ry, but focuses more on the extent of natural forests than the development of forestry as a production system (although some data is available). Overall, both assessments agree on that the general trend over the last decades of a decreasing forest resource base and an increasing use of wood products will continue.      Important driving forces for forestry include demo­graphic, sociopolitical and economic changes, changes in extend of agricultural land, and environmental policy. Both population and economic growth affect forestry directly via an increase in demand for wood and indirectly via the impact on agricultural production. There is strong evidence that with rising incomes, demand for forest products increases, especially for paper and panel products. The increasing de­mand for wood products is also assumed in the scenarios of the FAO and MA (Figure 4-35). The demand for industrial roundwood is expected to increase by about 20-80%. The lowest projection results from the Technogarden scenario (assumes a high efficiency of forest utilization in order to protect forests) while the highest projection results from the Global Orchestration scenario (reflecting the very high eco­nomic growth rate).      The use of wood products as a source of energy (fuel-wood) is not expected to grow fast, and may even decline. The use of fuelwood is particularly important at lower in­comes; wealthier consumers prefer and can afford other forms of energy. As a result, fuelwood consumption is a function of population growth (increasing fuelwood de­mand) and increased income (decreasing demand), with the net results being a small decline and rise over the next 30 years. The impact of environmental policies on forestry may