IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

5.3.2 Balancing future global supply and demand in agriculture, forestry and fisheries Agriculture

Slower population growth and an increasing proportion of better-fed people who require fewer additional calories are projected to lead to deceleration of global food demand. This slow-down in demand takes the present shift in global food consumption patterns from crop-based to livestock-based diets into account (Schmidhuber and Shetty, 2005). In parallel with the slow-down in demand, FAO (FAO, 2005a) expects growth in world agricultural production to decline from 2.2%/yr during the past 30 years to 1.6%/yr in 2000 to 2015, 1.3%/yr in 2015 to 2030 and 0.8%/yr in 2030 to 2050. This still implies a 55% increase in global crop production by 2030 and an 80% increase to 2050 (compared with 1999 to 2001). To facilitate this growth in output, another 185 million ha of rain-fed crop land (+19%) and another 60 million ha of irrigated land (+30%) will have to be brought into production. Essentially, the entire agricultural land expansion will take place in developing countries with most of it occurring in sub-Saharan Africa and Latin America, which could result in direct trade-offs with ecosystem services (Cassman et al., 2003). In addition to expanded land use, yields are expected to rise. Cereal yields in developing countries are projected to increase from 2.7 tonnes/ha currently to 3.8 tonnes/ha in 2050 (FAO, 2005a).

These improvements in the global supply-demand balance will be accompanied by a decline in the number of undernourished people from more than 800 million at present to about 300 million, or 4% of the population in developing countries, by 2050 (see Table 5.6) (FAO, 2005a). Notwithstanding these overall improvements, important food-security problems remain to be addressed at the local and national levels. Areas in sub-Saharan Africa, Asia and Latin America, with high rates of population growth and natural resource degradation, are likely to continue to have high rates of poverty and food insecurity (Alexandratos, 2005). Cassman et al. (2003) emphasise that climate change will add to the dual challenge of meeting food (cereal) demand while at the same time protecting natural resources and improving environmental quality in these regions.