Changes in both human and physical systems will impact global food access and availability. These impacts will occur unevenly, both across and within countries. Understanding the implications of changes in the climate system, trade patterns, and economic and demographic characteristics on global and local food systems is key to evaluating human well-being.
We use a global, fully integrated, Multi-sector Dynamics, human-Earth system model, the Global Change Analysis Model (GCAM 7) to explore the distributional impacts of climate change on crop yields, increasing or decreasing global trade, and alternative socioeconomic pathways. In this version of GCAM, we model consumer food demand using multiple groups within each region, represented by ten income deciles. This development allows us to explore the ways in which changes in these systems may differentially impact different groups, particularly lower-income consumers who may be most vulnerable to these changes.
We estimate eight measures of food access and availability: Dietary Energy Supply (DES), share of DES from staple foods, DES adequacy, protein supply, protein supply of animal origin, fat supply, cereal import dependency ratio, and share of food expenditures of the poor. Our results show large differences in these outcomes both across and within regions.
Increasing incomes throughout the century will result in improved measures of food access and availability in most regions. However, these improvements are unevenly distributed. For instance, DES adequacy (caloric sufficiency relative to the Minimum Daily Energy Requirement (MDER)) in India decreases for the lowest income decile between 2015 and 2050. While it improves by 2100, particularly for the lowest income decile, 30% of the population still does not have access to sufficient calories. In 2015, 80% of the population is below the MDER in Eastern Africa. There are large projected improvements for this region, however, with all income groups meeting the MDER in 2100. Similar patterns are seen for the share of staple calories (where a higher share indicates poorer nutritional outcomes) and total protein supply