Demand for food is driven by population (which defines an absolute minimum threshold for collective sustenance) and GDP per capita, a measure of wealth which correlates with individual consumption. Demand functions for food from vegetal and animal sources (diagrammed at right) are calculated independently in the model.
The results of the model in the BAU scenario are plotted below. The lighter brown and green lines represent endogenously-calculated demand (per capita & daily) for animal and vegetal calories, respectively. These functions are calibrated to FAOSTAT data on global food supply (shown in darker colors), such that demand outstrips supply only marginally, leading gradually to expanded production.
On a per capita basis, demand for vegetal and animal calories are projected to grow 16% and 39%, respectively, between 2010 and 2100. Over the same period, median population projections grow 56%. Together, these factors result in 117% (82%) growth in global animal (vegetal) food production, as shown below.
In the plot above, the light green and brown shaded regions propagate the full range of population estimates to illustrate the consequences of this range on food production. In the case of vegetal food, this region is asymmetric (circled) due to competition for agricultural land as well as the indirect-yet-consequential downward pressure of increased population on agricultural yields.
Agricultural Yield represents a conversion factor which translates Vegetal Food Demand and Vegetal Food Production into Food Crop Land Needed and Food Crop Land, respectively. Discrepancies which may occur between land-needed and land-under-tillage drive the transformation of land either into or out of service as agricultural land. A separate yield factor is calculated for Animal Food Land and Animal Food Land Needed.