A physically-based model of long-term food demand

Abstract

Reducing hunger while staying within planetary boundaries of pollution, land use and fresh water use is one of the most urgent sustainable development goals. It is imperative to understand future food demand, the agricultural system, and the interactions with other natural and human systems. Studying such interactions in the long-term future is often done with Integrated Assessment Modelling. In this paper we develop a new food demand model to make projections several decades ahead, having 46 detailed food categories and population segmented by income and urban vs rural. The core of our model is a set of relationships between income and dietary patterns, with differences between regions and income inequalities within a region. Hereby we take a different, more long-term-oriented approach than elasticity-based macroeconomic models (Computable General Equilibrium (CGE) and Partial Equilibrium (PE) models). The physical and detailed nature of our model allows for fine-grained scenario exploration. We first apply the model to the newly developed Shared Socioeconomic Pathways (SSP) scenarios, and then to additional sustainable development scenarios of food waste reduction and dietary change. We conclude that total demand for crops and grass could increase roughly 35-165% between 2010 and 2100, that this future demand growth can be tempered more effectively by replacing animal products than by reducing food waste, and that income-based consumption inequality persists and is a contributing factor to our estimate that 270 million people could still be undernourished in 2050.

How food secure are the green, rocky and middle roads: food security effects in different world development paths

“…These price feedbacks are absent in exogenous food demand models (e.g. Bodirsky et al 2015, Pradhan et al 2016, Bijl et al 2017, and arise from price changes due to increase total demand (resulting from population growth or bioenergy use), and changes in the supply side. Food waste and preference changes are exogenous scenario-specific assumptions.…”

The global economic costs of substituting dietary protein from fish with meat, grains and legumes, and dairy

“…Bijl et al. () estimate an increase in crop demand of 70% relative to 2010 under a BAU scenario, mainly composed of higher demand for feed crops required to increase caloric intake from animal products. Hubert, Rosegrant, Van Boekel, and Ortiz () estimate increases of 56% for cereals, 41% of which to be utilized as feed, in the 2000–2050 period, and Valin et al.…”

“…Tilman et al (2011) conclude that global crop production, including feed for livestock and aquaculture, needs to increase by 100-110% (relative to 2005) to meet demand in 2050; Fischer, Byerlee, and Edmeades (2014) estimate crop demand in 2050 at 60% higher than in 2010; Springer and Duchin (2014) estimate increases by 2050 for crops (up to 51%), rainfed cereals (up to 96%), irrigated cereals (up to 136%), and livestock (up to 130%), all relative to 2000, based on alternative assumptions regarding changes in diets and agricultural technologies. Bijl et al (2017) estimate an increase in crop demand of 70% relative to 2010 under a BAU scenario, mainly composed of higher demand for feed crops required to increase caloric intake from animal products. Hubert, Rosegrant, Van Boekel, and Ortiz (2010) estimate increases of 56% for cereals, 41% of which to be utilized as feed, in the 2000-2050 period, and Valin et al (2014) estimate an increase of 59-98% for food demand, which turns out to be more sensitive to socioeconomic assumptions than to climatic variance.…”

“…A 50% reduction in food loss and waste can provide substantial reductions in resource use by 2050 (14% less cropland and 9% less pastureland; and 15% less water use and 23% less greenhouse gas emissions) and is regarded as a "sine qua non" condition for satisfying future food demand (Bajželj et al, 2014). While the potential of waste reduction in promoting food security by 2050 is significant, it may have a weaker impact than diet change: One study estimates that a 100% reduction in overall waste reduces food demand in 2050 by 10% relative to a BAU scenario, whereas global convergence to a low-meat diet reduces it by 41% (Bijl et al, 2017), a result that is consistent with Valin et al (2014), which highlights the increasing importance of diet choices in determining the adequacy of the future food supply.…”

A framework for modelling the complexities of food and water security under globalisation

“…The demand for each food commodity in a city and its hinterland is equal to (per capita demand taken from IAM × population), with population based on spatially explicit grid-scale population esti- mates (Bijl et al, 2017;Brinkhoff, 2016;Klein Goldewijk et al, 2011;UN Population Division, 2015). Cities and their hinterlands are either in surplus or deficit for a crop type based on (local production -local demand) .…”