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. 2017 May:153:190-200.
doi: 10.1016/j.agsy.2017.01.014.

Losses, inefficiencies and waste in the global food system

Peter Alexander  1   2 , Calum Brown  1 , Almut Arneth  3 , John Finnigan  4 , Dominic Moran  2   5 , Mark D A Rounsevell  1   3
Affiliations

Losses, inefficiencies and waste in the global food system

Peter Alexander et al. Agric Syst. 2017 May.

Abstract

Losses at every stage in the food system influence the extent to which nutritional requirements of a growing global population can be sustainably met. Inefficiencies and losses in agricultural production and consumer behaviour all play a role. This paper aims to understand better the magnitude of different losses and to provide insights into how these influence overall food system efficiency. We take a systems view from primary production of agricultural biomass through to human food requirements and consumption. Quantities and losses over ten stages are calculated and compared in terms of dry mass, wet mass, protein and energy. The comparison reveals significant differences between these measurements, and the potential for wet mass figures used in previous studies to be misleading. The results suggest that due to cumulative losses, the proportion of global agricultural dry biomass consumed as food is just 6% (9.0% for energy and 7.6% for protein), and 24.8% of harvest biomass (31.9% for energy and 27.8% for protein). The highest rates of loss are associated with livestock production, although the largest absolute losses of biomass occur prior to harvest. Losses of harvested crops were also found to be substantial, with 44.0% of crop dry matter (36.9% of energy and 50.1% of protein) lost prior to human consumption. If human over-consumption, defined as food consumption in excess of nutritional requirements, is included as an additional inefficiency, 48.4% of harvested crops were found to be lost (53.2% of energy and 42.3% of protein). Over-eating was found to be at least as large a contributor to food system losses as consumer food waste. The findings suggest that influencing consumer behaviour, e.g. to eat less animal products, or to reduce per capita consumption closer to nutrient requirements, offer substantial potential to improve food security for the rising global population in a sustainable manner.

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Figures

Image 2
Graphical abstract
Fig. 1
Fig. 1
Food system stages associated losses, and summary of approaches used to estimate each quantity.
Fig. 2
Fig. 2
Main flows in the global food system in 2011 from plant growth to human consumption, in: a) dry matter, b) energy, c) protein mass, and d) wet mass. Arrows denote the transfer from one process to another, and their width is proportional to the amount of mass or energy per year. Two flows are shown from harvested crops to livestock production, one for primary food crops (light blue) another for forage crops (yellow). The aggregate size of the cropland and grassland net primary production (NPP) flows are displayed as equivalent sizes across the four panels. The loss and waste flows include a substantial proportion of unharvested biomass and manure that will break down in the soil, providing nutrients for subsequent production.
Fig. 3.
Fig. 3
Embodied harvested crops (without forage crops) through stages in food system in dry matter terms.
Fig. 4
Fig. 4
Losses of harvested crops (excluding grassland and forage crop inputs to livestock production) by stage in the food system, using embodied loss rates.
See this image and copyright information in PMC

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