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Waste a Lot, Warm a Lot – Reducing Food Waste is Part of Climate-Friendly Eating

Posted by Nicole Bell | May 27, 2021
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This article is part of a series, Climate Friendly Fruit & Veggies, highlighting work from the Fruit & Vegetable Supply Chains: Climate Adaptation & Mitigation Opportunities project, a collaborative research study co-led by investigators at the University of Florida and the Agriculture & Food Systems Institute. Other collaborating institutions include researchers at the University of Arkansas, University of Illinois, the International Food Policy Research Institute, the World Agricultural Economic and Environmental Services, and Washington State University. This project seeks to identify and test climate adaptation and mitigation strategies in fruit and vegetable supply chains.

While many scientists, producers, and consumers recognize the importance of quantifying the carbon footprint of agriculture, most efforts focus on on-farm activities. The journey food takes before it lands on a consumer’s plate is complex and requires looking beyond the farm gates: as it turns out, the consumer’s plate plays an important role in the overall environmental footprint of a given product. In a recent article, we explored insights related to preparation of French fries from a study led by Ranjan Parajuli on the relative impact of different parts of the supply chain (on-farm, processor, retail, and consumer) for fresh and processed potato and tomato products. Here, we examine another aspect of supply chain impacts of potato and tomato products: food waste. The results indicate that waste contributes significantly to greenhouse gas (GHG) emissions.

Although waste occurs at each stage along the supply chain, there is great uncertainty about fruit and vegetable losses during production and harvesting (combined) in North America, which have been estimated at both 20% (Elik et al. 2019) and 30% (Minor et al. 2020). Because of this uncertainty, Parajuli’s study focused on loss occurring after the product leaves the farm. Food waste refers to edible food that remains unconsumed for a multitude of reasons, including mold, pests, natural shrinkage or moisture loss, produce with visual defects, as well as more commonly understood food waste methods like plate waste. The “cradle-to-grave” life cycle assessment, or LCA, used in this study allows the authors to determine which stages in the supply chains for potato and tomato can provide the greatest opportunity for environmental mitigation. The study first evaluated where along each supply chain the waste occurs, and then determined the greenhouse gas emissions such waste would produce. The authors compared two vegetables, potatoes and tomatoes, and two supply chains for each: fresh market or processed. Here we focus on the results for fresh market potatoes.

Environmental impact from food waste is more than just significant. The GHG emissions due to waste for fresh market potatoes were estimated to be 57% of total emissions along the supply chain, representing 0.97 kg CO2-eq for each kg of potato consumed. For the retail and consumer stages of the supply chain, waste contributes an estimated 33% of these GHG emissions. Parajuli’s results indicate that for every 1 kg of potatoes eaten by the consumer, 1.49 kg leaves the farm (Figure 1). Losses occur at different points along the supply chain, but 55% of the post-farmgate losses occur at the consumer stage.

Graph showing food mass lost from field (1.49kg) to finish food (1.0kg). Consumer waste represents 55% of post-farm-gate waste.
Figure 1. Food loss depicted along the supply chain for fresh market potatoes. Data from Parajuli et al. (2021). Figure by L. Tarar.

A Roadmap to Reduce U.S. Food Waste (ReFed 2016) argued that a 20% reduction of food waste is possible within the next decade. The Environmental Protection Agency and United States Department of Agriculture jointly declared their goal to reduce food waste in the U.S. by half by 2030 in order to align with the UN Sustainable Development Goals (EPA). Parajuli’s study results suggest that the biggest opportunities to reduce food waste occur at the on-farm and consumer stages of the supply chain. If losses occurring at the consumer stage of the supply chain were reduced by half, the GHG emissions for fresh market potatoes would be reduced by 11.8%, which would be equivalent to taking 168,534 cars off the road. What mitigation methods could make this reduction possible? There are nearly endless options mentioned in the Parajuli study, including standardizing date labels, secondary reselling, cold chain management, food donation, consumer education. It is not yet clear which methods appeal the most to producers, processors, or other players in the supply chain, but the good news is clear: there are options.

Not only does reducing food waste make sense from an economic perspective, it can also benefit the environment. When food waste is reduced, more consumed food can be produced with the same amount of land, and GHG emissions are reduced by keeping food waste out of landfills. As the demand for fresh fruits and vegetables increases with more people on the planet and greater per capita fresh produce consumption, it will be important to identify effective strategies that reduce waste throughout supply chains. In particular, it will be important to pay attention to reducing on-farm and consumer waste in ways that do not lead to increases in GHG emissions in other parts of the supply chain.  The old adage, waste not, want not, may be even more relevant than ever in a changing climate.

This work was supported by USDA-NIFA Award No. 2017-68002-26789.

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