The impact of refrigeration on food losses and associated greenhouse gas emissions throughout the supply chain
This study uses a food loss estimation tool to quantify changes in food loss and associated greenhouse gas (GHG) emissions that may occur with the introduction or quality improvements of cold chain technology, as well as the length of a food supply chain (FSC). The analyzed scenarios illustrate the differences between more localized, less industrialized FSCs and globalized, more technologically-advanced FSCs. By modeling food losses at each stage of the supply chain, this study highlights where the cold chain can be strategically deployed and optimized to direct food system investments to reduce food losses and emissions.1.1. Refrigerated supply chain ('cold chain')Ideally, the cold chain provides an unbroken, controlled atmospheric environment to ensure the quality and safety of perishable products throughout all stages of a supply chain (Ma and Guan 2009, Aung and Chang 2014). The 'cold chain' refers to both temperature and humidity control, incorporating both physical technology and logistical management (Garnett 2007, Heard and Miller 2019). In the context of this paper, the term 'refrigeration' is used to represent the suite of cold chain interventions, which vary according to the requirements of different food types and can include cool storage, frozen storage, and humidity control with or without temperature control. With regard to food supply, the cold chain extends from farms and processing plants to retail (grocery) and foodservice operations (Garnett 2011, Kitinoja 2013). The cold chain provides many safety, nutritional, and health benefits. By extending the shelf life of food, the cold chain can improve and expand access to perishable foods and reduce spoilage and foodborne illness (Heard and Miller 2019). The cold chain is also necessary for effective vaccine and antibiotic delivery (Heard and Miller 2019). A continuous, unbroken cold chain is necessary to maximize the benefits of safety and reduce product losses; however, in many non-industrialized economies 1 , cold chain elements may have inconsistent quality, continuity or lack cold chain elements entirely (Ishangulyyev et al 2019).This study analyzes the effects of moving from the current state of inconsistent and variable quality cold chains throughout the world to an optimized system.1.2. Broad impacts of food loss and wasteThe United Nations' Sustainable Development Goals 2 and 12 mention achieving food security and improved nutrition, and addressing food losses along supply chains, respectively (UN 2015). Delivering on these goals is critical from humanitarian, environmental, and financial perspectives and the cold chain can have a role in achieving these objectives. While estimates vary, approximately one-third of food produced globally, 1.3 Gt, is wasted, equating to approximately 4.4 GtCO2e annually (Gustavsson et al 2011, FAO 2015). Concomitantly, it is estimated that 720–811 million people suffer from hunger (FAO et al 2020). The financial cost of food loss and waste alone (excluding fish & seafood) is $750 billion annually; this does not take into account the financial costs of disposal, logistics, environmental damage, nor the human potential lost if the food were effectively distributed (FAO 2013).Understanding where losses occur in the FSC is critical to addressing systemic inefficiencies that contribute to both hunger and climate change. While food loss and waste are global issues, the patterns of food loss and waste differ. In higher income, more industrialized regions, a greater proportion of food is wasted (>40%) at the consumption phase of the FSC. In lower income regions, more than 40% of food losses occur in the early stages (post-harvest and processing) of the FSC, often due to poor logistics and lack of climate control via the cold chain (Gustavsson et al 2011). While fully-developed and under-developed cold chains are often represented as binary, mutually distinct states, the reality is that development of a cold chain is a stepwise, context-specific process. This model examines differences in refrigeration qualities (none, poor, average, good) for each stage of a FSC, as well as a comparison of long multi-stage FSCs with very short farm-to-consumer FSCs. This model can provide critical insights into the region- and food type-specific tradeoffs of cold chain implementation, thereby informing optimal FSC development.1.3. Prior FSC-cold chain researchResearch on food systems and the cold chain has been growing over the past couple decades but remains fragmented and limited in terms of direct applicability to FSC stakeholders. Most studies fall into one of two types: historically based (meta) analysis and theoretical projection models. The former uses historical data to assess trends and rationalize those trends on regional and global scales. Gustavsson et al (2011) presents a critical meta-analysis of global FSCs, examining the stage-specific losses regionally and providing insights into the causes behind regional food losses and potential solutions. Porter et al (2016) built upon Gustavsson's research to publish region- and food-specific emission factors for various food products and food types. The latter approach has largely utilized storage conditions, namely temperature and time, to model food degradation and loss. James and James (2010) provide one of the earlier and more robust analyses on the relationship between food loss and climate change. Several other studies have focused on cold chain development in China, utilizing conditions-based frameworks to illustrate how various environmental factors can impact shelf life and food loss (Dong and Miller 2021, Hu et al 2019, Wu et al 2022).More recent academic and industry studies have used historical data and development trends to model and understand how refrigeration may manifest in non-industrialized regions. Heard and Miller (2019) model the development of a Sub-Saharan African cold chain, including food losses, dietary changes, and the emissions associated with those factors. The Global Food Cold Chain Council (2015) modeled cold chain development by comparing cold chain penetration and food loss and waste data in non-industrialized regions with that of industrialized regions.Unlike previous research, this study focuses on potential improvements that can be realized by cold chain upgrade and optimization at specific stages within the FSC, focusing specifically on partial or suboptimally functioning refrigeration. Additionally, this study explicitly compares the losses and associated emissions of shorter, less refrigerated FSCs with extended, more refrigerated FSCs.
Ideally, the cold chain provides an unbroken, controlled atmospheric environment to ensure the quality and safety of perishable products throughout all stages of a supply chain (Ma and Guan 2009, Aung and Chang 2014). The 'cold chain' refers to both temperature and humidity control, incorporating both physical technology and logistical management (Garnett 2007, Heard and Miller 2019). In the context of this paper, the term 'refrigeration' is used to represent the suite of cold chain interventions, which vary according to the requirements of different food types and can include cool storage, frozen storage, and humidity control with or without temperature control. With regard to food supply, the cold chain extends from farms and processing plants to retail (grocery) and foodservice operations (Garnett 2011, Kitinoja 2013). The cold chain provides many safety, nutritional, and health benefits. By extending the shelf life of food, the cold chain can improve and expand access to perishable foods and reduce spoilage and foodborne illness (Heard and Miller 2019). The cold chain is also necessary for effective vaccine and antibiotic delivery (Heard and Miller 2019). A continuous, unbroken cold chain is necessary to maximize the benefits of safety and reduce product losses; however, in many non-industrialized economies 1 , cold chain elements may have inconsistent quality, continuity or lack cold chain elements entirely (Ishangulyyev et al 2019).This study analyzes the effects of moving from the current state of inconsistent and variable quality cold chains throughout the world to an optimized system.
