01 Apr The life of your food: A discussion of LCAs
A low impact lifestyle has become desirable as the consequences of our excessive consumption are exposed. However, how do we assess the environmental impacts that our product choices have? Here, we discuss the use of life cycle analyses (LCAs) and the challenges and opportunities these pose in estimating the environmental impact of our food systems.
LCAs are an assessment method used to estimate the environmental impact of items over their lifetime. Such impacts can include water use, land use and greenhouse gas emissions (GHGs). When used correctly, they can be an effective comparative tool between similar items and highlight points in the value chain for improvement.
LCAs have a number of stages, and there are a range of types of LCA. Lifecycle inventories (LCIs) are first collected, which take account of all inputs and outputs within a system. This is followed by LCIAs (lifecycle impact assessment) where the impacts of LCIs are quantified and often differentiated into ecosystem impacts, human impacts and resource depletion. The commonly used term ‘footprint’ can represent a partial or full LCA, but only focuses on one aspect of the system. For example, a water footprint assesses the impact on water availability and quality across the entire life cycle of the product, but this would not include the impact on carbon emissions or land use.
LCAs are recognised as a useful impact assessment tool and as such have standardised methods set by ISO (International Organization for Standardisation). These guidelines have been interpreted differently throughout the literature, especially when applied to a system requiring the allocation of upstream products and inputs that serve in more than one system. For example, water used to irrigate rice paddies would form part of the water footprint of the rice. However, if the rice straw is also used as animal feed, how should the water footprint be allocated between the rice and animal production? Another issue with the methodology when applied to GHGs is that it typically only uses the GWP100 climate change metric, which can misinterpret short lived gas potentials e.g. methane. These limitations highlight the complexities of LCAs and the need for consistent methodology to improve the reliability of the assessment.
Using LCAs for the estimate of a product’s impact provides a landscape where the products can be compared. Although this can see misinterpretation, which will be discussed later, the complexities of this process can also offer up informative results for consumers and producers that may not seem obvious at first glance. This can be best used when comparing products that are similar in their final output (i.e. provide an equivalent user benefit), but may differ in their production chain e.g. competitor products, items produced in different regions and countries, or comparing similar products manufactured by the same company.
One product may have a variety of impact levels dependent on its origin, where it was purchased, right down to the practices of the individual farmer. Simple consumer choices may significantly decrease an individual’s impact. When choosing a discretionary food like chocolate, the choice of dark chocolate over milk or white chocolate significantly reduces the environmental impact. A difference in the nutritional composition of these products should be noted, although it is not a product we eat for its nutritional benefit. Furthermore, it has also been found using LCAs that a change to using 100% recyclables will result in minor reductions in an individual’s carbon footprint, and rather a focus on simply reducing consumption of packaging would see better results.
One of the most robust uses of LCAs is in the optimisation of company production lines. An internal LCA can pinpoint both the area with the most opportunity to reduce impact (e.g. manufacture, shipping, retail) or highlight one product having less impact than another, signifying its value for the company. Having numerical figures produced by LCAs can also provide tangible options for tracking improvements through regular analyses. For example, following its first LCA in 2009, Nespresso committed to reducing the carbon footprint of a cup of its coffee by 28% by 2020. Through these LCAs, Nespresso also investigated the impact between coffee systems to show the use of Nespresso was equal in carbon footprint with three other common coffee systems, while fully automated coffee systems had the highest carbon footprint. Not only does the direct product hold opportunity for more sustainable consumption choices; so too do the processes used to extract the coffee.
The benefits of the accurate use and awareness of LCAs go further than educating individuals or companies. As the literature on LCAs increases across a broader range of products, processes and end-of-life options, it allows consumers to make informed decisions in their quest for a truly low impact life. This also provides critical data to modelling platforms such as the DELTA Model®.
With the complexities of LCAs comes the opportunity for misleading comparisons. This can be through comparing two products that have little similarity in characteristics, comparing different parts of the value chain (cradle-to-farmgate versus cradle-to-grave), or only using one footprint to pull conclusions on an item’s entire impact. These have led to some misconceptions, especially when inappropriately exploited by commercial interests to promote one product over another. For example, plant-based milks being touted by some as better for the environment than dairy.
The environmental impact of bovine milk has shown significant variation between different countries, right down to differences inter-regionally. This variation allows the impact assessment outputs to be picked in favour of marketing claims by competitors. When used to compare bovine milk to plant-based alternatives, LCAs can create oversimplified and misinterpreted conclusions such as assuming nutritional equivalence between products, or using global average impacts not representative of the variation between production systems. More appropriate use of LCAs in milk comparisons would be to compare plant-based milks with one another, or compare different farming systems and practises between countries.
This scenario exemplifies the potential misuse of the tool, and highlights a gap in the literature that LCAs are yet to fill when applied to delivery of nutrition. A focus has been placed on whole products and macronutrients, where LCAs give footprints per kg of product or, less commonly, per kg of protein. Micronutrients are yet to be explored and would be an instrumental addition when considering the entire impact of food. This has become even more critical as deficiencies in specific nutrients when feeding the global population have been suggested by the DELTA Model®. This gap can be demonstrated in LCA comparisons of protein sources that claim protein powders are more efficient protein sources than cheeses, grains and beef when considering their environmental impacts. This study does not include the numerous micronutrients also received from the ‘less efficient’ protein sources.
Taking a holistic view, you could argue that given the interconnectivity of complex systems such as the food system, even seemingly unrelated factors can have indirect impacts on one another. LCAs can provide an excellent measurement tool when estimating the impact of products on individual environmental factors. However, the examples of misinterpretation and the opportunity for further research demonstrate how the application of LCAs can fall victim to tunnel vision when estimating a product’s true impact. This absence of a holistic view can produce results misleading for consumers. Narrow LCAs provide one piece of the puzzle and consideration should be made of the broader impacts the product has on our planet, our bank accounts, our health and our livelihoods.
Photo by Coffee with Joshua on Unsplash
