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An Introduction to Life Cycle Assessments

Everything we use in our everyday life has a story. We define the history of food that we eat as “from cradle to grave” or “from field to fork”.

In other words, we need to analyze which inputs the production, warehousing and distribution of a product has received in terms of energy to estimate the full extent of the impact of the food on the environment.

In the past, little focus was put on fully balancing the inputs of the food value chain, and it is often looked at as a “linear economy”. Currently much emphasis is given to the creation of circular value chains, where products are reutilized in a cycle, before their unused components are finally discarded.

Circular food value chains are at the basis of a more sustainable diet and have a lower carbon footprint than those value chains that are “linear” in nature. In these calculations, we need also to take into consideration the side products obtained during production of food ingredients and the waste by-products during processing, or the packaging material we discard at the end of life of the product. It becomes clear then, that anything that reduces waste will decrease the overall carbon footprint of our food. In a circular economy, most inputs move along the value chain, and there is no waste, but a continuous cycle of re-utilization. The concept in a circular economy is different, no longer from “cradle to grave” but from “cradle to cradle”. This means avoiding landfill, incineration and other ways to distribute waste in the environment. But, how can we truly measure this impact?

Life Cycle Assessment

To evaluate the environmental effects associated with a product or an industrial activity, we need to consider all inputs and outputs, from the initial gathering of the raw material to the point at which all residuals are returned to Earth, using a common methodology. This methodology needs to be agreed upon, standardized and validated, so that the data can be compared. This is called a Life Cycle Assessment (LCA).

The code of practice for LCA is currently a general methodology, which includes four steps:

1) Scoping

2) Collecting data on all direct and indirect material and energy inputs and waste emissions

3) Assessing the impact

4) Generating an improvement assessment.

Recently, the international organization for standardization (ISO) has developed international standards for LCAs. This underlines the extreme importance of this new discipline to create baselines and to measure how our diets contribute to environmental erosion and how we can improve creating measurable performance indicators.

LCA studies are now widespread. However, there are still some deficiencies, as the data needed to calculate greenhouse gas emissions are often lacking. A number of studies focus on system boundaries up to the farm gate or retail stage, as the production phase seems to have the largest environmental impact. However, the consumer stage should also be included in food related LCAs, to fully estimate how food consumption patterns affect environmental impacts in various countries.

Food Waste

Every year, a large portion of what is considered food fit for human consumption is lost or wasted across the value chain. Food waste and packaging waste also need to be considered in a full estimate of our diet environmental impact.

The food waste problem is complex, causes negative economic, environmental and social effects, and thus needs to be addressed in LCA as well. Food waste refers to losses at any stage of the value chain, in production, post-harvest, processing, storage, distribution, and household or food service, which are not recovered for human consumption.

In developed countries and urban environments, the biggest contributors to food waste are at the end of the supply chain, at distribution and consumption, while in lower income countries or in weather challenged areas, the losses are in the production and post-harvest stages.

Seasonality, ambient temperature and transportation can also have huge impacts in calculating the carbon footprint and greenhouse gas emissions of what ends up to be a unit of food. Furthermore, more refined foods and ingredients also result in the creation of waste by-products, co-products of less value, and processing waste that also needs to be included in the boundaries of the LCA estimations.

In developed countries, household waste accounts for more than 50 % of the food waste. In recent studies, this food waste was estimated to vary between 60 and 200 kg per year in a household. From the consumer point of view, food waste may be seen as just a waste of money, affecting the household economics. However, its negative impact on the environment is substantial, with large emissions of greenhouse gases, wasteful use of input resources, and a cumulative effect as it covers the input of the entire value chain.

Recently, the COVID-19 pandemic has changed our shopping habits, and consumers have become aware of supply chains by looking at empty grocery store shelves. The logistics needed to be re-worked, with less need for specific outlets such as schools, restaurants and hospitality businesses. This has also affected the generation of food waste, with impacts on farmers of perishable produce, who were not able to harvest or packaging of the products in the appropriate size or format for retail.

The consumer behavior will be the key to improving the environmental footprint of our food. For example, the waste in primary production for fruit and vegetable may be decreased by loosening some of the strict quality standards brought by consumer and retailers. However, lower class products will yield lower profits, and therefore lower financial viability, even at harvest. New practices such as purchasing smaller sizes, or better packaging, designed to decrease household waste and increase shelf life may be needed to eliminate the fraction of waste that is avoidable and avoid discarding food that could have been eaten if handled correctly or eaten by the “use by date”.

In conclusion, in the quantitative evaluation of the environmental impact of our food, a full account of all the inputs and the inclusion of all stages of the circular value chain is of great importance, to be able to evaluate any unintended consequences, which result from shifts in diets, production practices or consumer behaviors. It will also be very important to communicate changes and improvements to consumers, by using measurable indicators, so that responsible choices can be made.

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This article is from the free online course:

Introduction to Food Science

EIT Food