Happy 2023 everyone! I thought we could start the year with a light topic—research methods!
About 5 years ago, I met Basak Topcu at the Canadian Association for Food Studies conference. We (Renita and I) were presenting on the same panel as Basak, who presented research from life-cycle assessment. I immediately recognized the power of a method to measure and quantify the greenhouse gas emissions of foods, and ever since then, I’ve wanted to bring her knowledge and insight to other dietitians. A key part of building dietetic competence in climate-friendly food is to understand how we know what we know. So how do we measure the climate impact of foods, and what do we base our recomendations on? To bring life-cycle assessment to dietitians, I knew I wanted to talk to Basak.
I’ve lightly edited Basak’s responses below for length.
1. What is life-cycle assessment (LCA)?
It’s a systems-thinking method to quantify the impacts of a product throughout its entire supply chain, from extraction to disposal, considering all inputs, i.e. energy and materials, and outputs, i.e. greenhouse gas emissions and waste.
For example, let’s consider a beef burger. LCA quantifies the greenhouse gases emitted to grow crops to feed the cow, the emissions of the cow as it grows, the emissions associated with slaughtering, transportation, storage, and others at the end, giving us the total greenhouse gas emissions generated by a beef burger. The total greenhouse gas emissions are converted to global warming potential, to estimate its potential damages over a certain period of time.
LCA can also evaluate other environmental impacts, such as eutrophication, acidification, land use change, and biodiversity loss.
2. Why is LCA important in understanding climate change solutions?
Three reasons:
1. It’s a systems-thinking method. That is, it quantifies the impact of a product over its entire life-cycle.
2. It is a scientific, evidence-based tool, particularly for estimating the impact on climate change. Since LCA has been established, most LCA research is used to estimate the impacts on climate change, so LCA provides scientific evidence-based results for various products.
3. LCA enables its users to access a large amount of scientific data through databases, and so far, more than 15 databases have been developed, some of which can be country-specific or product-type specific. For example, Agribalyse focuses on foods produced in France, while World Food LCA focuses on foods produced everywhere.
3. What do you like about LCAs, and what got you interested in them?
LCA interested me mainly because I am interested in sustainability, particularly having a sustainable future for many generations on Earth. LCA, with systems- and life-cycle-thinking, can help policy-makers, industry, and consumers to make evidence-based scientific decisions for various products, services, and lifestyles.
4. What are the biggest limitations to LCAs?
One of the main limitations is that even though there has been lots of research conducted to understand the environmental impacts of products, the data is still limited, especially for food products. This is mainly because food production, and its inputs and outputs, can even vary within a country, due to differences in climatic conditions and soil, and also from large and small producers.
Another limitation is that in some impact assessment categories, such as biodiversity loss in marine and freshwater species, and land use change, the methods developed are not fully established—we need more research to improve our understanding.
Another limitation is in the usage phase of LCA. With the development of various databases, its popularity, and ease of use, there are now so many LCA users. However, quantifying impacts with LCA requires a deep understanding of the selected processes in terms of how these processes are modelled, such as type of electricity chosen or amount of pesticide, and also methodological choices such as the functional unit, allocation, and impact assessment model.
5. What do you see as the main findings from LCAs of food and greenhouse gas emissions?
The main findings are that the biggest impacts (approximately 70%) occur typically at the agricultural production stage, and not in the other stages of supply chains, like processing, transportation, and storage. Therefore, consuming local food might not necessarily reduce greenhouse gas emissions. For example, in cold climate countries, some vegetables, such as tomatoes, can only be produced in heated greenhouses, which typically have high energy use and emissions due to heating (this can be around 3kg CO2-eq per kg of tomatoes). For those countries, importing field-grown tomatoes from longer distances might even reduce emissions, as field-grown tomatoes are grown more efficiently (around 0.5 kg CO2-eq per kg of tomatoes).
Among food groups, animal-based foods, such as beef, pork, cheese, and some types of fish/sea food such as shrimp and farmed fish, have higher impacts compared to plant-based proteins, such as pulses and nuts. Therefore, if one wants to reduce the climate impact of their food, that person needs to increase consumption of plant-based proteins while reducing animal-based proteins.
Foods that are transported by airfreight also generate more greenhouse gas emissions compared to food transported by truck, ship, and railway.
6. Is there anything else you’d want dietitians and the general public to know about LCAs or climate-friendly food?
One point is that LCAs of food are typically context-based, i.e., region/country specific, as provided in the local food example with the tomato case, so before making a firm suggestion, I would encourage to have a better understanding of the food systems of the country/region in which the dietitians and their clients live.
LCA of foods can be tricky, because they’re not as straightforward as other non-food products. There are potential differences that might occur along the supply chain of the same food product such as transportation mode (e.g., airfreight), or agricultural production (e.g., heated greenhouses).
Thanks so much to Basak for answering our questions, and for her research work in measuring the climate impact of foods in Canada. I hope this is interesting and helpful!
See you in February,
Anneke