Author: Miguel Van Damme & Bieke Vandaele
With the ever-growing flow of information on environmental issues and climate change, it becomes hard to keep track. To grasp the bigger picture, it is best to learn about one subproblem at the time. In this article the topic is food sustainability: How can we reduce the environmental impact of food? What are the main problems we need to consider? What is the impact of our daily habits?
Impact of agriculture goes beyond GHG emissions
A good starting point is to look at the influence of food on the earth’s natural resources. The graph below shows how food and agriculture impact the environment, compared to non-food influences. Food and agriculture are responsible for a quarter of the global greenhouse gas emissions (GHG), 50% of the land use and 70% of the freshwater use. Agriculture is responsible for 78% of the eutrophication (overload of nutrients, leading to excessive growth of algae) of oceans and freshwater resources. Livestock outweighs wild biodiversity by a factor of 15 to 1. Taking a closer look at the global greenhouse gas emissions shows that 31% of the emissions in food production come from livestock and fisheries, 27% comes from crop production, 24% from land use and 18% from supply chains. (1) While some readers might already be aware of these statistics, it is not the exact numbers that are important. The key to achieving impact as an individual, is to know how these numbers relate to our daily habits.
Types of GHG
In food production, CO2 is not the only greenhouse gas that is emitted. There is also methane and NO2 that are for example produced by the ruminant digestion and rice cultivation. The impact of the production phase in the food industry is not to be underestimated land use and farm-stage emissions make up 80% of the total emissions for most foods. As a consequence, emissions for animal-based foods are that much higher than for plant-based foods. They require an extra processing step from the plant-based animal feed to an animal-based product, accumulating emission over the whole process. In fact, their emissions are so significant that replacing, only part of, your meat-based diet with plant-based products offers more environmental benefits than locally sourcing your food. (2) (3)
Global vs Local Sourcing
Surprisingly, the key rule is not always to buy local. While transport does contribute to the CO2-footprint of products, for food this is only significant when it is imported by airfreight. This is the case for products with a short lifetime and a long distance to travel, like berries, green beans, asparagus, … (4) For products well suited to a specific climate and with a longer lifetime, it is more CO2-efficient to import them by boat than to produce them locally in every country. For example, producing tomatoes in Swedish greenhouses requires ten times the energy that is needed to produce the same tomatoes in Southern Europe and then import them to Sweden. (5)
Freshwater resources are decreasing every year and agriculture is the biggest consumer. Highly irrigated crops or foods with many processing steps require the most water. Meat production, for example, requires about ten times the amount of water needed for cereals, fruit or vegetables. Other products that are less known to be gluttons of water resources, are nuts and coffee. Due to the way the beans are cultivated, a cup of coffee requires 140L of water for a cup of 125mL. (6) (7)
The environmental impact of food is not only limited to its production. A quarter of the calories the world produces, are wasted every year, with 15% being lost in the supply chain and 9% lost by retailers, restaurants and consumers. The main reasons why food is wasted are overproduction, overbuying and spoilage. An important figure here is that food waste is responsible for about 6% of global greenhouse gas emissions which is about 3 times the global emissions caused by aviation. (2) (8)
Define your own guidelines
Acquiring a broad overview of all aspects of environmental impact related to food requires a lot of research and can be overwhelming at times. As a consumer, set a couple of guidelines for yourself that are easy to remember: Eat plant-based dinner once or twice a week, think about the seasonality and origin of your fruits and vegetables, take coffee out of your morning routine, … These guidelines will help you to be aware of the impact of your diet and push you to improve one step at the time. Finally, remember that a conscious approach to food will help you to reconsider how much food you buy and as such reduce your food waste as well.
(1) Hannah Ritchie, Max Roser (2020), Environmental impacts of food production, Our world in data https://ourworldindata.org/environmental-impacts-of-food
(2) Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987-992.
(3) Weber, C. L., & Matthews, H. S. (2008). Food-miles and the relative climate impacts of food choices in the United States. Environmental Science & Technology.
(4) Hannah Ritchie, You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local, our world in data, https://ourworldindata.org/food-choice-vs-eating-local
(5) Carlsson-Kanyama, A., Ekström, M. P., & Shanahan, H. (2003). Food and life cycle energy inputs: consequences of diet and ways to increase efficiency. Ecological Economics, 44(2-3), 293-307.
(6) Mekonnen, M.M. and Hoekstra, A.Y. (2012) A global assessment of the water footprint of farm animal products, Ecosystems, 15(3): 401-415.
(7) A.K. Chapagain, A.Y. Hoekstra (2007), The water footprint of coffee and tea consumption in the Netherlands, Ecological economics, 64: 109-118
(8) M. Ge, J. Friedrich, (2020) 4 Charts Explain Greenhouse Gas Emissions by Countries and Sectors, World Resource institute, https://www.wri.org/blog/2020/02/greenhouse-gas-emissions-by-country-sector