The carbon footprint of the food supply chain

Over a quarter of the world’s greenhouse gas emissions come from food production (*1). How food is produced, processed and transported, can have a big impact on our personal carbon footprint and the carbon emissions that food businesses are responsible for. Food businesses are increasingly reporting their carbon emissions, either as product carbon footprints or value chain / Scope 3 emissions.

Reliable measurement of which parts of the food supply chain are the big emitters is the first and most important step towards ameliorating the impact of our modern diet and common farming practices on climate. For example, food miles are often touted as the answer when it comes to lowering the carbon footprint of the food industry. But when we measure greenhouse gas emissions from the entire supply chain from farm to fork, transport is typically responsible for only a small fraction of emissions. 

In the largest meta-analysis of global food systems to date, published in Science, researchers looked at data from more than 38,000 commercial farms in 119 countries (*2). They examined the greenhouse gas emissions of carbon, methane and nitrous oxide, per kilogram of food product. The study’s findings, summarised below, make for interesting reading.

Land use

Nearly a quarter of global greenhouse gas emissions from food production are directly linked to changes in land use. When forests and grasslands are cleared to make way for farming, there are often significant immediate emissions from the loss of biomass above ground, furthermore the land loses its ability for on-going absorption of carbon through above ground biomass such as trees and shrubs, and below ground changes in soil carbon.

Two thirds of land use emissions result from land clearance for rearing of livestock – either for livestock grazing or to grow crops for animal feed. 

Farming practices such as biomass burning and soil cultivation through tilling, also contribute significant carbon emissions.

Livestock

Livestock production, which includes animals raised for meat, dairy, eggs, and seafood production, account for 31% of food emissions. Not surprising this is, considering livestock production takes up nearly 80% of global agricultural land. The big emitters in terms of overall scale across the livestock categories – and also per unit of protein – are ruminant livestock, especially cattle, which produce methane through their digestive processes. Manure management and pasture management are also significant GHG contributors in the farming practices for livestock. Livestock production also incurs a material amount of  GHG emissions from land use along with the production of animal feed crops. 

Crop production

21% of food sector emissions come from crop production for direct human consumption, with a further 6% coming from crops grown for animal feed (*3). Agricultural machinery usage, fertiliser production and usage and manure are all sources of on-farm emissions. The common practice of  flooding in rice production produces significant amounts of methane.

Food manufacturing, retail and waste

Once food products have moved off farm, the energy and resources needed to process them and get them to retailers can be significant. This segment of the supply chain accounts for 18% of food emissions. And while eating locally is often proposed as the key to a low-carbon diet, transport emissions account for just 6% of global food emissions.

Better processing, packaging, and transporting of food products to distant markets can also help to reduce the emissions caused by food waste. One quarter of overall emissions – 3.3 billion tonnes of CO2 equivalent – from food production ends up wasted. Durable packaging, better cold chain management and food processing, all help to prevent food waste. For example, fruit and vegetables that have been frozen or canned have a wastage rate about 14% lower than items bought fresh, which often end up in the bin (*4). 

Reducing emissions: insights and challenges

A fundamental insight for the carbon footprint of the food supply chain is that the majority of greenhouse gas emissions originate at the very start of a food product’s lifecycle (activities occurring on farm, and land use associated with the farmed land). Later activities in the food supply chain - such processing, packaging, transport and retail - are typically much lower contributors to the carbon footprint. With many food manufacturers and retailers now seeking to reduce the greenhouse gas emissions of the food products they sell, there is a fundamental need to understand on-farm activities as a means to more reliably measure and then drive continuous improvement programmes for climate and other sustainability impacts. 

Different foods have vastly different carbon footprints. Production of 1kg of beef typically embodies emissions of 60kg of greenhouse gases along the value chain, whereas the same 1kg amount of peas emits just 1kg of greenhouse gases (*5).  Beef therefore has a 60x higher carbon footprint than peas when compared as a measurement per unit of product weight. 

Comparing alternative products by weight can be helpful. Another way to measure and compare product carbon footprints is to consider the human nutritional perspective – which is a primary ‘utility’ of being provided from the food product. For example, 1kg of protein from beef is, as a global average, responsible for 83kg of greenhouse gas, whereas the equivalent 1kg of protein from peas involves 2kg of greenhouse gases. So from a protein perspective, the greenhouse gas emissions of beef is 40x higher than for peas.

A key consideration for food businesses sourcing globally in an open commodity market, is the country of production. There are significant variations on the average product carbon footprint of the same product category, when supplied from different regions – reflecting the most common farming practices and land management within the supplying region. Staying with our beef example, according to the meta-analysis study, whilst the global average for 1kg of beef is 60kg of greenhouse gases, when produced in the USA the product carbon footprint is a much improved 37kg. If produced from Europe the beef product carbon footprint is even lower at 14kg. 

Similarly, there are material differences in the emissions intensity of primary agricultural productions depending on the specifics of each producing farm. For example the local setting – such as local climate, soil qualities, fresh water abundance – but also the farming practices, such as land management, residue and waste approaches, farm input choices and application methods, crop mix and rotations and animal husbandry practices. Many food businesses are wanting to engage with growers and support the adoption of lower carbon footprint practice where most relevant.

So a food business that is buying agricultural products and seeks to measure and reduce its value chain – Scope 3 – emissions, will need to collect data from and evaluate the impact of its own supply chain and not rely on industry averages. 

Measuring Sustainability Credentials 

With this in mind, there is certainly no one-size-fits-all solution to reducing the carbon footprint of a food business’s supply chain.

Instead, a comprehensive toolkit of solutions is needed – starting with measurement tools then exploring a range of available improvement options, including everything from changes to diets, to new ways to reduce food waste, to improvements in agricultural efficiency. New innovations like seaweed supplements, which are being fed to cattle to significantly reduce their methane emissions, are a positive step forward. As are the emerging technologies that make low-carbon food alternatives scalable and affordable. All of these things will help play a part in making our food industry more sustainable.

Reducing carbon emissions from food production is one of the greatest challenges facing food producers today. There’s never been a more critical need for food businesses to adopt reliable and detailed measurement of greenhouse gas in their supply chain – back to primary production – and to highlight the potential and achieved reductions from a well-informed sustainability programme.  

TELUS Agriculture & Consumer Goods can help. Sustainability Management uses robust sustainability evaluations, smart benchmarking and data-driven insights to help you transform your supply chain sustainability programme beyond compliance. Find out more about our Sustainability solution by downloading our brochure, or request a solution demonstration today.

References 

1. Our World in Data, 2021, Environmental impacts of food   
2. Reducing food’s environmental impacts through producers and consumers - Science
3. Our World in Data, 2021, Environmental impacts of food   
4. Our World in Data, 2021, Environmental impacts of food   
5. The most common unit used for measuring greenhouse gases is kg of CO2 equivalent (CO2e)