Imagine a world where the carbon footprint of everything—from a bottle of milk to a pension fund investment—was as transparent as a price tag. In such a world, consumers, businesses, and governments could make informed choices, companies could identify ways to reduce emissions and communicate progress, and investors and policymakers could better align decisions with climate goals. While this may sound like science fiction, it's quickly becoming reality. In recent years, efforts to measure carbon footprints have grown rapidly across products, companies, and sectors, supported by new tools, standards, and data. At the OECD, we've tracked this surge—particularly in food systems, which account for one-third of global greenhouse gas emissions when considering the full supply chain. Better data could be transformative, but two key risks remain: fragmented methodologies and high costs for smaller producers, especially in developing countries. Our new OECD report tackles this challenge, exploring how to make carbon footprint measurement in agri-food systems reliable, scalable, and inclusive.
Measuring food-related emissions
Food systems differ from industrial sectors in several ways. They are highly fragmented—with over 600 million farmers worldwide—and include many small and medium-sized enterprises, often in low- and middle-income countries. Most food-related emissions occur early in the supply chain, either on farms or through land-use change, making it essential to understand these stages. Emissions also vary widely: one study found that globally, 25% of producers can account for more than half of total emissions. Data from Ireland shows that the carbon footprint of milk can vary twofold depending on the farmer. These differences reflect factors like climate, soil, farm practices, and technology. That’s why we need farm-level data rather than averages—to recognise sustainable practices and allow this information to flow through the supply chain to consumers. The challenge is doing this in a way that doesn’t create unrealistic burdens for producers.
One important clue comes from private sector initiatives aimed at reducing the reporting burden for Scope 3 emissions. The Partnership for Carbon Transparency has argued that reporting would be much easier if each actor in the supply chain receives reliable carbon footprint data from their suppliers, adds their own emissions, and passes the result on to their customers. In this way, every actor focuses on what they know best (their own emissions), and the full picture emerges step by step along the supply chain.
Eight building blocks are essential
1. Carbon Footprint Reporting Standards: Why Clear Guidelines Matter
Standards define what to include and how to report. The landscape —ISO, GHG Protocol, PEFCR, PACT, LSRG— is complex, but a hierarchy is emerging. More alignment is still needed.
2. Science-Based Methods for Emissions Measurement
Direct measurement isn't practical, with one billion cows worldwide wandering around burping methane. The Intergovernmental Panel on Climate Change (IPCC) provides estimation methods used by countries that are also useful at farm and product levels.
3. Farm-Level Calculation Tools
We need tools to apply scientific methods. Farm-level tools allow farmers to input their activity data. But with over 80 such tools in use, harmonising methods will be key for reliable results.
4. Databases with Secondary Data
When primary data aren’t available, secondary data from life-cycle assessment (LCA) databases can help. But databases vary in methods and coverage. Aligning approaches and filling gaps is crucial.
5. Communicating Carbon Footprint Data Along the Supply Chain
Data must flow seamlessly through the chain. Companies should be able to receive data from suppliers, add their emissions, and pass it on to customers. Several solutions are emerging to facilitate this.
6. Ensuring Data Integrity and Quality
Reliable measurement needs assurance through third-party checks and digital audits. Many schemes only verify whether a methodology was followed, not its appropriateness. More rigorous yet accessible quality control is needed.
7. Scaling Up While Keeping Costs Low
With 60,000 food products in supermarkets, sourced from 600 million farmers worldwide, practical and scalable solutions are essential. One approach is to use secondary data as “default” values first, while working towards more primary data.
8. Continuous Improvement
Initially, we identified seven building blocks, then realised we needed one more: adapting to scientific and technological advancements. The key here is to balance flexibility with stability. A clear timeline for reviewing and updating different initiatives could help.
The Way Forward
The building blocks are falling into place, but there is still work to be done. Many were designed for other purposes, leading to some misalignments. Aligning standards, improving data quality, lowering measurement costs, and keeping up with science will be essential to achieving reliable and widespread carbon footprint measurement in the agri-food sector.
📌 Read the full OECD report: