The numbers side by side
The US average total carbon footprint is approximately 14–16 tons CO₂e per person per year, based on consumption-based accounting data from Exiobase 3.8.2 and EPA national inventory figures. Within that total, food and personal transport are consistently the two largest discretionary categories — meaning the two areas where individual choices have the most direct influence on estimated emissions.
According to Heller and Keoleian (2015), published in the Journal of Industrial Ecology, the average US diet carries an estimated carbon footprint of approximately 2.5 tons CO₂e per person per year from food system emissions — covering land use, production, processing, packaging, transport, and retail. According to the US EPA’s GHG Emission Factors Hub (2025), personal vehicle use in the US averages approximately 2.4 tons CO₂e per person per year, based on average vehicle fuel efficiency and annual mileage data from the Federal Highway Administration.
| Category | US average estimate | High end (heavy use) | Low end (reduced use) |
|---|---|---|---|
| Food (omnivore diet) | ~2.5 tons CO₂e/yr | ~4.0 tons (high beef/dairy) | ~0.5–1.0 tons (vegan) |
| Personal vehicle (petrol) | ~2.4 tons CO₂e/yr | ~4.5 tons (SUV, long commute) | ~0 tons (car-free) |
| Home energy (gas + electricity) | ~3.0 tons CO₂e/yr | ~5.0+ tons (large home, cold climate) | ~0.5 tons (electrified, clean grid) |
| Goods and services | ~3.5 tons CO₂e/yr | ~5.0+ tons (high discretionary spend) | ~1.5 tons (minimal consumption) |
Home energy and goods/services are included for context: while both are larger than food and transport on average, individual variation is higher in food and driving, making them more sensitive to personal choices. The table figures are per-person estimates based on Heller and Keoleian (2015), EPA GHG Hub (2025), and Exiobase 3.8.2; all are estimates, not verified measurements.
~5 tons CO₂e/yr
Combined estimated emissions from food and personal vehicle use for the average US adult — roughly one third of the total US per-person footprint of 14–16 tons CO₂e per year. Sources: Heller & Keoleian (2015); EPA GHG Hub 2025.
Where the emissions actually come from in each category
Food: production dominates, transport barely registers
Within food emissions, the split between production stages is highly unequal. According to Poore and Nemecek (2018) in Science, land use change and farm-level production account for approximately 80% of total food system emissions on average. Processing, packaging, transport, and retail together account for the remaining 20%, with transport alone contributing only about 6%. This means that switching from imported to locally grown food of the same type produces a negligible emission saving, while switching from beef to legumes — regardless of origin — produces a large one.
Beef and lamb are the dominant drivers within food emissions. Poore and Nemecek (2018) estimate that beef carries lifecycle emissions of approximately 25–105 kg CO₂e per 100 grams of protein depending on production system, compared to roughly 1.8 kg CO₂e per 100 grams of protein for tofu. A US adult eating beef four times per week contributes materially more food-related estimated emissions than one eating beef once per week — the difference can exceed 1 ton CO₂e per year.
Transport: mileage and vehicle type are the key variables
For personal vehicle emissions, two variables dominate: annual mileage and vehicle fuel efficiency. The US EPA GHG Hub (2025) puts the average passenger car emission factor at approximately 0.21 kg CO₂e per kilometre for a typical petrol vehicle. At the US average of around 15,000 miles (24,000 km) driven per year, this yields approximately 5 tons CO₂e — but this is a per-vehicle figure. Per person in multi-driver households, the number falls to around 2.4 tons CO₂e.
An SUV or light truck — which represent over half of new vehicle sales in the US — carries emission factors roughly 30–50% higher than a compact car, according to EPA fuel economy data. At the same annual mileage, an SUV driver produces approximately 0.7–1.2 additional tons CO₂e per year compared to a compact car driver. Switching to an EV reduces direct driving emissions to near zero at point of use, shifting remaining emissions into grid electricity (Scope 2) where they fall further as the grid decarbonises.
A useful comparison
According to Poore and Nemecek (2018) and EPA eGRID 2023 data, shifting from an average omnivore diet to a vegan diet saves approximately as much estimated CO₂e per year as eliminating 4,000–6,000 miles of average US car driving. Both actions are in the same order of magnitude — roughly 1–2 tons CO₂e per year — which is why personal footprint calculators that cover both categories produce more accurate and actionable results than those that cover only one.
Which to tackle first
The right answer depends on your specific situation. A useful framework is to start with whichever category is furthest above the average — high beef consumption or high annual mileage — since that is where the largest absolute reduction is available. The steps below reflect general priority order for someone near the US average in both categories.
Estimate your current footprint in both categories. Without a baseline, you cannot tell whether your food or transport emissions are above or below average, or where the largest reduction opportunity lies. A calculator that covers both — including diet type and annual mileage — gives you the comparison that makes prioritisation possible.
Reduce beef and lamb first in the food category. Ruminant meat has a disproportionate share of food-related estimated emissions. Replacing beef with chicken reduces protein-equivalent food emissions by approximately 75%; replacing it with legumes reduces them by over 90%, according to Poore and Nemecek (2018). Partial reduction — cutting beef frequency rather than eliminating it — still produces meaningful savings.
Reduce unnecessary mileage and optimise vehicle choice in the transport category. Consolidating trips, shifting some commuting to public transport or cycling, and choosing a more fuel-efficient vehicle (or an EV) are the highest-leverage transport actions. For drivers above the US average mileage, trip reduction may produce larger near-term savings than vehicle switching.
Do not overlook flights. A single long-haul return flight can add 1–2 tons CO₂e to your annual footprint — equivalent to months of food or driving emissions. For frequent flyers, aviation may exceed either food or personal vehicle use as a category and should be assessed alongside both.
For a full breakdown of diet emissions by food category, see the Decarb post on how much CO₂ a vegetarian diet saves per year. For a detailed look at how vehicle type and mileage interact, visit decarb.co/methodology.
Frequently asked questions
Is food or driving worse for your carbon footprint?
For the average US adult, food and driving contribute roughly similar estimated emissions — approximately 2.4–2.5 tons CO₂e per year each, based on Heller and Keoleian (2015) and EPA GHG Hub (2025) data. Which is larger depends on individual habits: a high-beef diet combined with modest driving tips toward food; a low-meat diet combined with a long SUV commute tips toward transport.
How much of the average US carbon footprint comes from food?
Food accounts for approximately 15–20% of the average US per-person carbon footprint of 14–16 tons CO₂e per year, based on consumption-based accounting using Heller and Keoleian (2015) and Exiobase 3.8.2 data. At roughly 2.5 tons CO₂e per year, it is the third-largest category after goods and services and home energy, and broadly comparable to personal vehicle use.
Does reducing beef save more emissions than driving less?
It depends on how much beef you eat and how much you drive. Eliminating beef entirely from an average US omnivore diet saves roughly 0.5–1.0 tons CO₂e per year, according to Poore and Nemecek (2018). Eliminating 5,000 miles of average US car driving saves approximately 0.5 tons CO₂e. The two actions are broadly comparable in magnitude, which is why the answer to “food or car first” depends on which is larger in your specific situation.
How do flights compare to food and driving emissions?
A single transatlantic return flight contributes an estimated 1.5–2.5 tons CO₂e per passenger using ICAO ICEC methodology, which is roughly equivalent to six months of average US food emissions or six months of average driving. For frequent flyers — defined loosely as those taking more than two long-haul flights per year — aviation can exceed both food and driving as the largest single category.
What is the single most effective change to reduce food and transport emissions together?
There is no single action that reduces both simultaneously, but the highest combined leverage comes from reducing beef consumption and reducing unnecessary driving mileage — specifically long solo car trips that could be consolidated or replaced with public transport. Together, cutting beef frequency by half and reducing annual mileage by 3,000–4,000 miles can save approximately 0.7–1.2 tons CO₂e per year without requiring any capital investment in new equipment.
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Sources
- Heller, M.C. & Keoleian, G.A. “Greenhouse Gas Emission Estimates of U.S. Dietary Choices and Food Loss.” Journal of Industrial Ecology 19(3), 391–401. 2015. DOI: 10.1111/jiec.12174
- Poore, J. & Nemecek, T. “Reducing food’s environmental impacts through producers and consumers.” Science 360(6392), 987–992. 2018. DOI: 10.1126/science.aaq0216
- US EPA. GHG Emission Factors Hub 2025. US Environmental Protection Agency, 2025.
- US EPA. Emissions & Generation Resource Integrated Database (eGRID) 2023. US Environmental Protection Agency, 2024. epa.gov/egrid
- Stadler, K. et al. “Exiobase 3: Developing a Time Series of Detailed Environmentally Extended Multi-Regional Input-Output Tables.” Journal of Industrial Ecology 22(3), 502–515. 2018.
- ICAO. ICAO Carbon Emissions Calculator (ICEC) Methodology. International Civil Aviation Organization, 2023.
- US Federal Highway Administration. Highway Statistics 2023: Annual Vehicle Distance Travelled. FHWA, 2024.
