Food · emission factor
The Carbon Footprint of Beans
100 g CO₂e / 100g
Beans have a carbon footprint of about 100 g CO₂e per 100 g, based on the global life-cycle analysis by Poore & Nemecek (2018, Science). That makes them one of the lowest-emission protein sources available — roughly 30 times lower than beef per unit weight and well below chicken, eggs, or cheese. For anyone trying to cut food-related emissions without cutting protein, beans are close to the best deal on the plate.
Why beans have such a low footprint
Beans avoid the two biggest drivers of food emissions: ruminant methane and heavy land use. Unlike cattle or sheep, no animal digestion is involved, so there is no enteric methane. And unlike animal protein generally, there is no feed-conversion loss — the crop you grow is the food you eat, rather than feeding grain to livestock that returns only a fraction of those calories. Legumes also fix nitrogen from the air through symbiotic bacteria in their root nodules, which reduces the need for synthetic nitrogen fertilizer — a significant emissions source in most cropping, both from its energy-intensive manufacture and from nitrous oxide released in fields. The main remaining emissions come from farm machinery, processing, packaging (especially canning), and transport, which together still add up to only around 100 g CO₂e per 100 g.
How beans compare with other proteins
Per 100 g, beans at 100 g CO₂e sit far below every animal protein in the same dataset: beef is about 2,990 g (roughly 30x), lamb 2,420 g, cheese 1,350 g, pork 1,220 g, chicken 620 g, fish 550 g, and eggs 450 g. Even tofu, another excellent plant protein, comes in at around 200 g. The gap matters at scale: livestock accounts for roughly 14–15% of global greenhouse gas emissions according to the FAO, and food overall for about a quarter. Swapping one beef-based meal per week for a bean-based one saves on the order of 3 kg CO₂e per typical serving — comparable to skipping a 15 km drive in a petrol car.
Do canned or dried beans matter?
Dried beans generally have the lowest footprint, since canning adds steel or aluminium packaging and cooking energy at the factory. But the difference is small compared with the gap between beans and meat, so canned beans remain a very low-carbon choice — convenience should not stop anyone using them. Home cooking energy matters too: dried beans need long simmering, so a pressure cooker, which cuts cooking time by two-thirds or more, is the efficient option. Transport is a minor factor, as beans are dry, dense, and shipped by sea or land rather than air. Wherever they come from and however they are packed, beans stay firmly at the low end of the food-emissions scale.
How beans compares
How to reduce this footprint
- ✓ Swap beans for beef or lamb in chili, tacos, or bolognese — each swap cuts that meal's protein footprint by roughly 95%.
- ✓ Buy dried beans and cook them in batches with a pressure cooker to minimize packaging and cooking energy.
- ✓ Freeze cooked beans in meal-sized portions so low-carbon protein is as convenient as anything processed.
- ✓ Track your meals in Decarbonr to see how bean-based dishes lower your weekly food footprint over time.
Frequently asked questions
Are beans really better for the climate than meat?
Yes, by a wide margin. Beans emit about 100 g CO₂e per 100 g versus roughly 2,990 g for beef and 620 g for chicken, per the Poore & Nemecek (2018) global dataset. That makes beans about 30 times lower-carbon than beef for the same weight.
Why do beans have such a low carbon footprint?
Legumes fix their own nitrogen, cutting the need for synthetic fertilizer, and involve no animal methane or feed-conversion losses. Their main emissions come from farming machinery, processing, and packaging, which together stay around 100 g CO₂e per 100 g.
Do beans provide enough protein to replace meat?
Cooked beans deliver roughly 8–9 g of protein per 100 g along with fiber and iron, and combined with grains they supply all essential amino acids. Regularly replacing meat with beans is nutritionally sound for most people and one of the most effective single food swaps for reducing emissions.
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Sources & methodology: see Research & scientific references. Figures are averages used by the Decarbonr app; real-world values vary by production system, country, and occupancy.