Food · emission factor
The Carbon Footprint of Nuts
200 g CO₂e / 100g
Nuts have a carbon footprint of about 200 g CO₂e per 100g, based on Poore & Nemecek's 2018 global analysis published in Science. That makes them one of the lowest-emission protein and fat sources available — roughly 15 times lower than beef and about a third of chicken per unit weight. Some analyses even find certain tree nuts approach net-zero or negative emissions when orchard carbon storage is counted.
Why nuts have such a low footprint
Most nuts grow on long-lived trees — almond, walnut, hazelnut and cashew orchards stand for decades. Those trees absorb and store carbon in trunks, branches and roots while they produce food, which offsets much of the emissions from fertilizer, machinery and processing. Unlike livestock, nuts involve no enteric methane and no feed-crop supply chain, the two factors that push beef to 2,990 g CO₂e per 100g. Land-use change is the main variable: where forest is cleared for new plantations (a concern with some cashew and cocoa-adjacent regions), the footprint rises. Peanuts, technically legumes, fix their own nitrogen and typically need less synthetic fertilizer, keeping their footprint at the low end of the range.
How nuts compare with other protein sources
At 200 g CO₂e per 100g, nuts sit alongside tofu (200 g) and olive oil (200 g), just above beans (100 g) and well below eggs (450 g), fish (550 g) and chicken (620 g). Against ruminant meat the gap is dramatic: lamb emits about 12 times more and beef about 15 times more per 100g. Since food overall drives roughly a quarter of global greenhouse gas emissions — with livestock alone accounting for about 14–15% per the FAO — swapping even part of your meat-based protein for nuts is one of the highest-leverage dietary changes available. Per gram of protein the comparison narrows slightly, because nuts are fat-rich, but they remain firmly in the low-carbon tier.
The water caveat
Carbon is only one dimension. Almonds in particular are water-intensive — a single almond takes roughly 3–4 litres of water to grow, and most of the world's supply comes from drought-prone California. Cashews and pistachios also have notable water footprints. From a purely climate perspective nuts are excellent; from a water-stress perspective, provenance matters. Peanuts, hazelnuts and walnuts generally require less irrigation. If you want to optimize both, favor rain-fed or regionally grown nuts, and treat almonds as a low-carbon but water-costly choice rather than a free pass.
How nuts compares
How to reduce this footprint
- ✓ Swap part of your meat-based snacking or protein for nuts — replacing 100g of beef with nuts avoids roughly 2.8 kg CO₂e.
- ✓ Choose peanuts or regionally grown hazelnuts and walnuts if water use concerns you as much as carbon.
- ✓ Buy nuts in bulk with minimal packaging, since packaging and transport are a small but avoidable share of their footprint.
- ✓ Log your meals in a tracker like Decarbonr to see how nut-based swaps change your weekly food footprint.
Frequently asked questions
Are nuts really better for the climate than meat?
Yes, by a wide margin. Nuts emit about 200 g CO₂e per 100g versus 2,990 g for beef and 620 g for chicken. Tree nuts avoid livestock methane entirely, and orchards store carbon while they grow.
Which nuts have the lowest carbon footprint?
Peanuts are typically lowest because they fix their own nitrogen and need little fertilizer, while most tree nuts cluster around the same 200 g CO₂e per 100g average. The bigger differentiator is water: almonds and cashews are far thirstier than peanuts or walnuts.
Do almonds have a bad environmental footprint?
For carbon, no — almonds sit near the low 200 g CO₂e per 100g nut average. Their issue is water: growing one almond takes roughly 3–4 litres, mostly in drought-prone California, so they are a climate-friendly but water-intensive food.
Track this automatically
Decarbonr turns meals and journeys into one clear daily CO₂e number — on your iPhone, on-device, private by design.
Free trial · then subscription · AI scanning optional add-on
Sources & methodology: see Research & scientific references. Figures are averages used by the Decarbonr app; real-world values vary by production system, country, and occupancy.