What the Numbers Mean

With the defaults (average global diet, 2,000 kcal/day), the footprint is 5.50 kg CO2e per day — about 2.01 tons per year. That equals roughly 101 trees' annual absorption capacity and is the benchmark every other diet is compared against.

From Oxford, Not Guesswork

The emission factors come from Scarborough et al. 2014, a University of Oxford study of 55,000+ diets. The gap between a meat-heavy diet (7.19 kg/day) and a vegan diet (2.89 kg/day) is about 60% — the single largest lever most people have on their food footprint.