Compare the transport-mile footprint of buying local vs conventional grocery — with CO2e estimates.
kg CO₂e per meal
0.100 kg per ton-mile
0.150 kg
Ton-miles
1.500
Local-farm baseline (same weight, 50 mi)
0.001 kg
Delta vs local farm
+0.149 kg
Equivalent car miles
At ~0.4 kg CO₂e per mile
0.38 mi
Transport is only one slice of food's footprint, but it is the slice that is most obviously fixable at the grocery level. Ocean shipping is remarkably efficient per ton-mile; air freight is about 100× worse and shows up in off-season berries and premium seafood.
Production emissions (especially beef, lamb, cheese) usually dwarf transport emissions. But for produce that is in season locally, short-haul really does win on every axis — freshness, price, and footprint.
ton-miles = (weight_lb ÷ 2000) × miles
kg_CO₂e = ton-miles × mode_factor
Mode factors (kg CO₂e / ton-mile): truck 0.1 · plane 1.5 · ship 0.015 · local-farm 0.02