Cow's milk vs Oat milk
Every plant milk beats dairy on all three environmental axes. Oat is the strongest all-rounder: low water use, temperate growing regions and no almond-style irrigation pressure.
Per per litre
Greenhouse gaseskg CO₂e / L
Cow's milk
3.2
Oat milk
0.9
Land usem² / L
Cow's milk
9
Oat milk
0.8
Freshwater withdrawalL / L
Cow's milk
628
Oat milk
48
Calcium (fortified)mg / 100 ml
Cow's milk
120
Oat milk
120
Source: Poore & Nemecek (2018), Science · Our World in Data · USDA FoodData Central
Verdict
Oat milk uses about a third of the emissions and a tenth of the land.
Questions people ask
Which plant milk is lowest impact overall?
Oat and soy. Soy adds the most protein; oat uses the least water among common options.
Is fortified oat milk nutritionally comparable?
For calcium, B12, D and iodine, fortified versions match or exceed dairy. Protein is lower — soy milk closes that gap.