Does almond milk use more water than dairy?

The objection

“Almond milk drinks the rivers dry, it takes a small lake to make a glass. Dairy’s the greener choice, honestly.”

The answer

Almond milk is the thirstiest of the plant milks in Poore and Nemecek’s data (2018) [2], and its water often comes from places that can least spare it. Vanham and colleagues (2020) found that 0.9 million of the 1.0 million tonnes of irrigated almonds in their data, which covered 1996 to 2005, were grown under water stress, most of it severe, with California, in the US, the largest hotspot [5].

Does almond milk use more water than cow’s milk?

Not in Poore and Nemecek’s 2018 dataset, built from some 38,700 farms, where a litre of almond milk draws about 371 litres of fresh water and a litre of cow’s milk about 628 [1][2], though studies that count water in other ways often put almond milk higher [4]. That is roughly 90 litres for a 250ml glass of almond milk and 160 for one of cow’s milk. Poore and Nemecek’s figures are global averages of withdrawals, which count all the fresh water drawn to make each drink whether or not it later returns to a river [4]. Other studies count only the blue water footprint, meaning surface and groundwater such as irrigation water that evaporates or ends up in the product, and some weight water by how scarce it is where it was drawn [4]. Cow’s milk carries the water that grew the cow’s feed, and Mekonnen and Hoekstra (2012) found that the poor conversion of feed into food is largely why animal products have bigger water footprints than crops of equivalent nutritional value [6].

Is almond milk worse once protein and scarcity are counted?

A 2023 review of life-cycle studies by Ramsing and colleagues found almond milk’s water use was often the highest of the milks compared, particularly when weighted for local water scarcity or counted per gram of protein [4]. Its abstract names almond milk’s higher water footprint as the notable exception to plant milks’ generally lower impacts than cow’s milk [4]. Our World in Data (2022) puts cow’s milk at about 3.4g of protein per 100ml and almond milk at about 0.5g [3], so on Poore and Nemecek’s water figures almond milk needs about four times as much water per gram of protein. Scarcity weighting gives more weight to water drawn in a dry region such as California, and the review’s authors conclude that almond milk’s water footprint can be substantially higher than cow’s milk’s, especially when almond milk made in California is set against dairy from somewhere wetter [4].

Which plant milk uses the least water?

Soy milk uses the least, about 28 litres a litre, followed by oat milk at 48, each under a twelfth of cow’s milk’s 628; rice milk takes 270 [2]. Of the four, soy milk also comes closest on protein. In US Department of Agriculture figures (2019) for US products, compiled in the 2023 review, a 240ml glass has 6.1g against 8.2g for cow’s milk, 2.7g for oat milk, 1.0g for almond milk and 0.7g for rice milk [4]. On the dataset’s other three measures almond milk does well, with a litre of cow’s milk producing about four and a half times its greenhouse gas emissions, using 18 times its land and causing about seven times its nutrient pollution of water [2]. Every plant milk there beats cow’s milk on all four measures, though none is lowest on every one. Almond milk has the lowest emissions, rice milk the smallest land use, and soy milk the least water use and nutrient pollution [2][3].