Water is an essential resource for global food security. According to the Food and Agriculture Organization (FAO), it takes 3,000 litres of water to produce food for one person’s daily needs, whereas up to 15,000 litres are needed for the production of 1 kg of meat.[1]

Other data sources find:

• 2,714 litres of freshwater withdrawal per kilogram of beef (dairy herd);
• 1,451 litres per kilogram of beef (beef herd);
• 660 litres per kilogram of poultry meat, and;
• 628 litres per kilogram of milk.[2]

These different estimates relate to scoping differences, depending on whether they focus on blue water (surface and ground freshwater) footprint only, or include also green water (soil moisture from precipitation used by plants) and grey water (used water that contains impurities) footprint.

The cultivation of soy also requires a large amount of water. While water use can be reduced when rainwater is available, the soy global water footprint is currently estimated to be 2,145 litre/kg.[3] 

In comparison, the review of water use across alternative proteins reveals that algae, particularly microalgae and macroalgae farmed in seawater, demonstrate unequivocally better outcomes in terms of water efficiency compared to conventional proteins. While there are uncertainties in the data, notable potential for improvement is possible for microbial fermentation and cultured meat, with the latter likely to use significantly less water than beef production and potentially comparable amounts to poultry production.

Algae

Insects

Microbial fermentation

Cultured meat