The projected increase in the production and consumption of animal products is likely to put further pressure on the globe’s freshwater resources. The size and characteristics of the water footprint vary across animal types and production systems.
The water footprint of meat from beef cattle (15400 m3/ton as a global average) is much larger than the footprints of meat from sheep (10400 m3/ton), pig (6000 m3/ton), goat (5500 m3/ton) or chicken (4300 m3/ton). The global average water footprint of chicken egg is 3300 m3/ton, while the water footprint of cow milk amounts to 1000 m3/ton (Mekonnen and Hoekstra, 2010).
Per ton of product, animal products generally have a larger water footprint than crop products. The same is true when we look at the water footprint per calorie. The average water footprint per calorie for beef is twenty times larger than for cereals and starchy roots. When we look at the water requirements for protein, it has been found that the water footprint per gram of protein for milk, eggs and chicken meat is about 1.5 times larger than for pulses. For beef, the water footprint per gram of protein is 6 times larger than for pulses. In the case of fat, butter has a relatively small water footprint per gram of fat, even lower than for oil crops. All other animal products, however, have larger water footprints per gram of fat when compared to oil crops. From a freshwater resource perspective, it is more efficient to obtain calories, protein and fat through crop products than animal products.
The water footprint of some selected food products from vegetable and animal origin.
Source: Mekonnen and Hoekstra (2010)
Global animal production requires about 2422 Gm3 of water per year (87.2% green, 6.2% blue, 6.6% grey water). One third of this volume is for the beef cattle sector; another 19% for the dairy cattle sector. Most of the total volume of water (98%) refers to the water footprint of the feed for the animals. Drinking water for the animals, service water and feed mixing water account only for 1.1%, 0.8% and 0.03%, respectively (Mekonnen and Hoekstra, 2010).