Water footprint of beef production - critical review of current approaches

Beef is one of the most valuable food commodities which is reflected in the high international trade volume. Global demand for beef has been rising consistently over the last five decades. About one third of all agricultural land on the globe is wholly or partially occupied by beef production systems. Beef production is, next to crop irrigation, probably the largest water consumer of all food production systems. It is also reputed to have severe environmental impacts through water depletion, contamination, and negative effects on local and regional hydrology. Current estimates for the embedded water contained in 1 kg of boneless beef range from 10 to 100 m³. Total bovine numbers on the globe are estimated at close to 1.5 billion head with a total live biomass of 500 to 600 million metric tons. 500 million tons live bovine biomass would represent approximately 175 million tons of boneless beef. This would in turn stand for 1.75 million km³ embedded water if the most conservative estimate were used. Life time drinking water of cattle is only 1% or less of this amount. The remainder, aside from some negligible amounts for management and product processing, is water needed for the production of feeds and forages. The wide range of estimates for embedded water (virtual water) is explainable through various factors: biophysical, climatic, production systems related, regional characteristics, or just reflecting the accounting assumptions used. The paper examines these factors and their effects on water demand estimates. A procedure is suggested which allows to evaluate water demand on the production system level in such way that this can be used as a management tool on the enterprise scale. This could open a considerable potential to reduce reputed water demand for beef production.