Global and multiyear assessment of the water footprint of farm animal products

In recent years, there has been a marked increase in the consumption of animal meat within human food diets. In addition, the considerable importance that the livestock sector plays towards the consumption of natural resources is ascertained, among which water is one of the main ones. To the aim of this study, the unit water footprint of farm animal products was calculated, and the volumes necessary to produce them were listed. The analysis spans a time frame from 1986 to 2016, and detailed information on the diet of the animals and the yields of crop products they feed on has been carefully conducted. Results, which have been obtained on a national scale, show the temporal evolution of the uWF and in what percentage the water coming from irrigation systems (blue water) is used. The effect of the trade in animal feed on the water footprint of the derivative products was also investigated, comparing the results with an hypothetical scenario in which there is no expected trade in the world. Results show a general increase in the water efficiency of the products, up to having cases where the uWF decreases by about 50% in the thirty years. However, due to the substantial increase in the tons produced, the volumes of water consumed increase over time; the percentage of blue water, however, remains approximately constant. Finally, the effect of the trade is to reduce the unit water footprints of all animal products, even if only litte, except for pigs, for which these increase slightly.