The water footprint of humanity
The global annual average water footprint (WF) in the period 1996-2005 was 9,087 Gm3ây (74% green, 11% blue, 15% gray). Agricultural production contributes 92%. About one-fifth of the global WF relates to production for export. The total volume of international virtual water flows related to trade in agricultural and industrial products was 2,320 Gm3ây (68% green, 13% blue, 19% gray). The WF of the global average consumer was 1,385 m3ây. The average consumer in the United States has a WF of 2,842 m3ây, whereas the average citizens in China and India have WFs of 1,071 and 1,089 m3ây, respectively. Consumption of cereal products gives the largest contribution to the WF of the average consumer (27%), followed by meat (22%) and milk products (7%). The volume and pattern of consumption and the WF per ton of product of the products consumed are the main factors determining the WF of a consumer. The study illustrates the global dimension of water consumption and pollution by showing that several countries heavily rely on foreign water resources and that many countries have significant impacts on water consumption and pollution elsewhere (Hoekstra and Mekonnen, 2012).
This study has recently been picked up by the blogger of "What Our Water's Worth"
To read the article: bit.ly/WPazmf
Hoekstra, A.Y. and Mekonnen, M.M. (2012) The water footprint of humanity, Proceedings of the National Academy of Sciences, 109(9): 3232-3237.