The water footprint of humanity

Abstract

This study quantifies and maps the water footprint (WF) of humanity at a high spatial resolution. It reports on consumptive use of rainwater (green WF) and ground and surface water (blue WF) and volumes of water polluted (gray WF). Water footprints are estimated per nation from both a production and consumption perspective. International virtual water flows are estimated based on trade in agricultural and industrial commodities. The global annual average WF in the period 1996-2005 was 9,087 Gm 3 ∕y (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 Gm 3 ∕y (68% green, 13% blue, 19% gray). The WF of the global average consumer was 1,385 m 3 ∕y. The average consumer in the United States has a WF of 2,842 m 3 ∕y, whereas the average citizens in China and India have WFs of 1,071 and 1,089 m 3 ∕y, 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.globalization | sustainable consumption | virtual water trade | water pollution

Impacts Embodied in Global Trade Flows

“…Forty per cent of the national carbon footprint of the UK is exerted abroad (Hertwich and Peters 2009 ) and 75 % of its national water footprint (Hoekstra and Mekonnen 2012 ). The numbers presented in Table 8.1 are the latest available, but there has been a strongly increasing trend for the last few decades.…”

Umwelt und Gesellschaft. Herausforderung für Wissenschaft und Politik

“…Im Folgenden werden für die wichtigsten Sektoren der Wasserwirtschaft in Österreich mögliche Handlungsoptionen in den nächsten Jahrzehnten zusammengefasst (siehe auch ÖWAV, 2015, Blöschl et al, 2011 Bestandesbehandlung und den Produktionszeitraum der Bodenkohlenstoffpool aufgebaut werden kann (Paustian et al, 2016 Wasserimport aus den Herkunftsländern der Produkte dar, der etwa 20 % des Wasserbedarfes beträgt (Hoekstra & Mekonnen, 2012 …”

Improving global environmental management with standard corporate reporting

“…The global water footprint from crop production is 7.4 trillion m 3 /y (95), not including 913 billion m 3 /y for grazing and 46 billion m 3 /y for livestock's direct water footprint (96). Altogether, agricultural production accounts for 70% of water withdrawals (97).…”