Studies reveal the mechanisms behind tumor metastasis and how to stymie it. But primary tumors still get the lion’s share of researchers’ attention.
Image courtesy of Science Source/Phanie.
New Research In
Physical Sciences
Featured Portals
Articles by Topic
Biological Sciences
Featured Portals
Articles by Topic
Edited by Peter H. Gleick, Pacific Institute for Studies in Development, Environment, and Security, Oakland, CA, and approved December 21, 2011 (received for review June 20, 2011)
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 Gm3/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 Gm3/y (68% green, 13% blue, 19% gray). The WF of the global average consumer was 1,385 m3/y. The average consumer in the United States has a WF of 2,842 m3/y, whereas the average citizens in China and India have WFs of 1,071 and 1,089 m3/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.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: a.y.hoekstra{at}utwente.nl.
Author contributions: A.Y.H. and M.M.M. designed research, performed research, analyzed data, and wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1109936109/-/DCSupplemental.
Freely available online through the PNAS open access option.
The water footprint of humanity
More Articles of This Classification
Physical Sciences
Environmental Sciences
Related Content
Cited by...
- Meat consumption, health, and the environment
- Alternative cereals can improve water use and nutrient supply in India
- Water management and sustainability of water resources
- Editorial: Current water challenges require holistic and global solutions
- Climate change and water management in the biblical city of Dan
- Opportunities for saving and reallocating agricultural water to alleviate water scarcity
- Flexibility and adaptability: essential elements of the WRRF of the future
- Four billion people facing severe water scarcity
- Local flow regulation and irrigation raise global human water consumption and footprint
- Global impacts of energy demand on the freshwater resources of nations
- Assessing the environmental impact of the water footprint in Beijing, China
- Fresh water goes global
- Improving global environmental management with standard corporate reporting
- Systems integration for global sustainability
- What Current Literature Tells Us about Sustainable Diets: Emerging Research Linking Dietary Patterns, Environmental Sustainability, and Economics
- A mid-term analysis of progress toward international biodiversity targets
- Humanity's unsustainable environmental footprint
- Focus on Water
- Green Water and Global Food Security
- Root hydrotropism: An update
- Reply to Ridoutt and Huang: From water footprint assessment to policy
- Environmental relevance--the key to understanding water footprints
Similar Articles
You May Also be Interested in
Both social and engineering factors must be further explored and scrutinized across the globe—as should notions of justice related to flooding impacts and responses.
Image courtesy of Shutterstock.com/Ekaterina Pokrovsky.
Blair Hedges discusses the state of Haiti's remaining forests and the consequences to biodiversity.
A study uncovers genetic evidence of early colonization of Jamaica by primates and suggests that adaptation can shape species morphology in novel environments, even when species come from morphologically conservative families.
Image courtesy of Lorraine Meeker (American Museum of Natural History, New York).
Researchers report that some moth species use sound absorbing-scales to avoid detection by bats and suggest that the findings could aid the design of biologically inspired sound absorbers for an array of applications, including noise mitigation and building acoustics.
Image courtesy of Thomas R. Neil.
