Global threats to human water security and river biodiversity

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Protecting the world’s freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the world’s population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity.

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Change history

  • Corrected online 30 September 2010

    In the PDF version of this Article, the present address for P. B. McIntyre was truncated; this had now been corrected


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We thank A. DeSherbinin, L. Poff, C. Revenga, J. Melillo and O. Young for comments on the manuscript; D. Allan, R. Abell, J. Bogardi, M. Meybeck, W. Wollheim, R. F. Wright, D. Boswell, R. Lacey, N. Schneider and D. Vörösmarty for advice; and D. Dube and B. Fekete for technical support. Grant support for database and tool development was from NASA Inter-Disciplinary Science Program Grant NNX07AF28G, with additional support from the NSF Division of Earth Sciences (Hydrologic Sciences Program Award #0854957) and Global Environment Facility (UPI 00345306). P.B.M. was supported by a D.H. Smith Fellowship. Financial and logistical support for expert group meetings and communications was from the Global Water System Project (Bonn), DIVERSITAS-freshwaterBIODIVERSITY (Paris), NSF BestNet, and Australian Agency for International Development (AusAID) through the Australian Water Research Facility. Conference facilities were provided by the Swiss Federal Institute of Science & Technology (Eawag) and The City College of New York/CUNY.

Author information

Author notes

    • C. J. Vörösmarty
    •  & P. B. McIntyre

    These authors contributed equally to this work.

    • P. B. McIntyre

    Present address: Center for Limnology, University of Wisconsin, Madison, Wisconsin 53706, USA.


  1. The Environmental CrossRoads Initiative, City University of New York, The City College of New York, New York, New York 10035, USA

    • C. J. Vörösmarty
    •  & P. Green
  2. School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan 48109, USA

    • P. B. McIntyre
  3. Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, and Institute of Integrative Biology (IBZ), ETH Zurich, 8600 Dübendorf, Switzerland and Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany

    • M. O. Gessner
  4. Division of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China

    • D. Dudgeon
  5. Water Systems Analysis Group, University of New Hampshire, Durham, New Hampshire 03824, USA

    • A. Prusevich
    •  & S. Glidden
  6. Australian Rivers Institute, Griffith University, Nathan, Queensland 4111, Australia

    • S. E. Bunn
  7. School of Environmental Science and Management, Southern Cross University, New South Wales 2480, Australia

    • C. A. Sullivan
  8. School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA

    • C. Reidy Liermann
  9. Centre of Excellence in Natural Resource Management, The University of Western Australia, Albany 6330, Australia

    • P. M. Davies


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All authors contributed to project conceptualization during workshops led by C.J.V. C.J.V. designed the global analysis, and P.B.M., A.P., P.G. and M.O.G. designed and implemented the analytical approach with essential input from S.E.B., D.D., C.A.S., P.M.D. and C.R.L. A.P., P.G. and S.G. developed the database and mapping tools. Several authors led a separate component of data set development and all provided quality assurance. C.J.V., P.B.M. and M.O.G. wrote the manuscript with input from all authors.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to C. J. Vörösmarty.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains Supplementary Methods, Supplementary Tables 1-3, Supplementary Figures 1- 12 with legends, Supplementary Discussion, and additional references.