Global impacts of energy demand on the freshwater resources of nations
- aCentre for Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom;
- bSustainability Research Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom;
- cCenter for Environmental Systems Research, University of Kassel, 34109 Kassel, Germany;
- dDepartment of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, United Kingdom;
- eUnited Nations Environment Programme World Conservation Monitoring Centre, Cambridge CB3 0DL, United Kingdom;
- fDepartment of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom;
- gDepartment of Earth Science and Engineering, Imperial College, London SW7 2AZ, United Kingdom;
- hSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
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Edited by Dieter Gerten, Potsdam Institute for Climate Impact Research, Potsdam, Germany, and accepted by the Editorial Board September 18, 2015 (received for review April 21, 2015)

Significance
Understanding the role of international trade in driving pressures on freshwater resources is key to meeting challenges at the water–energy nexus. A coupled trade and hydrological model is used to examine pressures on freshwater resources associated with energy production across the global economy. While the electric and gas sectors induce freshwater consumption predominantly within countries where demand originates (91% and 81%, respectively), the petroleum sector exhibits a high international footprint (56%). Critical geographic areas and economic sectors are identified, providing focus for resource-management actions to ensure energy and freshwater security. Our analysis demonstrates the importance of broadening the discourse on energy policy to address issues including freshwater scarcity, the role of international trade, and wider environmental and societal considerations.
Abstract
The growing geographic disconnect between consumption of goods, the extraction and processing of resources, and the environmental impacts associated with production activities makes it crucial to factor global trade into sustainability assessments. Using an empirically validated environmentally extended global trade model, we examine the relationship between two key resources underpinning economies and human well-being—energy and freshwater. A comparison of three energy sectors (petroleum, gas, and electricity) reveals that freshwater consumption associated with gas and electricity production is largely confined within the territorial boundaries where demand originates. This finding contrasts with petroleum, which exhibits a varying ratio of territorial to international freshwater consumption, depending on the origin of demand. For example, although the United States and China have similar demand associated with the petroleum sector, international freshwater consumption is three times higher for the former than the latter. Based on mapping patterns of freshwater consumption associated with energy sectors at subnational scales, our analysis also reveals concordance between pressure on freshwater resources associated with energy production and freshwater scarcity in a number of river basins globally. These energy-driven pressures on freshwater resources in areas distant from the origin of energy demand complicate the design of policy to ensure security of fresh water and energy supply. Although much of the debate around energy is focused on greenhouse gas emissions, our findings highlight the need to consider the full range of consequences of energy production when designing policy.
Footnotes
- ↵1To whom correspondence should be addressed. Email: r.a.holland{at}soton.ac.uk.
Author contributions: R.A.H., K.A.S., G.B., R.M.E., V.K., A.M., J.P.W.S., G.T., J.B., and F.E. designed research; R.A.H. and K.A.S. performed research; R.A.H., K.A.S., M.F., and E.F. analyzed data; and R.A.H., K.A.S., M.F., G.B., R.M.E., E.F., V.K., A.M., J.P.W.S., G.T., J.B., and F.E. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. D.G. is a guest editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1507701112/-/DCSupplemental.
Freely available online through the PNAS open access option.