Multimodel assessment of water scarcity under climate change

Jacob Schewe, Jens Heinke, Dieter Gerten, Ingjerd Haddeland, Nigel W Arnell, Douglas B Clark, Rutger Dankers, Stephanie Eisner, Balázs M Fekete, Felipe J Colón-González, Simon N Gosling, Hyungjun Kim, Xingcai Liu, Yoshimitsu Masaki, Felix T Portman, Yusuke Satoh, Tobias Stacke, Qiuhong Tang, Yoshihide Wada, Dominik WisserTorsten Albrecht, Katja Frieler, Franziska Piontek, Lila Warszawski, Pavel Kabat

Research output: Contribution to journalArticlepeer-review

1261 Citations (Scopus)


Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. Here we use a large ensemble of global hydrological models (GHMs) forced by five global climate models and the latest greenhouse-gas concentration scenarios (Representative Concentration Pathways) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that a global warming of 2 °C above present (approximately 2.7 °C above preindustrial) will confront an additional approximate 15% of the global population with a severe decrease in water resources and will increase the number of people living under absolute water scarcity (<500 m3 per capita per year) by another 40% (according to some models, more than 100%) compared with the effect of population growth alone. For some indicators of moderate impacts, the steepest increase is seen between the present day and 2 °C, whereas indicators of very severe impacts increase unabated beyond 2 °C. At the same time, the study highlights large uncertainties associated with these estimates, with both global climate models and GHMs contributing to the spread. GHM uncertainty is particularly dominant in many regions affected by declining water resources, suggesting a high potential for improved water resource projections through hydrological model development.
Original languageEnglish
Article number9
Pages (from-to)3245-3250
JournalProceedings of the National Academy of Sciences of the United States of America (PNAS)
Issue number9
Early online date16 Dec 2013
Publication statusPublished - 4 Mar 2014


  • climate impacts
  • hydrological modelling
  • inter-sectoral impact model intercomparison project

Cite this