Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Climate change puts forty percent more people at risk of absolute water scarcity

Water scarcity impacts people’s lives in many countries already today. Future population growth will increase the demand for freshwater even further.

Yet in addition to this, on the supply side, water resources will be affected by projected changes in rainfall and evaporation. Climate change due to unabated greenhouse-gas emissions within our century is likely to put 40 percent more people at risk of absolute water scarcity than would be without climate change, a new study shows by using an unprecedented number of impact models.

The analysis is to be published in a special issue of the Proceedings of the National Academy of Sciences that assembles first results of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), a unique community-driven effort to bring research on climate change impacts to a new level.

“The steepest increase of global water scarcity might happen between 2 and 3 degrees global warming above pre-industrial levels, and this is something to be experienced within the next few decades unless emissions get cut soon,” says lead-author Jacob Schewe of the Potsdam Institute for Climate Impact Research. “It is well-known that water scarcity increases, but our study is the first to quantify the relative share that climate change has in that, compared to – and adding to – the increase that is simply due to population growth.”

Today, between one and two people out of a hundred live in countries with absolute water scarcity. Population growth and climate change combined would increase this to about ten in a hundred at roughly 3 degrees global warming. Absolute water scarcity is defined as less than 500 cubic meters available per year and person – a level requiring extremely efficient water use techniques and management in order to be sufficient, which in many countries are not in place. For a comparison, the global average water consumption per person and year is roughly 1200 cubic meters, and significantly more in many industrialized countries.

As climate change is not uniform across the world, the regional differences of its impacts on water availability are huge. For example, the Mediterranean, Middle East, the southern USA, and southern China will very probably see a pronounced decrease of available water, according to the study. Southern India, western China and parts of Eastern Africa might see substantial increases.

“Water scarcity is a major threat for human development, as for instance food security in many regions depends on irrigation – agriculture is the main water user worldwide,” says co-author Qiuhong Tang of the Chinese Academy of Sciences. “Still, an increase of precipitation is also challenging – the additional water may cause water logging, flooding, and malfunctioning or failure of water-related infrastructure. So the overall risks are growing.” Moreover, many industrial production processes require large amounts of water, so a lack thereof in some regions hampers economical development.

This study is based on a comprehensive set of eleven global hydrological models, forced by five global climate models – a simulation ensemble of unprecedented size which was produced in collaboration by many research groups from around the world. Hence, the findings synthesize the current knowledge about climate change impacts on water availability. The cooperative ISI-MIP process systematically compares the results of the various computer simulations to see where they agree and where they don’t. The results quoted above represent the multi-model average. So some of the models indicated even greater increases of water scarcity.

“The multi-model assessment is unique in that it gives us a good measure of uncertainties in future impacts of climate change – which in turn allows us to understand which findings are most robust,” says co-author Pavel Kabat of the International Institute for Applied Systems Analysis (IIASA). “From a risk management perspective, it becomes very clear that, if human-made climate change continues, we are putting at risk the very basis of life for millions of people, even according to the more optimistic scenarios and models.”

However, he added, the job is far from being done. “We need to do additional research on how the water requirement portfolio will develop in the future in different sectors like agriculture, industry, and energy – and how, in addition to reducing greenhouse-gas emissions, the technological developments in the water sector may help alleviating water scarcity.”

Article: Schewe, J., Heinke, J., Gerten, D., Haddeland, I., Arnell, N.W., Clarke, D.B., Dankers, R., Eisner, S., Fekete, B.M., Colón-González, F.J., Gosling, S.M., Kim, H., Liu, X., Masaki, Y., Portmann, F.T., Satoh, Y., Stacke, T., Tang, Q., Wada, Y., Wisser, D., Albrecht, T., Frieler, K., Piontek, F., Warszawski, L., Kabat, P. (2013): Multi-model assessment of water scarcity under climate change. Proceedings of the National Academy of Sciences (early online edition) [DOI:10.1073/pnas.1222460110]

Along with this article, further ISI-MIP results are published online by PNAS:

Dankers, R., et al. (2013): First look at changes in flood hazard in the Inter-Sectoral Impact Model Intercomparison Project ensemble. Proceedings of the National Academy of Sciences (early online edition)

Elliott, J., et al (2013): Constraints and potentials of future irrigation water availability on agricultural production under climate change. Proceedings of the National Academy of Sciences (early online edition)

Friend, A. D., et al. (2013): Carbon residence time dominates uncertainty in terrestrial vegetation responses to future climate and atmospheric CO2. Proceedings of the National Academy of Sciences (early online edition)

Haddeland I., et al. (2013): Global water resources affected by human interventions and climate change. Proceedings of the National Academy of Sciences (early online edition)

Nelson, G. C., et al. (2013): Climate change effects on agriculture: Economic responses to biophysical shocks. Proceedings of the National Academy of Sciences (early online edition)

Piontek, F., et al. (2013): Multisectoral climate impact hotspots in a warming world. Proceedings of the National Academy of Sciences (early online edition) [DOI:10.1073/pnas.1222471110]

Prudhomme, C., et al. (2013): Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment. Proceedings of the National Academy of Sciences (early online edition)

Rosenzweig, C., et al. (2013): Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison. Proceedings of the National Academy of Sciences (early online edition)

Schellnhuber, H.J., et al (2013): The Elephant, the Blind, and the ISI-MIP. Proceedings of the National Academy of Sciences (early online edition)

Warszawski, L., et al. (2013): The Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP): Project framework. Proceedings of the National Academy of Sciences (early online edition)

For further information please contact:
PIK press office
Phone: +49 331 288 25 07
Twitter: @PIK_Climate
Weitere Informationen:

Jonas Viering | PIK Pressestelle
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

3-D-printed structures shrink when heated

26.10.2016 | Materials Sciences

Indian roadside refuse fires produce toxic rainbow

26.10.2016 | Health and Medicine

First results of NSTX-U research operations

26.10.2016 | Physics and Astronomy

More VideoLinks >>>