Yoshihide Wada


Reducing water scarcity possible by 2050: Linking global assessments to policy dimensions – PDF

Author: Yoshihide Wada

NASA Goddard Institute for Space Studies, New York, USA
Center for Climate Systems Research, Columbia University, New York, USA
Department of Physical Geography, Utrecht University, Utrecht, The Netherlands 

Water scarcity is not a problem just for the developing world. In California, USA, legislators are currently proposing a $7.5 billion emergency water plan to their voters; and US federal officials last year warned residents of Arizona and Nevada that they could face cuts in Colorado River water deliveries in 2016.

Irrigation techniques, industrial, and residential habits, combined with climate change, lie at the root of the problem. But despite what appears to be an insurmountable problem, it is possible to turn the situation around and significantly reduce water scarcity in over next 35 years.

We identify strategies in six key areas that we believe can be combined in different ways in different parts of the world in order to effectively reduce water stress. Water stress occurs in an area where more than 40% of the water from rivers is unavailable because it is already being used – a situation that currently affects about a third of the global population, and may affect as many as half the people in the world by the end of the century if the current pattern of water use continues).

We separate six key strategy areas for reducing water stress into “hard path” measures, involving building more reservoirs and increasing desalination efforts of sea water, and “soft path” measures that focus on reducing water demand rather than increasing water supply, thanks to community-scale efforts and decision-making, combining efficient technology and environmental protection. While there are some economic, cultural, and social factors that may make certain soft-path measures difficult (such as population control), soft-path measures offer the more realistic path forward in terms of reducing water stress by 2050.


Dr. Yoshihide Wada is a research scientist at the NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, USA. He also works for the Department of Physical Geography, Faculty of Geosciences, Utrecht University, the Netherlands and IIASA. He obtained his PhD degree with distinction (Cum Laude) at Utrecht University in October 2013. His completed PhD projects include estimating global water use and water availability by using the global hydrological and water resources model PCR-GLOBWB. His work also includes estimating and projecting global water scarcity, and assessing the sustainability of global groundwater resources. His current research projects include a global assessment of the sustainability of future food production under socioeconomic and climate change, and water scarcity. He is one of the recipients of the Horton (Hydrology) Research Grant by the American Geophysical Union. He has participated in a number of international projects including the European Global Water Scarcity Information Service Project, Inter-Sectoral Impact Model Intercomparison Project and Water Futures and Solutions. He has also participated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change as a contributing author (Working Group I). Yoshihide Wada (co)authored about 60 publications, 40 of which appeared in international, peer-reviewed journals.


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