Auburn University climate researcher foresees water scarcity by the end of 21st century

Published: March 13, 2015
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AUBURN UNIVERSITY – Research by an Auburn University assistant professor implies that more than half of the global land area could experience water scarcity by the end of 21st century.

Shufen "Susan" Pan, of Auburn's International Center for Climate and Global Change Research and the School of Forestry and Wildlife Sciences, found that in low and high climate change scenarios, global warming would result in a large increase of surface evapotranspiration at the end of the 21st century, a measure of the amount of water lost from the land surface.

Pan and her team found that the ratio of evapotranspiration to precipitation would greatly increase across about 60 percent of the global land area. The ratio of evapotranspiration to precipitation is a measure for the potential evaporative demand—in the simplest terms, potential water scarcity.

"Regions like Africa would face the largest increase in evapotranspiration, a problem compounded in this area, for example, where at least 44 percent of the population already lacks access to clean, reliable water sources," Pan said.

Her research, published in Earth's Future, is part of a broader focus on the nexus of interdependency between water, food, energy and changing climate. Pan is interested in the ways that water, food and energy security are interdependent with multiple ways of mutual influence, and how those three factors in turn hinge on climate.

"Both energy and food production depend on readily available water, which requires energy in turn for purification and transport, but is also affected by pollution from both energy and food production," she said.

For Pan, who has a broad interdisciplinary background including ecology, economics and geographic information systems, this research means a lot to her personally. She says that the information available on how many people in the world are already suffering from water and food insecurity is distressing to her, and the indications are that it will only get worse.

"One billion people lack reliable access to safe drinking water, two to three million children die each year from water-related diseases and 171 million children are suffering from chronic malnutrition," she said.

These numbers are not only numbers to Pan, and she speaks passionately about the devastation vulnerable populations could experience when changing climate intensifies already stressed water and food sources. However, she believes pursuing solutions to one problem at a time will prove insufficient.

"These problems must be considered as they relate to each other, or they will prove unmanageable," said Pan, who admits that it's a tough problem.  "Only one person cannot solve this issue."

But what she can do is provide science-based information for mitigation and adaptation related especially to food and water security. Due to the complexity of the issue, she says a holistic approach integrating multiple academic disciplines and linking natural systems to human ones is necessary.

Her principal tool in this research is her computer. Pan uses a complex ecosystem model developed by the International Center for Climate and Global Change Research over the course of 10 years, called the Dynamic Land Ecosystem Model. This model uses terabytes of observed data to model future ecosystem interactions, and is unique, Pan says, in including food crop production, water dynamics, energy flow and three major greenhouse gases in its calculations.

"From both scientific and policy perspectives with regard to climate, it is of critical importance to not only reduce greenhouse gas emissions, but to prepare for water scarcity in the 21st century," Pan said.

Pan's article is available at

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