Water problems in Asia’s future?
The scientists then ran an extensive series of repeated projections using varying conditions. In what they call the “Just Growth” scenario, they held climate conditions constant and evaluated the effects of economic and population growth on the water supply. In an alternate “Just Climate” scenario, the scientists held growth constant and evaluated climate-change effects alone. And in a “Climate and Growth” scenario, they studied the impact of rising economic activity, growing populations, and climate change.
Approaching it this way gave the researchers a “unique ability to tease out the human [economic] and environmental” factors leading to water shortages and to assess their relative significance, Schlosser says.
This kind of modeling also allowed the group to assess some of the particular factors that affect the different countries in the region to varying extents.
“For China, it looks like industrial growth [has the greatest impact] as people get wealthier,” says Fant. “In India, population growth has a huge effect. It varies by region.”
The researchers also emphasize that evaluating the future of any area’s water supply is not as simple as adding the effects of economic growth and climate change, and it depends on the networked water supply into and out of that area. The model uses a network of water basins, and as Schlosser notes, “What happens upstream affects downstream basins.” If climate change lowers the amount of rainfall near upstream basins while the population grows everywhere, then basins farther away from the initial water shortage would be affected more acutely.
Future research directions
Other scholars who have examined the work say it makes a valuable contribution to the field.
“They’re looking at a really important issue for the world,” says Channing Arndt, an agricultural economist at the United Nations’ World Institute for Development Economics Research, who thinks that the basic finding of the study “makes sense.”
Arndt also believes that the ambitious scope of the study, and the way it evaluates the effects of climate change as well as economic and population growth, is a worthwhile approach. “Doing it in this integrated way is the right way to go about it,” he adds.
The research team is continuing to work on related projects, including one on the effects of mitigation on water shortages. While those studies are not finished, the researchers say that changing water-use practices can have significant effects.
“We are assessing the extent to which climate mitigation and adaptation practices — such as more efficient irrigation technologies — can reduce the future risk of nations under high water stress,” Schlosser says. “Our preliminary findings indicate strong cases for effective actions and measures to reduce risk.”
The researchers say they will continue to look at ways of fine-tuning their modeling in order to refine their likelihood estimates of significant water shortages in the future.
“The emphasis in this work was to consider the whole range of plausible outcomes,” Schlosser says. “We consider this an important step in our ability to identify the sources of changing risk and large-scale solutions to risk reduction.”
— Read more in Charles Fant et al., “Projections of Water Stress Based on an Ensemble of Socioeconomic Growth and Climate Change Scenarios: A Case Study in Asia,” is being published today in the journal PLOS One (30 March 2016) (doi: org/10.1371/journal.pone.0150633
Reprinted with permission of MIT News
