Population Growth Would Fuel Global Water Shortage

Civil and environmental engineering associate professor Auroop Ganguly in February published findings that population growth, not climate change, tends to have the larger impact on water availability both globally and across multiple regions of the world. Ganguly has developed a computational model to predict future water availability based on both climate- and global population change. The findings are part of a larger research project funded by a five-year, $10 million National Science Foundation grant for understanding climate change with data-driven computational methods.

Source: News @ Northeastern

A cen­tury from now, the world will be a dryer place. Pop­u­la­tion rise will lead to a greater demand for water and cli­mate change will decrease global rain­fall, increase evap­o­ra­tion and lower supply. These changes will have a tan­gible impact on society, from indi­vid­uals hoping to quench their thirst to gov­ern­ments plan­ning national secu­rity strate­gies and inter­na­tional trade routes.

North­eastern Uni­ver­sity civil and envi­ron­mental engi­neering asso­ciate pro­fessor Auroop Gan­guly has devel­oped a com­pu­ta­tional model to pre­dict future water avail­ability based on both cli­mate– and global pop­u­la­tion change.

The find­ings — part of a larger research project funded by a five-​​year, $10 mil­lion National Sci­ence Foun­da­tion grant for under­standing cli­mate change with data-​​driven com­pu­ta­tional methods — were pub­lished in Feb­ruary in the journal Com­puters and Geo­sciences.

Today the world is home to nearly seven bil­lion people, all vying for water from the same global pool. By the middle of the cen­tury, experts pre­dict the pop­u­la­tion to increase to some nine or 10 bil­lion. But moving for­ward, pop­u­la­tion pre­dic­tions are less certain.

From the middle of the cen­tury to the end of the cen­tury, that’s where there are mul­tiple sce­narios,” noted Gan­guly, whose research focuses on cli­mate change, water sus­tain­ability and extreme weather events such as hur­ri­canes and heat waves.

In the “best-​​case” sce­nario, Gan­guly said, the world will become more eco­nom­i­cally equi­table. The income level of devel­oping nations will begin to align with their more-​​developed neighbors.

There’s almost a direct rela­tion of income levels and lifestyles with pop­u­la­tion growth,” said Gan­guly. “At the risk of over-​​generalization, if you are doing better eco­nom­i­cally, you tend to have less chil­dren, other things remaining the same.”

In the best-​​case sto­ry­line, global pop­u­la­tion growth slows down. But in the “worst-​​case” sce­nario, Gan­guly added, the global economy will become less equi­table and pop­u­la­tion growth will speed up.

In a first order assump­tion about the change in the demand for water, one of the major fac­tors is the change in pop­u­la­tion,” said Gan­guly, who also heads Northeastern’s Sus­tain­ability & Data Sci­ences (SDS) Lab.

In the research paper, Gan­guly and his col­leagues Evan Kodra of the SDS Lab,  Karsten Stein­haeuser of the Uni­ver­sity of Min­nesota and Esther Parish of the Oak Ridge National Lab­o­ra­tory, pre­sented a new com­pu­ta­tional and geo­graph­ical infor­ma­tion sci­ence (GIS) model to esti­mate per capita fresh­water avail­ability in 2025, 2050 and 2100. Computer-​​based pre­dic­tions of green­house gas emis­sions over the next cen­tury drove the cli­mate projections.

Regard­less of the inputs, how­ever, the GIS model pro­jected less water avail­ability in all three future decades. The sur­prising new finding is that pop­u­la­tion growth, not cli­mate change, tends to have the larger impact on water avail­ability both glob­ally and across mul­tiple regions of the world.

A related study of the con­ti­nental United States by the same research team found that the worst-​​case cli­mate change sce­nario would increase water stress in five per­cent of the pop­u­la­tion, but that a worst-​​case pop­u­la­tion growth sce­nario would increase water stress in 13 per­cent of the population.

The num­bers seem striking, but Gan­guly views these results as “exem­plary insights” in need of more detailed analysis with a wider scope.

Related Faculty: Auroop R. Ganguly

Related Departments:Civil & Environmental Engineering