Water Usage Surpassing Global Supply

Population growth could cause the global demand for water to outpace the world's supply by mid-century if current levels of consumption continue, and not for the first time.

According to a study from Duke University using a delayed-feedback mathematical model that analyzes data to help project future trends, researchers have identified a regularly recurring pattern of global water usage in recent centuries. Historically, periods of increased demand for water, often coinciding with population growth or other major demographic and social changes, were followed by periods of rapid innovation of new water technologies that helped end or ease any shortages. Based on this recurring pattern, the model predicts a similar period of innovation could occur in the coming decades.

Anthony Parolari, a Post-Doctoral Research Associate in Civil and Environmental Engineering, who led the new study, says:

“Researchers in other fields have previously used this model to predict earthquakes and other complex processes, including events like the boom and bust of the stock market during financial crises, but this is the first time it’s been applied to water use. What the model shows us is that there will likely be a new phase of change in the global water supply system by the mid-21st century. This could take the form of a gradual move toward new policies that encourage a sustainable rate of water use, or it could be a technological advancement that provides a new source of water for us to tap into."

Data on global water usage shows we are currently in a period of relatively stagnant growth. Per-capita water usage has been declining since 1980, largely due to improved efficiency measures and heightened public awareness of the importance of conserving earth’s limited supply of freshwater, which has helped offset the impacts of recent population growth. If population growth trends continue, however, water usage will have to decline. Currently, the world’s population is projected to surge to 9.6 billion by 2050, up from an estimated 7 billion today, which will result in a direct impact on population growth, forcing us to find new sources of water supply. 

Water recycling, and finding new and better ways to remove salt from seawater, are among the more likely technological advances that could help alleviate or avoid future water shortages. 

Parolari was inspired to conduct his study by the work of Austrian Physicist and Philosopher Heinz von Foerster, who in 1960 collaborated with students to publish a tongue-in-cheek study in the journal Science, predicting that through feedback between human demographics and technological developments, population growth would overcome any limitation imposed on it by finite resources and become infinite by November 13, 2026, the 115th anniversary of von Foerster’s birthday, in what became known as the Doomsday Equation.

Parolari added:

“Historically, many hypotheses about future population and resource trends have been pessimistic. Von Foerster’s hypothesis poked fun at these projections. But the serious part of his study provided an alternative and exciting view of the future: Humans are creative and resourceful, and when push comes to shove, we find new ways to either increase our supply or use what we have more efficiently. Our model supports this more optimistic outlook. The demand for water will push us to innovate as it has repeatedly done before.”

Parolari and his colleagues published their study this month in the peer-reviewed journal Wiley Interdisciplinary Reviews: Water. His co-authors on the new commentary were Gabriel G. Katul, Theodore S. Coile Professor of Hydrology and Micro-Meteorology at the Nicholas School of the Environment, and Amilcare Porporato, Addy Professor of Civil and Environmental Engineering at the Nicholas School of the Environment and the Pratt School of Engineering.