Aging populations could cut global water demand by 30 per cent

Against a backdrop of water scarcity emerging as one of the most pressing challenges of the 21st century, there’s good news that a subtle demographic shift brings.

New research has suggested that aging of societies, resulting from decreasing birth rates and rising life expectancies as healthcare systems improve, could have a surprisingly large impact on global water demand, potentially reducing water withdrawals by as much as 30 per cent by the middle of this century.

While climate change pushes water resources, both surface and sub-surface, into unprecedented extremes, and droughts and floods intensify, the demand for freshwater is rising with population growth and economic development. The good news is that aging populations are projected to reduce global water withdrawals by 15–31 per cent by 2050, with the effect most pronounced in parts of Asia, a new research study has stated.

Historically, projections of water demand have focused on population size, economic growth and climate change. Few assessments have explicitly considered age structure as a driver of water use. By incorporating demographic aging into their analysis, the researchers show that countries with older populations (such as parts of Europe, Japan and North America) are likely to see slower growth or even declines in water demand, while younger-skewing regions, including much of sub-Saharan Africa, may not experience the same effect, according to Phys.org.

Water demand does not solely depend on how many people are alive but also varies with who those people are. The new study finds a strong statistical relationship between the age structure of a population and how much water it uses overall. By analyzing data from countries around the globe, researchers discovered that as the share of older adults increases, total water use declines.

In numerical terms, a one per cent increase in the proportion of the population aged 65 and over corresponds to an approximate 2.17 per cent decrease in water use, with the strongest effect seen in industry, where withdrawals fall by around 2.6 per cent, compared with smaller declines in domestic (~2.3 per cent) and irrigation (~1.9 per cent) water use.

Older adults typically have lower rates of water-intensive activity than younger people. They may travel less, use fewer resources tied to work and leisure, and consume differently across goods and services that drive water demand.

While the study does not claim aging directly conserves water like a tap being turned off, it shows that demographic change reshapes consumption patterns in ways that can significantly reduce demand across sectors such as household use, agriculture and industry.

According to the researchers’ models, this demographic shift alone could reduce global water withdrawals from rivers, lakes and aquifers by 15–31 per cent by 2050, compared with what it would be if age structures remained static, Phys.org said, quoting the research.

“Little has been known whether intensified global population aging has an independent effect on water use (which corresponds to the global water security). We here use panel analysis to quantitatively find out an obvious declining effect of global population aging (measured by proportion of aged population) on water use (measured by total water withdrawal (TWW)) based on the data of 168 countries in 1987–2018 and then analyze the potential mechanisms leading to the effect”, the authors state.