Population ageing could reduce global freshwater withdrawals by 15-31% by 2050

Anew study in Water Resources Research has concluded that population ageing - declining birth rates and increasing life expectancy - can markedly reduce future water demand. The authors estimate that demographics alone could reduce global water withdrawals by 15-31 per cent by 2050 (depending on the world scenario).

The authors note that most water demand projections traditionally rely on population, economic growth and climate risks, but rarely consider age structure separately. Meanwhile, analyses of panel data for 168 countries for 1987-2018 showed a strong statistical relationship: the higher the share of the elderly, the lower the total water withdrawal.

In numbers, the effect looks like this: a 1% increase in the share of the population above a certain age is associated, on average, with a drop in total water withdrawal by about 2.17% (coefficient estimate β ≈ -0.0217). The researchers further tested the pattern on spatial (grid) data for 2000-2010, and then projected the contribution of the "ageing factor" to future changes in water use under the SSP1-SSP5 scenarios.

The paper emphasises: ageing in itself does not mean 'saving water' as if someone had closed the tap. Rather, consumption patterns and the structure of the economy are changing: on average, older people are less likely to engage in water-intensive activities, consume goods and services differently, and this affects demand from households, industry and agriculture.

However, the study does not dismiss the severity of the water problem: globally, water stress and scarcity remain widespread, and climate change is increasing the instability of the water cycle. The authors suggest using the "demographic lens" as another planning tool to better estimate future stresses on water infrastructure and to avoid misjudging investments in reservoirs, treatment plants and distribution systems.