A new study warns that groundwater sources, crucial for nearly one-fourth of the global population lacking access to surface water, could become undrinkable for hundreds of millions of people by the end of this century due to rising temperatures exacerbated by climate change.
Published by an international team of researchers, the study utilizes a global-scale model to forecast the effects of increasing temperatures on groundwater across the world under various warming scenarios. According to their findings, approximately 590 million people could face severe challenges accessing safe drinking water from groundwater sources by the year 2100.
Hydrologist Dylan Irvine from Charles Darwin University in Australia emphasized the overlooked impact of climate change on groundwater, stating, “A lot of focus on climate change has rightfully been to do with weather events and water availability. But we do need to think more broadly about the impact that climate change will have on groundwater.”
Groundwater, stored in porous rock layers beneath the Earth’s surface, is susceptible to temperature changes that can render it toxic and unfit for human consumption. As temperatures rise, groundwater can become contaminated with dissolved minerals, pollutants, and pathogens. Even a slight increase in temperature can reduce oxygen levels, promote bacterial growth, and facilitate the leaching of heavy metals such as manganese and arsenic into the water supply.
Susanne Benz, a geoscientist at the Karlsruhe Institute of Technology in Germany and lead author of the study, highlighted current concerns, noting, “Already, there are approximately 30 million people living in regions where groundwater temperatures exceed the strictest drinking water guidelines. This means that water may require treatment, such as boiling, before consumption.”
The study underscores that the warming of groundwater not only affects direct consumption but also disrupts water distribution systems. Warmer groundwater can alter the chemical composition and dynamics of surface reservoirs, potentially compromising water safety even where surface water is available.
Under the study’s projections based on shared socioeconomic pathways, the number of people at risk could double by 2100, with an estimated 188 million individuals living in regions where groundwater fails to meet stringent drinking water standards without treatment.
