The ill effects of global warming have now started to reach the groundwater as temperatures are expected to rise by 2-3.5 degrees by the end of this century, which not only potentially compromises the quality of water and its safety, but also risks groundwater biodiversity and ecosystems dependent on this natural resource.
A recent study published in Nature Geoscience has found that the highest warming rates will be visible in Central Russia, Northern China, parts of North America and the Amazon rainforest in South America.
A team of international researchers at the Karlsruhe Institute of Technology in Germany has found the results through the "world's first global groundwater temperature model,” emphasizing the urgent need to address the impacts of climate change on groundwater.
The researchers used data on heat transfer in water to model current groundwater temperatures and project changes from 2000 to 2100 globally.
The results have indicated that “by 2100, between 77 million and 188 million people are projected to live in areas where groundwater exceeds the highest threshold for drinking water temperatures set by any country.”
According to the World Health Organization, only 18 of 125 countries have temperature guidelines for drinking water.
These temperature guidelines, which are often aesthetic, range from 15 °C to 34 °C, with a median of 25 °C, the study said.
The lack of standardized regulations presses the need for global action to address the implications of groundwater warming.
Warmer groundwater also poses a risk of disease-causing microbial growth, including drinking water quality which aggravates the problem of access to clean drinking water.
According to the researchers, while much of the climate change discourse focuses on weather events and water availability, the issue of how rising temperatures affect groundwater should also be focused on.
"Rivers rely on groundwater to keep flowing during dry times. Warm waters hold less dissolved oxygen," said study co-author Gabriel Rau from the University of Newcastle, UK.
He further explained that groundwater warming could have severe consequences on aquatic life, as "rivers rely on groundwater to keep flowing during dry times. Warm waters hold less dissolved oxygen.”
The study serves an important landmark in highlighting the importance of integrating the conservation of groundwater into the broader climate change mitigation and adaptation strategies.
