The world’s groundwater may become undrinkable within a few decades.
By 2100, over 75 million people are at risk of living in areas where groundwater is undrinkable due to excessive heat, according to a new study by the Karlsruhe Institute of Technology (KIT) in Germany.
Groundwater temperatures are projected to rise by 3.5 degrees Celsius by the end of this century, surpassing the maximum limits set for drinking water in any country.
Groundwater in many parts of the world is expected to rise by about 3.5 degrees Celsius.
Groundwater is vital for life, yet we know very little about how climate change affects this resource. As temperatures rise, groundwater acts as a heat sink, absorbing excess heat caused by global warming.
To gain further insight into this issue, the research team at KIT modeled the expected changes in global groundwater temperatures until 2100.
The team calculated based on two climate scenarios, SSP 2-4.5 and SSP 5-8.5, which reflect different socio-economic development pathways and future greenhouse gas concentrations, determining that groundwater temperatures could rise by 2.1 degrees Celsius or 3.5 degrees Celsius, depending on the scenario.
According to the research team, some regions with shallow groundwater or high air temperatures will experience more pronounced increases in groundwater temperatures. This also implies that for millions of people worldwide, groundwater will no longer be safe to drink, as reported by IFLScience on July 8.
Currently, about 30 million people live in areas where groundwater exceeds safe temperature thresholds. This means the water is unsafe for drinking unless boiled. Drinking water in pipes will also be warmer due to heat from the ground.
“Depending on the scenario, hundreds of millions of people could be affected by 2100,” said Dr. Susanne Benz, lead author of the study and a researcher at KIT. Specifically, around 77 to 188 million people may be affected in the SSP 2-4.5 scenario and approximately 59 to 588 million people in the SSP 5-8.5 scenario.
“Our research highlights the importance of taking action to protect groundwater resources and finding long-term solutions to mitigate the negative impacts of climate change on this vital resource,” Dr. Benz concluded.
The study is published in the journal Nature Geoscience.
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Why is warming groundwater becoming undrinkable? The temperature of groundwater affects biogeochemical cycles, impacting water quality. For example, under certain conditions, rising groundwater temperatures can lead to increased concentrations of harmful substances such as arsenic and manganese, which can affect human health, especially when groundwater is used for drinking. Increased groundwater temperatures may also facilitate the growth of pathogens such as Legionella spp, affecting ecosystems, biodiversity, and the carbon and nutrient cycles. |
