Groundwater quality in the face of global warming

The global warming that the Earth is suffering due to the increasing concentration of greenhouse gases in the atmosphere limits the amount of heat that the Earth can radiate into space. The oceans absorb a substantial fraction of this heat, but soil and groundwater also act as heat sinks. However, very little was known until now about the effects that warming of the Earth’s surface has and will have on groundwater.

To answer the questions, a team including Susanne A. Benz, Kathrin Menberg and Philipp Blum, all three from the Karlsruhe Institute of Technology (KIT) in Germany, ran computer simulations based on the SSP 2-4.5 climate scenarios. and SSP 5-8.5. These scenarios reflect different paths of socioeconomic development and different trends in the atmospheric concentration of greenhouse gases generated by human activities in the future. SSP 2-4.5 is in the middle range of possible future greenhouse gas concentration trends. The SSP 5-8.5 is on the high end.

Working with maps showing global groundwater temperatures at various depths below the Earth’s surface, and forecasting changes in global temperatures through 2100, researchers have concluded that increased rates of warming of the world’s groundwater can be expected in places with a shallow water table and/or high atmospheric warming.

The study indicates that by 2100, groundwater temperature will increase by 2.1 degrees Celsius in the SSP 2-4.5 scenario and 3.5 degrees Celsius in the SSP 5-8.5 scenario. There are already some 30 million people living in regions where groundwater is warmer than stipulated in the strictest drinking water guidelines. That means the untreated water may not be safe to drink. For example, it may need to be boiled first. Drinking water is also heated in pipes by heat from underground. Depending on the scenario, up to several hundred million people could be affected by 2100.

The new study shows that excessive warming of groundwater could affect millions of people by 2100. (Photo: Susanne Benz / KIT)

According to the study, the number of people affected by the year 2100 would be 77 million to 188 million people for the SSP 2-4.5 scenario and 59 million to 588 million for the SSP 5-8.5 scenario. The wide ranges are due to spatial variations in climate change and demographic trends.

The study is titled “Global groundwater warming due to climate change.” And it has been published in the academic journal Nature Geoscience. (Fountain: NCYT by Amazings)