Media release

From: Springer Nature

Rapid groundwater declines in many aquifers globally (N&V) *IMAGES & VIDEO*   

Groundwater stored in aquifers across the globe may face declines of over 0.5 metres per year in the 21st century, an analysis of around 170,000 monitoring wells published in Nature reveals. These aquifers, however, can recover following policy changes and improved aquifer management, amongst other initiatives.

Aquifers are a crucial source of freshwater for farms, homes, industries, and cities across the world. However, aquifers across the globe may be becoming less accessible owing to changes in Earth’s climate as well as excessive water usage, threatening economies and ecosystems. While satellite maps of groundwater provide some insight into storage trends, in situ measurements from monitoring wells and analysis of those wells at a global scale can offer scientists and governments a more comprehensive look at aquifer depletion trends.

Scott Jasechko and colleagues analysed approximately 170,000 groundwater monitoring wells in over 40 countries to project aquifer trends into the remainder of the 21st century. In defining 1,693 aquifer systems across the planet, the researchers found that 36% of aquifers were declining by 0.1 metres per year, while 12% were declining rapidly at rates that exceeded 0.5 metres per year. In comparing these findings to groundwater depletion data from 1980 to 2000, the team found that 30% of the studied aquifers faced accelerated depletion in the 21st century, especially in dry regions.

The researchers also found that 6% of the aquifers in the data rose by 0.1 metres per year, while 1% rose at a rate of 0.5 metres per year. The authors propose that this growth trend could be a result of reductions in groundwater consumption, implementation of groundwater consumption policies, surface water transfers, changes in land cover, and managed recharge projects.

Jasechko and colleagues note that the sample analysed in this research is not a randomized sample of global groundwater wells, and that combining different sets of in situ measurements could provide even clearer trends over a wider area.