Water Depletion: A Global Crisis
Water is being depleted at sites around the world
Intensive groundwater pumping, evaporation, and melting due to rising global temperatures have resulted in a significant shift of freshwater from the continents to the oceans. This poses a serious threat to water availability for a large portion of the world’s population and contributes to rising sea levels.
Jay Famiglietti from Arizona State University, along with his team, utilized gravity measurements from satellites to assess changes in the total amount of water mass stored on the continents. This includes all forms of freshwater, such as rivers, underground aquifers, glaciers, and ice sheets.
Their findings revealed alarming declines in freshwater in various parts of the world between 2002 and 2024. Dry regions are not only becoming drier, as expected due to climate change, but they are also expanding by over 800,000 square kilometers annually, an area equivalent to the size of the UK and France combined.
The researchers identified four “mega-drying” regions where distinct areas of freshwater loss have merged to create extensive drying zones. These regions include northern Canada and Russia, where loss is driven by melting glaciers, permafrost thawing, and reduced snowfall.
In the other two regions, groundwater depletion, primarily from irrigation pumping, is the main cause of water loss. These regions encompass the US Southwest, much of Central America, and a stretch from western Europe and North Africa to northern India and China. Groundwater depletion accounts for 68% of the overall decline in water storage.
This substantial transfer of mass has become a significant contributor to sea level rise. Since 2015, water loss from the continents has led to more sea level rise than meltwater from the Antarctic or Greenland ice sheets, causing the oceans to rise by just under a millimeter per year.
These concerning trends convey a dire message about the impact of climate change. “The continents are drying, freshwater availability is shrinking, and sea level rise is accelerating,” state the researchers in their report.
Manoochehr Shirzaei from Virginia Polytechnic Institute and State University acknowledges that while drying trends in various regions were already known, this research provides a global perspective on the issue. He emphasizes, “We are not creating or destroying water. We are simply redistributing it. However, the redistribution is not heading in the right direction.”
Benjamin Cook from Columbia University in New York suggests the next step is to conduct a detailed analysis to differentiate between the drivers of groundwater depletion. He highlights the need to separate the impact of climate change from the effects of groundwater depletion.
By understanding the implications of water depletion on a global scale, we can take proactive measures to address this critical issue before it escalates further.
