Earth's Freshwater Supply Declining Rapidly: A Warning of Prolonged Droughts Ahead

An international team of scientists has found that Earth’s freshwater supply started to decline sharply in May 2014 and has stayed low ever since.

The study, published in Surveys in Geophysics, suggests this could mean Earth’s continents are entering a prolonged dry period.

From 2015 to 2023, satellite data showed that the amount of freshwater stored on land—including lakes, rivers, and groundwater—was 290 cubic miles (1,200 cubic kilometers) lower than the average from 2002 to 2014. This is more than twice the volume of Lake Erie.

The study explains that during droughts, cities and farms rely more on groundwater, which leads to a cycle of depleting water supplies.

Freshwater reserves get low, rainfall and snow fail to replenish them, and more groundwater is extracted, worsening the problem.

These water shortages can put pressure on communities and agriculture, increasing the risk of famine, conflict, poverty, and disease. A 2024 UN report on water stress highlights these risks.

The researchers used data from the GRACE satellites, which monitor changes in Earth's gravity to track water levels.

The first GRACE satellites operated from 2002 to 2017, and the GRACE-FO satellites, launched in 2018, continue to monitor freshwater.

The decline began with a severe drought in Brazil and was followed by droughts across many parts of the world, including South America, North America, Europe, and Africa.

These droughts were linked to unusually warm ocean temperatures in the tropical Pacific, which caused a major El Niño event from 2014 to 2016. Despite the end of El Niño, freshwater levels did not recover. In fact, 13 of the 30 most intense droughts recorded by GRACE satellites happened after 2015.

Experts believe climate change may be contributing to the ongoing loss of freshwater.

As the planet warms, the atmosphere holds more water vapor, leading to extreme weather events, including heavy rainfall. However, long dry spells between these rainstorms prevent the soil from absorbing water, making it harder to replenish groundwater. When heavy rain does occur, much of the water runs off rather than soaking into the ground.

Although it is still uncertain how much climate change is affecting freshwater levels, the scientists suggest that rising temperatures could be a factor.

The nine warmest years on record have coincided with the drop in freshwater, which could be a sign of things to come.

It is unclear whether global freshwater levels will recover or continue to decline.