A groundbreaking study published in the Journal of Geophysical Research: Solid Earth has revealed that large portions of South Africa—and by extension, a section of the African continent—are undergoing measurable land uplift. For years, geoscientists assumed this vertical movement was caused by mantle plumes pushing up from deep within the Earth. But recent findings point to a far more surface-level culprit: drought and the disappearance of water from soil, aquifers, and reservoirs.
Ground Movement Tracks with South Africa’s Drying Landscape
The research team, led by geodesists at the University of Bonn, used high-precision GPS stations scattered across South Africa to analyze elevation changes from 2012 to 2020. They discovered that the continent’s surface has risen by an average of 6 millimeters per year, with some regions lifting as much as 10 millimeters during particularly intense drought seasons.
The turning point in the investigation came when elevation data was compared with the timeline of South Africa’s infamous “Day Zero” drought, when water levels in Cape Town nearly reached municipal shutdown levels. “We started to think there should be a link between this pattern and water loss,” said Makan Karegar, lead author of the study. His team found that the timing of the uplift aligned closely with periods of severe water depletion.
As water vanishes, so does its gravitational pressure on the crust. This removal of weight allows the Earth’s surface to elastically rebound, a process similar to how memory foam regains its shape once compressed weight is removed.
Uplift Wasn’t Local — It Was Nationwide
What surprised researchers wasn’t just the elevation increase, but how widespread it was. While it was expected that land closest to major cities and reservoirs would show signs of uplift, the results showed that even remote rural areas experienced vertical movement.
“The biggest surprise for us was that we saw an uplift over most parts of South Africa,” noted Christian Mielke, coauthor of the study. “We were expecting that this would probably just affect regions close to cities,” he told Live Science. Yet the data revealed consistent patterns of uplift throughout much of the country, indicating that water loss across the landscape—not just near urban infrastructure—was contributing to the elevation gain.
This suggests that the water table and subsurface moisture reserves across the continent play a much larger role in geophysical behavior than previously assumed.
GPS Networks as Tools for Tracking Climate Stress
The implications of this discovery go beyond geology. The use of GPS data to detect such small but significant land movements could evolve into an effective method of drought detection. While traditional climate models use satellite imagery and precipitation tracking, GPS elevation data offers a real-time, ground-level indicator of water stress.
In countries with denser GPS infrastructure, such as the United States, this approach could become a frontline tool in water resource management and disaster preparedness. Karegar emphasized this point in his interview: in regions where GPS stations are closely spaced, it would be possible to monitor changes with much greater spatial precision.
This method also provides an independent means of verifying climate models, helping to confirm when and where subsurface water depletion is happening — before other systems register the change.