Study Finds South Africa’s Land Rising Due to Drought and Water Loss

A study reveals that South Africa’s land is rising due to drought, with an average uplift of 6 millimeters between 2012-2020. Utilizing GPS data, researchers identified correlations between water loss and land movement. The findings suggest a significant link between drought patterns and geological changes, emphasizing the need for effective water management.

Recent findings reveal that the land beneath South Africa is rising due to drought and water loss, according to a new GPS-based study. Between 2012 and 2020, the region experienced an average uplift of approximately 6 millimeters (or 0.2 inches), indicating a significant geological response to changing water levels. The study utilized advanced GPS technology to analyze land movement and its correlation with seasonal drought patterns, shedding light on the ongoing environmental challenges the country faces.

Interestingly, scientists have been aware of this uplift phenomenon for over ten years, but the reasons behind it remained uncertain. Earlier studies suggested a connection with a hot mantle plume exerting pressure from below. However, Makan Karegar, a geodesist at the University of Bonn, noticed something striking: the uplifts seemed to follow drought periods. This discovery was particularly highlighted during the severe “Day Zero” drought that threatened Cape Town between 2015 and 2018. Karegar commented, “We started to think there should be a link between this pattern and water loss.”

To delve deeper into this connection, the research team collected extensive GPS data from permanent monitoring stations across the country. These stations measure small changes in elevation with remarkable precision. The study, published on April 9 in the Journal of Geophysical Research: Solid Earth, proposed a model that links land uplift to shifts in water storage, offering critical insights into the geophysical impacts of prolonged drought.

Diminishing water resources — including surface reservoirs, soil, and groundwater — appeared to prompt the land’s rise, similar to how a memory foam mattress rebounds after weight is released. The study noted some regional variability in the uplift, with certain areas near drained water reservoirs rising by as much as 10 millimeters (0.4 inches), but overall, the trend indicates a widespread response across South Africa.

Christian Mielke, a co-author and fellow geodesist, remarked, “The biggest surprise for us was that we saw an uplift over most parts of South Africa. We were expecting that this would probably just affect regions close to cities,” suggesting that even remote areas are impacted.

The researchers then validated their model by cross-referencing GPS data with established predictions of water loss derived from satellite data and climate observations. They found a strong correlation, reinforcing the idea that water loss is a primary factor influencing land dynamics. While the potential impact of the mantle plume is not entirely dismissed, the evidence points toward drought as a significant driver of uplift.

This uplift may not be permanent, however. Karegar pointed out that the land could sink again with increased rainfall and refilled reservoirs. Bill Hammond, a geodesist not part of this study, highlighted the uncertainty in determining the exact implications of these measurements due to the limited historical data available. “We often don’t know how long our current measurements are applicable for,” he stated, indicating that understanding these trends might require more extensive data collection.

In the meantime, Karegar mentions that employing GPS technology for drought monitoring is becoming an increasingly important approach. While the existing GPS stations in South Africa are somewhat sparse, comparable networks elsewhere could provide vital assistance in water management and resource allocation as this technology continues to develop.

In summary, a new study indicates that South Africa’s land is rising due to drought and substantial water loss, with an average 6 millimeter increase recorded from 2012 to 2020. Researchers used GPS data to connect land uplift to variations in water storage, highlighting potential implications for future drought monitoring. While this uplift may change with climate conditions, the evidence strongly suggests that effective water management strategies could mitigate the lasting impacts of these environmental shifts.

Original Source: www.livescience.com