New Study Reveals South Africa’s Rising Land Linked to Drought Conditions

A GPS-based study shows that South Africa’s land is rising due to drought, with an average increase of 6 mm from 2012 to 2020. The research, linking land uplift to water loss, was conducted by scientists from the University of Bonn. It indicates that while geological factors might exist, the primary cause is drought, suggesting future implications for land stability and water management.

New studies reveal that South Africa is experiencing a significant geological occurrence: the land is rising, and it appears that drought is a key player in this phenomenon. Between 2012 and 2020, land elevation increased by an average of 6 millimeters (0.2 inches), largely due to water loss from soils and reservoirs. Researchers utilized GPS technology to track this uplift, discovering correlations with patterns of drought and seasonal weather changes, potentially enhancing future drought detection methods.

For over a decade, scientists suspected that a hot rock plume beneath the Earth’s mantle might be responsible for this uplift. However, geodesist Makan Karegar from the University of Bonn observed a striking pattern linking land rise to drought periods. Notably, this correlation was evident during Cape Town’s alarming “Day Zero” drought from 2015 to 2018, when stringent water restrictions were imposed. “We started to think there should be a link between this pattern and water loss,” Karegar explained.

The research team gathered extensive GPS data from various permanent stations throughout South Africa, which can measure height changes with remarkable precision. Their findings, recently published in the Journal of Geophysical Research: Solid Earth, demonstrate a clear connection between land uplift and variations in water storage across the country.

As water levels decreased in reservoirs and groundwater sources, the land uplift mirrored this loss—similar to how memory foam returns to shape once weight is lifted. While there were some regional inconsistencies in the data during the study period, the overall trend showed a marked land rise, with some areas experiencing even more pronounced changes of up to 10 millimeters during the drought.

Christian Mielke, another geodesist from the University of Bonn, expressed surprise at the extensive uplift across South Africa. “The biggest surprise for us was that we saw an uplift over most parts of South Africa,” he shared. The expectation was that only specific urban regions, close to water sources, would be affected.

The team further validated their findings by juxtaposing the GPS data on land elevation with existing water storage and loss models. Their results aligned remarkably well, indicating that while the mantle plume may still play a role, the prevailing cause of the uplift is indeed the substantial reduction in water resources.

This raises questions regarding the permanence of the uplift. Karegar pointed out that if precipitation increases and water begins to replenish these reservoirs, the land may sink back down. However, experts like Bill Hammond from the University of Nevada Reno caution that determining the timeline for these changes is complex and requires more in-depth data, particularly regarding the balance between drought effects and the mantle’s influence.

In the interim, utilizing GPS technology to monitor drought conditions signifies a burgeoning strategy in environmental science. While South Africa’s GPS stations are somewhat sparse, other regions may leverage denser networks for better water management practices, as Karegar mentioned. This presents exciting possibilities for future research and its applications in addressing water shortages.

In conclusion, a recent GPS-based study reveals that drought conditions are a significant factor in the land uplift experienced in South Africa from 2012 to 2020. While there are possible geological factors at play, such as a hot rock plume beneath the crust, data indicates that water loss is the primary cause of the average 6 millimeter rise in land elevation. This finding may have implications for water management in the face of changing climate conditions, suggesting the potential for land to sink again with sufficient rainfall.

Original Source: www.livescience.com