New Study Reveals Why South Africa’s Land is Rising Every Year
A new study reveals that drought has caused land under South Africa to rise about 6 millimeters from 2012 to 2020, using GPS technology to link water loss to this uplift. Continued monitoring might help predict future drought impacts.
Land beneath South Africa has been steadily rising, averaging about 6 millimeters from 2012 to 2020. According to a new study, drought appears to be the primary factor behind this phenomenon. Researchers utilized a GPS-based model to understand how water loss contributed to the uplift, suggesting that such a model might help track future drought conditions.
Scientists had been aware that South Africa was experiencing land uplift for over a decade, initially attributing it to a mantle plume, a region where hot material from deep within the Earth pushes upward. However, Makan Karegar, a geodesist at the University of Bonn, found that uplift patterns aligned more closely with drought periods, especially during the severe “Day Zero” drought from 2015 to 2018, when Cape Town faced extreme water shortages. “We started to think there should be a link between this pattern and water loss,” Karegar explained.
To delve deeper, the research team analyzed GPS data from permanent stations across South Africa, capable of detecting minute changes in elevation. Published in the Journal of Geophysical Research: Solid Earth, the study unveiled the connection between regional water storage changes and land rising. As surface water reservoirs and groundwater dried up, the land elevated similarly to how memory foam reacts when pressure is released.
The researchers documented some variance geographically and seasonally but overall confirmed that the land uniformly ascended. In some regions near drained reservoirs, the uplift was even greater, reaching up to 10 millimeters. Christian Mielke, another geodesist and study coauthor, expressed surprise at the widespread uplift, indicating that they had initially expected only localized effects near urban areas.
The research validated its model by aligning land height changes with existing water storage studies and satellite data. Despite not ruling out the influence of the mantle plume, the strong correlation with water loss models indicated that drought is indeed a significant force behind the uplift. However, this uplift may not be a permanent change; should rainfall increase, land levels may decrease once again.
Experts including Bill Hammond, a geodesist at the University of Nevada Reno, emphasize that while understanding future uplift or subsidence patterns is crucial, further data and analysis are necessary to clarify the role of drought versus mantle dynamics. With just 30 years of GPS data largely collected during drought years, determining the exact contributions to land uplift remains a challenge.
Moreover, utilizing GPS for monitoring drought is an emerging strategy, noted Karegar. While South Africa has relatively sparse GPS stations, regions with closer networks could enhance water management efforts. As drought continues to be a concern, such technological applications may prove invaluable for better resource management and planning in the future.
The study confirms South Africa’s land is rising primarily due to drought, not the previously suspected mantle plume, illustrating the complex interactions between climate conditions and geological processes. Future rainfall could reverse this uplift, highlighting the importance of monitoring systems. This research underscores the potential of GPS technology in tracking environmental changes and aiding in water management as South Africa faces ongoing drought challenges.
Original Source: www.livescience.com
