Study Finds South Africa’s Land Uplift Linked to Drought Conditions
A new study reveals that South Africa’s land has risen an average of 6 mm from 2012 to 2020 due to drought. Researchers used GPS data to identify this uplift and its correlation with water loss. The findings suggest that while the uplift is currently linked to drought, rain could reverse this trend in the future.
In a recent study, researchers have unveiled that the land under South Africa has risen noticeably, approximately 6 millimeters or 0.2 inches between 2012 and 2020. This uplifting has been largely attributed to drought conditions affecting the region. Using advanced GPS technology, scientists have devised a model that links these changes in land elevation to the extensive loss of water resources due to droughts, indicating a potential method to predict future drought conditions.
The uplift phenomenon, which was observed over the past decade, sparked various theories. Initially, there were speculations regarding a plume of hot rock in the Earth’s mantle beneath South Africa as the reason for the uplift. However, geodesist Makan Karegar from the University of Bonn noticed a significant correlation between land elevation changes and drought periods. This connection was highlighted during the infamous “Day Zero” drought that troubled Cape Town from 2015 to 2018, where the city faced a severe water shortage.
The research team utilized data from GPS stations distributed across South Africa to monitor minute alterations in land height. Their findings revealed that as water was drained from both surface reservoirs and groundwater resources during the droughts, the land responded by rising—similar to how memory foam rebounds after weight is lifted. Although variations were recorded in different regions, the overall trend during the reported timeframe confirmed an average rise of 6 millimeters linked directly to water loss.
Study coauthor Christian Mielke expressed surprise at the widespread nature of the uplift, suggesting that it impacted more regions than initially expected, which were primarily thought to be near urban areas with significant water reservoirs. Upon validating their model, the team discovered a striking alignment between the GPS-derived elevation changes and satellite data on water storage, reinforcing their conclusion that water depletion has been the predominant cause of land uplift, even while not fully ruling out contributions from the mantle.
The implication of these findings raises concerns that the uplift may not be permanent. Karegar emphasized that returning rainfall could lead to a gradual sinking of the land as water levels are restored in reservoirs. Bill Hammond, a geodesist from the University of Nevada Reno, noted that accurately predicting the duration of uplift or subsequent subsidence remains challenging due to limited data and the historical prevalence of drought in the region.
Currently, the GPS model employed for monitoring land elevation changes presents a novel approach to understanding and anticipating drought impacts. Karegar pointed out that while South Africa’s GPS stations are scattered, tighter networks in other global locations could provide significant insights into water management strategies. This study, published in the Journal of Geophysical Research: Solid Earth, reflects a critical intersection of geodesy, environmental science, and sustainable water practices—underscoring the ongoing necessity for careful monitoring of these trends in the face of climate challenges.
The recent findings indicate a significant land uplift in South Africa due to water loss amid ongoing drought conditions. Using GPS technology to monitor these changes has revealed a crucial link between drought and land elevation, with implications for future water management strategies. The potential for the uplift to reverse with increased rainfall further emphasizes the need for continuous monitoring and data collection in the region.
Original Source: www.livescience.com
