South Africa has been experiencing a phenomenon where its land is rising by up to two millimeters annually. This unexpected change in the country’s topography was initially attributed to geological forces such as mantle plumes beneath the Earth’s crust. However, recent research from the University of Bonn suggests that droughts and subsequent water loss are the primary cause of this land uplift.
The University of Bonn’s sophisticated network of permanent GPS receivers measures South Africa’s height and position with precision, down to the millimeter. The data collected showed an average rise of six millimeters between 2012 and 2020, with the Western Cape province experiencing the most significant land uplift, gaining 5-6 millimeters in elevation.
The researchers discovered a striking parallel between drought-prone regions and greater land uplift, according to precipitation patterns observed by the GRACE satellite mission. The data confirmed that regions hit hard by droughts had noticeably more land uplift at GPS stations within them. High-resolution hydrological models further corroborated this finding.
According to Dr. Makan Karegar from the Institute of Geodesy and Geoinformation, “The loss of groundwater and surface water is responsible for the land uplift.” This theory suggests that when a region loses water mass, the surrounding land masses bulge upwards due to decreased compression.
This study provides new insights into drought conditions and their impact on the environment. With climate change altering precipitation patterns, droughts are expected to become more severe. GPS-based monitoring can now precisely track drought conditions by sensing land uplift caused by water depletion, making it crucial for monitoring underground water reserves used for drinking, irrigation, and industry.
Source: https://interestingengineering.com/science/south-africa-rising-ocean-drought