Latest news with #MakanKaregar
Yahoo
4 days ago
- Health
- Yahoo
South Africa Is Rising Up Out of The Ocean, Scientists Reveal
As climate change intensifies, South Africa is not only becoming hotter and drier; it's also rising by up to 2 millimeters per year, according to a new study. Scientists knew this uplift was happening, but the prevailing explanation attributed it to mantle flow within Earth's crust beneath the country. The new study suggests the uplift is caused by recent droughts and the resulting loss of water, a trend linked to global climate change. The discovery emerged due to a network of global navigation satellite system (GNSS) stations in South Africa. Mainly used for atmospheric research, this network provides precise data on the height of various sites across the country. "This data showed an average rise of 6 millimeters between 2012 and 2020," says geodesist Makan Karegar from the University of Bonn. Experts had ascribed this phenomenon to the Quathlamba hotspot. A localized bulge in Earth's crust could form from the upswelling of material from a suspected mantle plume beneath the region, spurring the recent uplift. "However, we have now tested another hypothesis," Karegar says. "We believe it is also possible that a loss of groundwater and surface water is responsible for the land uplift." To explore this possibility, Karegar and his colleagues analyzed the GNSS height data along with precipitation patterns and other hydrological variables across regions of South Africa. A strong association stood out. Areas where severe droughts have occurred in recent years underwent an especially dramatic uplift of land. The rise was most pronounced during the 2015–2019 drought, a period when Cape Town faced the looming threat of "day zero" – a day with no water. The study also looked at data from the GRACE satellite mission, a joint effort by NASA and the German Aerospace Center to measure Earth's gravity field and changes in water distribution. "These results can be used to calculate, among other things, the change in the total mass of the water storage, including the sum of surface water, soil moisture, and groundwater," says University of Bonn geodesist Christian Mielke. "However, these measurements only have a low spatial resolution of several hundred kilometers." Despite this low resolution, GRACE satellite data supported the hypothesis: Places with less water mass had higher uplift at nearby GNSS stations. The team used hydrological models for higher-resolution insight into how droughts can influence the water cycle. "This data also showed that the land uplift could primarily be explained by drought and the associated loss of water mass," Mielke says. The researchers suggest that in addition to upward pressure from a mantle plume, the loss of moisture in the crust could also cause it to bulge. This is another example of the many ways climate change is tweaking the world around us, but it could also offer practical value. GNSS data, which are cost-effective and simple to collect, could offer a new way to track water scarcity, including critical groundwater resources – widely overexploited by humans for agriculture and other purposes. Given the dire threat droughts pose in South Africa, as well as many other parts of the world, this finding may provide a valuable window into water availability. The study was published in the Journal of Geophysical Research: Solid Earth. An Extreme Drop in Oxygen Will Eventually Suffocate Most Life on Earth The Ocean Is Getting Darker, Threatening All That Lives Within Your Salad Could Be Carrying Microplastics From Soil Into Your Body
Yahoo
5 days ago
- Health
- Yahoo
The land under South Africa is rising every year. We finally know why.
When you buy through links on our articles, Future and its syndication partners may earn a commission. Drought and water loss caused South Africa to rise an average of 6 millimeters (0.2 inches) between 2012 and 2020, according to a new study. Scientists have developed a new model to measure this land uplift and associated water loss using global positioning system (GPS) data. In South Africa, they found that uplift patterns correlated with droughts and with seasonal shifts between dry and wet seasons. The GPS-based model could help researchers spot signs of drought in the future, the researchers suggest. Scientists have known for more than a decade that South Africa is rising. Initially, some suspected the uplift was caused by a plume of hot rock in the mantle, Earth's middle layer, that sits beneath the country. A mantle plume forms when hot material from deep in the mantle rises and pushes against the lithosphere (the crust and upper mantle), lifting the land above it. But Makan Karegar, a geodesist at the University of Bonn in Germany, noticed that data showing uplift in South Africa correlated with periods of drought. In particular, Karegar and his colleagues spotted a pattern of uplift that corresponded to the intense "Day Zero" drought South Africa faced between 2015 and 2018, when the city of Cape Town was at risk of needing to shut off the municipal water supply. "We started to think there should be a link between this pattern and water loss," Karegar told Live Science. To investigate this relationship further, the team collected GPS data from permanent stations scattered throughout South Africa. These stations can precisely measure changes in height over time, down to fractions of a millimeter per year. In the new study, published April 9 in the Journal of Geophysical Research: Solid Earth, the scientists developed a model linking this uplift to changes in the country's water storage. Related: Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests As water disappeared from surface reservoirs, soil, and groundwater reserves, the land rose, like memory foam does after a weight is removed. The researchers observed some regional and seasonal variations in height, as well as some long-term variability. But overall, between 2012 and 2020, South Africa rose an average of 6 mm in response to water loss, the team found. Some areas near depleted water reservoirs rose as much as 0.4 inches (10 mm) during the drought. "The biggest surprise for us was that we saw an uplift over most parts of South Africa," study coauthor Christian Mielke, a geodesist at the University of Bonn, told Live Science. "We were expecting that this would probably just affect regions close to cities," near where reservoirs are concentrated. Next, the team validated their model by comparing changes in land heights across South Africa to existing models of water storage and loss. They found that the GPS-based results agreed well with predictions of water loss based on satellite measurements and climate data. While the new study doesn't rule out potential contributions from the mantle plume beneath South Africa, the strong correlations with existing models of water storage suggest that water loss is the main driving force behind the uplift. This suggests that the uplift might not be permanent. With enough precipitation and water returning to reservoirs, the land could start to sink again, Karegar said. RELATED STORIES —Earth from space: Golden river of toxic waste spills out from deadly mining disaster in South Africa —Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests —Severe drought helped bring about 'barbarian' invasion of Roman Britain, study finds But teasing out how long it might take for South Africa to rise or sink again will likely require more data, said Bill Hammond, a geodesist at the University of Nevada Reno who was not involved in the study. "We often don't know how long our current measurements are applicable for," he told Live Science. With just 30 years of GPS data from which to draw trends, many of which South Africa spent in drought conditions, it could be difficult to determine exactly how much of the uplift is due to drought versus the mantle plume, or how long it might take for the land to subside again after the drought's end, he added. In the meantime, using GPS measurements as a tool for monitoring drought conditions "is a major emerging approach," Karegar said. While South Africa's existing GPS stations are fairly spread out, stations in other parts of the world are spaced much more closely. Where these networks are established, they could help with water management, Karegar said.
IOL News
11-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
IOL News
10-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
