Scientists are baffled as measurements reveal South Africa is RISING out of the ocean
Scientists have been baffled to discover that South Africa is rising out of the ocean.
New measurements reveal that the country is rising by as much as two millimetres per year in some places.
Previously, scientists thought this rapid uplift was due to a phenomenon called mantle flow - the movement of semi-molten rock beneath the Earth's crust.
But a new study claims that climate change is actually to blame.
Using a network of static GPS receivers dotted across the country, scientists made extremely precise measurements of South Africa's height.
This revealed that the areas bulging upwards the most were the areas that had experienced the most severe water shortages.
Co-author Dr Makan Karegar, from the University of Bonn, says: 'This data showed an average rise of six millimetres between 2012 and 2020.
'We believe that it [is] also possible that a loss of groundwater and surface water is responsible for the land uplift.'
Scientists have discovered that South Africa is rising out of the ocean, and they say that climate change could be to blame. Pictured: Cape Town, South Africa
Using data from South Africa's network of GPS receivers, scientists found that the country is rising an average of two millimetres per year (illustrated)
Thanks to South Africa's network of GPS receivers, known as the Global Navigation Satellite System (GNSS), scientists have known for some time that the country is rising.
Scientists had assumed that this was caused by something called the Quathlamba hotspot.
This huge, tube-like structure transports hot material from closer to the Earth's core towards the surface under the mantle.
In theory, this movement of mass towards the surface could create a bulge that would cause the land to rise up.
However, scientists from the University of Bonn have tested a new theory which they believe offers a better explanation.
By comparing the GNSS data with factors like precipitation rates across the country, they found a clear parallel in the data.
The areas that had suffered severe droughts all experienced a particularly pronounced increase in height.
Although the Earth might seem solid from our perspective, on the planetary scale it behaves much more like a rubber ball.
Although it had been thought to be a product of rising material beneath the Earth's crusts, scientists say that droughts are the real reason for South Africa's rise. Pictured: The Theewaterskloof dam near Cape Town during the 2018 drought
This graph shows the rising (red) and falling (blue) rates of South Africa's GPS stations. The rise is particularly rapid during periods of intense drought such as the years between 2015 and 2018
Co-author Christian Mielke, of the University of Bonn, told MailOnline: 'The total mass of surface water, soil moisture, and groundwater is so large that it deforms the Earth's crust - like putting pressure on an elastic ball.
'Droughts are associated with loss in these water storages. The loss of water mass due to the drought causes the Earth's crust to lift again.
In their paper, published in the Journal of Geophysical Research: Solid Earth, the researchers argue this is now happening in South Africa.
In addition to the GNSS and precipitation data, the researchers looked at data from the GRACE satellite mission - a joint project between NASA and the German Aerospace Center.
Using sensitive equipment, this satellite measures subtle changes in the Earth's gravitational field in the ground below.
Mr Mielke says: 'These results can be used to calculate, among other things, the change in the total mass of the water storage including sum of surface water, soil moisture and ground water.'
Even though the GRACE satellite only has a resolution of several hundred kilometres, the data clearly showed that the lower the mass of water in a region, the higher the uplift measured by the GPS stations.
In increasingly drought-stricken South Africa, the loss of water mass has been so pronounced that it has led to rapid increases in elevation.
Between 2015 and 2018 South Africa's Cape Town lived under threat of 'Zero Day', a day where there would be no water at all. Pictured; people queue to collect water at a spring in Cape Town during the 2018 drought
This rise was most pronounced between 2015 and 2019 during which South Africa faced one of its worst droughts in history.
In that period, Cape Town, South Africa's capital and the continent's 10th largest city, lived under the impending threat of 'Zero Day' - a day without any water.
As human-caused climate change leads to a hotter climate, droughts are becoming more common and more intense.
For example, in 2022, scientists found that climate change made the droughts which struck the Northern Hemisphere over 20 times more likely to happen.
Ultimately, the researchers believe the elevation changes in South Africa are more likely to be 'episodic' rather than permanent.
'The strong uplift we observed was mainly caused by water loss during the server drought years,' Mr Mielke adds.
'Outside of drought years, it is to expect that water reserves will replenish and land subsidence will occur.
'However, if it doesn't rain more often in future, the land could continue to rise on average until there is no more water.'
The data shows that areas with the worst droughts (brown) were also the areas with the highest uplift (red triangles). This information could help scientists monitor water levels in real time using GPS data
While Mr Mielke points out that this probably won't have any other consequences, it could provide a useful way to manage our warmer climate.
If droughts and low water levels cause the ground to rise, scientists can use the data from the GPS system to get a real-time measurement of water reserves.
This could allow scientists to measure the effects of droughts more precisely than ever before, using a method which is cheaper and easier than any other option.
Given the ongoing threat of drought faced by South Africa, and many other countries including the UK, this could become a vital water management tool.
