02-06-2025
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.'
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.
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.
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.
WHAT CAUSED THE SUMMER 2018 GLOBAL HEATWAVE?
There are several leading theories as to what caused the global heatwave, according to University of Reading climate scientist Professor Len Shaffrey.
1. Climate Change: Temperatures are increasing globally due to the burning of fossil fuels increasing concentrations of atmospheric carbon dioxide. The global rise in temperatures means that heatwaves are becoming more extreme. The past few years have seen some record-breaking temperatures in Europe, for example the 2015 heatwave and the 2017 'Lucifer' heatwave in Central Europe. Unusually warm summer temperatures have been recorded elsewhere, for example in Canada and Japan, and climate change is very likely to have played a role here as well.
2. North Atlantic Ocean Temperatures: Temperatures over the North Atlantic Ocean can play a role in setting the position of the jet stream, which in turn has a profound impact on the weather we experience in the UK and Ireland. This summer has seen relatively warm North Atlantic Ocean temperatures in the subtropics and cold ocean temperatures to the south of Greenland. These are thought to be influencing the high pressure over Europe and pushing the jet stream further northwards.
3. La Nina: Every few years, ocean temperatures in the Tropical Pacific swing between being relatively warm (known as El Nino) and cool (La Nina). Since October last year the Tropical Pacific has been in a La Nina phase. La Nina is sometimes associated with cold winters in North Western Europe (for example the winter of 2010/11 and the recent cold spell in March 2018). However, this year's La Nina had started to weaken around April and had almost gone by June when the current dry spell in the UK began.
4. It's the weather: The above factors influence type of the weather get in the UK and Ireland but good or bad luck also plays a role, especially for very unusual weather such as the current hot and dry spell. This summer is no different and the hot and dry weather is partly due a combination of North Atlantic Ocean temperatures, climate change and the weather. Should weather patterns continue as they are then we might expect this summer will turn out to be as hot and dry as the extreme summer of 1976.
