- The world's oldest active termite mounds have been discovered in Namaqualand.
- The little hills, inhabited by the southern harvester termite, date back 34 000 years and were already ancient when woolly mammoths still roamed the planet.
- These termite mounds act as carbon sinks - in other words, they remove carbon dioxide from the atmosphere needed to combat climate change.
- For climate change news and analysis, go to News24 Climate Future.
The world's oldest and active termite mounds have been discovered in Namaqualand, dating back 34 000 years - or since before the last Ice Age when woolly mammoths still existed.
The little hills were discovered by researchers from Stellenbosch University's Department of Soil Science and Earth Sciences, who collaborated with experts from the Institute for Nuclear Research in Hungary. The findings were published in May 2024 in the journal Science of The Total Environment.
The mounds are inhabited by the southern harvester termite. The previous oldest inhabited mounds - by a different termite species - were discovered in Brazil, and they are 4 000 years old, Stellenbosch University said in a statement.
For this study, the researchers dated mounds in the Buffels River Valley, and they are even older than cave paintings found in Europe.
"Recent radiocarbon dating has revealed that these mounds are far older than any previously known, with some dating as far back as 34 000 years – that's older than the iconic cave paintings in Europe and even older than the Last Glacial Maximum, when vast ice sheets covered much of the northern hemisphere," said Dr Michele Francis, a senior lecturer in the department of soil science at Stellenbosch University.
"To put it in perspective, these termite mounds were already ancient when woolly mammoths still roamed the Earth. During the Last Glacial Maximum, around 20 000 years ago, massive ice sheets covered parts of North America, Europe, and Asia.
"These mounds were already thousands of years old by then, providing a living archive of environmental conditions that shaped our world," Francis added.
Importantly, the mounds serve as valuable records of the prehistoric climate conditions:
The 'heuweltjies' (little hills) have shown that during their formation, the region experienced significantly more rainfall than today. This wetter climate allowed for minerals such as calcite and gypsum to dissolve and move down to the groundwater. What is interesting is that Namaqualand still has sporadic episodes of intense rainfall, like last winter, which would re-activate the process.
According to the study, the process of soil calcite leaching into groundwater is useful for storing carbon (from the atmosphere) in the ground for a long timeframe.
Essentially, the mounds act as carbon sinks, by removing carbon dioxide naturally from the atmosphere and storing it underground or in soil. Carbon dioxide is one of the greenhouse gases that contribute to rapid global warming, which is why this is important in combating climate change.
The discovery will form part of a study on their carbon storage potential, funded through a joint grant by the National Science Foundation in the US and South Africa's National Research Foundation.
Francis noted that the mounds occur over the west coast area from Stellenbosch to Namaqualand and the team is studying their carbon storage potential - the rainfall variation impacts vegetation for termites and makes the carbon storage potential different.
Another researcher and PhD candidate, Teneille Nel, is currently in Germany, dating carbon in mounds from more places.
"By studying these mounds, scientists can gain a better understanding of how to combat climate change, utilising nature's own processes for carbon sequestration (removal from the atmosphere and storage).
"They also highlight the importance of preserving our natural world, as these tiny engineers have been shaping our environment for tens of thousands of years," added Francis.
Francis believes the mounds should be globally recognised as a natural wonder - given what they reveal about ancient ecosystems, saying:
The discovery of these mounds is akin to being able to read an ancient manuscript that changes everything we thought we knew about history.
"These mounds not only illuminate the past but also offer vital clues for our future. As we continue to uncover the secrets of these ancient structures, they stand as a reminder of the delicate interplay between climate, environment, and life on Earth," Francis added.