The Sahara desert is the largest sand desert on Earth, covering an approximate area of 9.4 million square kilometers. Recently, scientists from the Bjerknes Centre for Climate Research in Bergen have re-dated the origin of the desert. The result shows that the Sahara in Africa was formed much earlier than previously thought, around seven million years ago, long before the beginning of the Ice Age.
Despite its vast size, the Sahara desert is shrinking due to climate change. Geographer Stefan Kröpelin from the University of Cologne’s Africa Research Center has observed clear signs of a greening Sahara during his repeated visits to the same locations in the desert. However, the Sahara is not only providing new insights into the future, but also into the past. Research by Zhongshi Zhang from the Bjerknes Centre for Climate Research in Bergen shows that the origin of the Sahara dates back much further than previously believed.
Until now, it was thought that the Sahara’s history went back only about two million years. However, new findings from sand deposits in the African Chad region suggest that the desert’s origin can be traced back over seven million years. To support these findings, Zhang and his team developed a comprehensive climate simulation of the events of the last 30 million years, going back to the Paleogene epoch. The simulation revealed that the early signs of the Sahara desert’s formation can be traced back to the early period of the Miocene, the Neogene epoch, about 20 million years ago.
The re-dating of the Sahara’s origin also has implications for the theory of our own evolution. The early climate change that transformed a green environment into a dry landscape may have influenced the adaptation of our first ancestors, the apes. The shrinking of the Sahara desert due to climate change is a reminder of the importance of understanding the Earth’s past and present to prepare for the future.
