Not long after humankind’s emergence in Africa, Homo sapiens were off to explore the rest of the world. Yet, across the ancient timeline, the land that ancient humans walked upon was ever-changing. Sea level fluctuated dramatically over the years; at the height of the Last Glacial Maximum (LGM) around 20,000 years ago, it was so low that people established settlements in areas that are now underwater.
A new study published in the journal Comptes Rendus Géoscience provides a window into the relationship between ancient human migration out of Africa and transforming landscapes. By examining how Earth has responded to the growth and collapse of global ice sheets, researchers have pinpointed several routes from Africa to Europe and Asia that humans have taken over the past 30,000 years.
Read More: Ice Age People Lived in the Hills and Mountains, Not Just at Sea Level
Sea Level’s Impact on Migration
Reference map showing natural features cited, cities, and known routes connecting the Nile River, Foul Bay, Gulf of Suez, Red Sea, and Mediterranean Sea throughout history.
(Image Credit: Dobson et al)
Between 120,000 and 130,000 years ago — during the Last Interglacial, also known as the Eemian — the sea level was several meters higher than it is today due to the melting of polar ice caps. The sea level later dropped to -55 (-180 feet) meters 30,000 years ago, and then plummeted even further to -125 meters (-410 feet) 20,000 years ago.
When the sea level rose again after the LGM, some lands that humans had occupied were submerged in the ocean.
These long-lost regions are what Jerome Dobson, a professor emeritus of geography at the University of Kansas, calls “aquaterra.” Dobson, lead author of the new study, believes aquaterra off the coast of Egypt could be hiding ancient archaeological treasures. Dobson and his co-authors used an updated Glacial Isostatic Adjustment (GIA) model to map potential routes and settlements in Africa during the LGM.
“The exciting implication is that a lot of underwater landscapes have archaeological relevance, and this mapping gives scientists a better shot at finding them,” Dobson said in a statement. “We hope this enables people to see and explore the landscapes that were exposed during the last ice age — especially at the Last Glacial Maximum 21,000 years ago.”
Changing Travel Plans
The starting point for the journey out of Africa, according to the study, was likely in Northeast Sudan. From here, humans eventually scattered throughout the Nile Valley in south-to-north and east-to-west paths. They also may have followed a number of routes to cross the Mediterranean and the Red Sea into Europe and Asia.
Whenever the sea level was high, the Isthmus of Suez — a land bridge between the Red and Mediterranean Seas — would have been an ideal path for humans to cross. Humans may have also gone through the Gulf of Aqaba into the Levant and the Bab-el-Mandeb strait into the Arabian Peninsula (although the latter may have been too narrow a passage to travel in ancient times).
A City Concealed by Coral Reefs
The study highlighted one potential aquaterra that could have served as a major seaport: a hypothetical city the researchers call Berenice Aquaterra, which may have been a precursor to Berenice Troglodytica, an Egyptian city that had prospered 2,000 years ago.
The researchers believe that Berenice Aquaterra may have existed on the Foul Bay (on the Egyptian side of the Red Sea) when sea levels were low. Going from the Foul Bay through the Nile would have been shorter than a voyage on the Red Sea, making it an ideal alternative to reach the Mediterranean.
The researchers also suspect that archaeological evidence of Berenice Aquaterra may be tied to coral reefs off Egypt’s eastern coast . Foul Bay has a particularly high concentration of patch corals, which exist in shallow waters and need an underlying platform to grow on. These patch corals, the researchers theorize, could be lying on top of stone structures from Berenice Aquaterra that were submerged as the sea level rose.
“It is well established that coral reefs, including patch coral reefs, are dependent on a solid base,” he said. “Our circumstantial evidence is intriguing, but it demands confirmation through rigorous searches for evidence of human construction.”
Read More: Stop Searching For Atlantis And Find These 4 Ancient Underwater Cities Instead
Article Sources
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Comptes Rendus Géoscience. Alternative crossings into and out of Africa since 30,000 BP
Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
