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Researchers have some theories. If early humans had moved from Africa much earlier, they would have faced fierce competition from other early human species; the north was a Neanderthal stronghold, and much of East Asia was probably populated by another extinct human lineage, the Denisovans. Models also suggest that dry periods often follow favorable windows, and this could isolate any population embarking on a migration. But the authors also note that even if the times were good and rainy, people may not have taken advantage of these periods to migrate.
The model had to make several assumptions, including that the southern strait would always be crossable by humans and that these people might have the boat technology to traverse. The model divides the region’s geography into a grid with a resolution of half a degree of latitude and longitude, or about 30 miles. This approach inevitably ignores the mosaic of vegetation and topography that exists on the ground.
Paleoclimatologist Dr. Tierney said the new paper’s climate models are too simplistic to predict what climate change was like hundreds of thousands of years ago. He also questioned some of the model’s rules; for example, people can migrate with only minimal rainfall. Dr. “I think it makes sense to make that assumption,” Tierney said. “On the other hand, the Nile River is always there. They can act that way at almost any moment.”
Similarly, Emily Beverly, an earth scientist at the University of Houston who was not involved in the research, said the authors didn’t think it existed. fresh water resources It may have served as a source of drinking water for people who migrated during dry periods.
On the other hand, paleoanthropologist Dr. Potts noted that the minimum precipitation level in the model would be “too low” to allow the successful dispersal of hunter-gatherers out of Africa. Dr. Potts, previous Research This suggests that early humans could have dispersed on the continent only when the average rainfall was more than 3.9 inches per year, and typically when there was at least 10 inches of rain. Dr. The more interesting research question in Potts’ eyes is what dispersal pathways would be present in these windows of heavy rainfall.
Perhaps the biggest question still remains unanswered. Dr. “More and more evidence is showing that we’ve been doing this over and over,” Beverly said. “The question that always stays in my mind is Why?”
Abdullah Alsharekh, an archaeologist at King Saud University in Riyadh, Saudi Arabia, who was not involved in the research, said he appreciated the paper’s study of the prehistoric Arabian climate. Dr. “The last few decades have shown that many of our questions about models outside of Africa could be greatly improved with more field research in Arabia,” Alsharekh said in an email. “What’s under those sandy deserts?”
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