New study suggests warming temperatures facilitated early human migration to Siberia

For decades, anthropologists have pondered the enigmatic Ice Age mystery: When and how did Homo sapiens journey through Eurasia? Did climate shifts, like a sudden cold snap or a warming trend, drive our early human ancestors from Africa into Europe and Asia?

A recent study published in Science Advances delves into this ancient puzzle by comparing Pleistocene vegetation around Siberia’s Lake Baikal with the oldest traces of Homo sapiens in the region. The researchers unearthed compelling evidence dating back 45,000 to 50,000 years ago, shedding light on the initial human migration across Europe and Asia.

The fresh pollen data suggests that rising temperatures fostered the expansion of forests in Siberia, making it easier for early humans to migrate there, roughly at the same time as other parts of Eurasia.

Co-author Ted Goebel, an anthropology professor at the University of Kansas, commented on this groundbreaking research: “This study addresses the long-standing debate surrounding the environmental conditions early Homo sapiens encountered during their migration into Europe and Asia around 40,000 to 50,000 years ago. It offers crucial insights into the environmental conditions at Lake Baikal, revealing unexpected warmth during this period.”

The pollen data indicates that this human dispersal coincided with some of the highest temperatures in the late Pleistocene, likely accompanied by increased humidity. The ancient pollen record paints a picture of coniferous forests and grasslands in the region, providing sustenance for foraging and hunting by early humans. According to Goebel, this environmental data, coupled with archaeological evidence, tells a new narrative.

“This contradicts some recent archaeological perspectives in Europe,” noted the KU researcher. “The key factor here is accurate dating, not only of human fossils and animal bones associated with the archaeology of these people but also of environmental records, including pollen. What we have presented is a robust chronology of environmental changes in Lake Baikal during this time period, complemented by a well-dated archaeological record of Homo sapiens’ presence in the region.”

Chikoi River valley, Trans-Baikal region. Credit: Ted Goebel

Collaborating with Goebel were lead author Koji Shichi of the Forestry and Forest Products Research Institute in Kochi, Japan; Masami Izuho of Tokyo Metropolitan University, Hachioji, Japan; and Kenji Kashiwaya of Kanazawa University, Kanazawa, Japan.

While the pollen analysis took place in Japan, Goebel and Izuho connected the pollen data with crucial evidence from the archaeological record of early human migration.

Goebel highlighted that the emergence of fully developed Homo sapiens in the archaeological record coincides with cultural and behavioral shifts. During this period, early modern humans crafted stone tools with long, slender blades, worked with bone, antler, and ivory to create tools, including some of the earliest bone needles with carved eyelets for sewing and early bone and antler spear points.

“Some of us argue that as anatomical changes were occurring, as evidenced by the fossil record, there was a simultaneous shift in behavior and cognition,” Goebel explained.

“These early humans became more creative, innovative, and adaptable. This is when we start to observe significant changes in the archaeological record, such as cave paintings. We also find mobile art, like the early carvings known as Venus figurines. In Central Europe, there’s even an ivory sculpture dating back to this early period, depicting a lion-headed man. It’s not merely replicating nature; it’s about creative expression, inventing new things, and exploring new places.”

According to Goebel, at least one human bone dating to this era has been discovered in the region.

“There is one human fossil from Siberia, although not from Lake Baikal but farther west, at a place called Ust’-Ishim,” Goebel mentioned. “Morphologically, it is human, but more importantly, it’s exceptionally well-preserved. It has been directly radiocarbon-dated and has yielded ancient DNA, confirming it as a representative of modern Homo sapiens, distinct from Neanderthals or Denisovans, or other pre-modern archaic humans.”

Goebel suggested that the earliest inhabitants of the area probably lived in extended nuclear families or small groups, as was common in other parts of Eurasia. However, due to the degradation of much archaeological evidence, certainties remain elusive.

“At Ust’-Ishim in Siberia, we have evidence of a fully modern human co-existing with the sites we’ve been discussing,” he noted.

“However, Ust’-Ishim was an isolated discovery, found by geologists eroding from a riverbank. We lack information about its archaeological context, whether it was part of a settlement or simply a solitary bone washed downstream. Consequently, linking that single individual to the archaeological sites in the Baikal region is tenuous—do they represent the same population? We think so, but definitely need more evidence.”

Source: University of Kansas

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