A growing body of archaeological and genetic discoveries challenges the conventional timeline of human migration into the Americas, with human footprints in New Mexico suggesting an arrival around 23,000 years ago. These early pioneers likely traversed the Beringian land bridge from Asia to North America along the Pacific coastline during the last glacial maximum.
New research, set to be presented at the American Geophysical Union Annual Meeting, sheds light on the potential role of sea ice in facilitating southward movement along the Pacific Northwest. While the concept of early Americans navigating the Pacific Coast is not novel, the prevailing theory posits that, at least 16,000 years ago, people ventured south of the massive ice sheets that once blanketed much of the continent.
Considering that the ice-free corridor would remain impassable for millennia, scientists have proposed an alternative route—the “kelp highway.” This theory suggests that early inhabitants gradually migrated southward in boats, capitalizing on the abundant resources offered by coastal waters.
Evidence supporting this notion includes archaeological finds of coastal settlements in western Canada dating back to 14,000 years ago. However, a 2020 revelation posited that the presence of freshwater from melting glaciers may have created challenging currents, impeding coastal travel for these ancient populations. The interplay of climate, geography, and human adaptation unfolds as a complex narrative, reshaping our understanding of the early peopling of the Americas.
Glacial trail across hazardous sea
In an effort to gain a more comprehensive understanding of the oceanic conditions crucial to early human migration, Summer Praetorius and her colleagues from the US Geological Survey delved into climate proxies found in ocean sediment along the coast. Drawing primarily from fossilized plankton, these proxies, including the abundance and chemistry of these organisms, enabled the reconstruction of ocean temperatures, salinity, and sea ice cover.
Praetorius presented her findings at AGU23, as part of a session focused on the climate history and geology of Beringia and the North Pacific during the Pleistocene ice age. With 24,000 experts converging in San Francisco and an additional 3,000 online attendees, the week-long conference serves as a hub for Earth and space sciences.
The team’s analysis, utilizing climate models, revealed that ocean currents during the last glacial maximum, around 20,000 years ago, were more than twice as strong as they are today due to glacial winds and lower sea levels. While these conditions would have posed challenges for boat travel, the records indicated that winter sea ice persisted in the region until approximately 15,000 years ago.
Praetorius speculated that, rather than contending with formidable glacial currents, early inhabitants may have utilized the sea ice as a platform. Drawing a parallel with contemporary Arctic practices where people travel on sea ice using dog sleds and snowmobiles, she proposed the existence of a ‘sea ice highway.’ This icy route could have facilitated the migration of cold-adapted populations into North America, allowing them to navigate and hunt marine mammals.
The climate data suggests favorable conditions for migration along the coastal route between 24,500 and 22,000 years ago and 16,400-14,800 years ago, potentially aided by the presence of winter sea ice.
While confirming the use of sea ice as a means of travel poses challenges due to underwater archaeological sites, the theory offers a novel framework for comprehending how early humans may have reached North America without a traditional land bridge or straightforward oceanic routes.
Importantly, Praetorius emphasized that the sea ice highway hypothesis does not exclude the possibility of other migration routes in later periods. The team’s models indicate that by 14,000 years ago, the Alaskan current had subsided, potentially easing coastal travel by boat.
She expressed a willingness to consider all possibilities, emphasizing that ancient human ingenuity has the capacity to continually surprise researchers. The sentiment conveyed was an openness to exploring various avenues and a recognition of the unpredictable nature of discoveries related to the ingenuity of early human populations.
Resources
- ONLINE NEWS Lester, L. & American Geophysical Union. (2023, December 16). North America’s first people may have arrived by sea ice highway as early as 24,000 years ago. Phys.org. [Phys.org]
- WEBSITE Praetorius, S. K. (2023, December 15). Did a “Sea-ice Highway” facilitate early human migration from Beringia into North America along the coastal route? AGU – AGU23. [AGU – AGU23]
Cite this page:
APA 7: TWs Editor. (2023, December 18). Sea Ice May Have Facilitated the Arrival of North America’s First People 24,000 Years Ago. PerEXP Teamworks. [News Link]
