This reframing matters because it changes how we think about the capacity of ancient humans to colonize extreme environments.

The assumption of limitation — the assumption that there were environmental thresholds that ancient peoples could not cross until climate conditions became more favorable — may be systematically wrong.

Ancient humans appear to have been more capable, more adaptable, and more willing to push into challenging environments than older models assumed.

This has implications for understanding the colonization of the Americas.

The crossing of Beringia and entry into the Americas occurred during or near the Last Glacial Maximum — not in a period of favorable climate, but in a period of severe cold, extensive glaciation, and dramatically different geography and ecology from the present.

The people who accomplished this crossing were not waiting for better conditions.