Climate changes facilitated human migration into the Americas.

Evidence

But no humans had yet set foot in the Americas. … They got their chance thanks to major changes in climate. First, about 20,000 years ago, an intensification of the Ice Age locked up a great deal of water in ice-sheets and glaciers, leading to a huge fall in sea level. The sea between Russia and Alaska (the Bering Strait) became a wide and easily passable land bridge. — Neil MacGregor, A History of the World in 100 Objects, 122

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 122
• XREF: connects to: Changes in sea level allowed animals to migrate to the Americas. — Neil MacGregor, A History of the World in 100 Objects, 122

Broader Connections

• Changes in sea level allowed animals to migrate to the Americas. #expands (0.70) — Neil MacGregor, A History of the World in 100 Objects, 122