Title: The Bering Land Bridge and the First Americans - SAPIENS
Headings: 
Searching for the Origins of the First Americans
Content: A round 30,000 years ago, climates in Northern Asia became extremely cold and dry, and there is evidence for a large-scale abandonment of much of the region. Plant productivity declined with the cold, which had an immediate impact on the animal population. Think of Arctic deserts as sets of lungs. In warmer and moister times they breathe in people and animals, then they exhale them when aridity and cold intensify. This is what happened in Siberia during the last glacial maximum—the period of maximum cold during the last ice age, from roughly 30,000 to 15,000 years ago. ( At the same time, people in other parts of the world such as Western Europe and Africa also retreated into environmental refuges in the face of either cold or drought—or both.) T he plot thickens on the land bridge in the low-lying center of Beringia. Could it have supported human life during the height of the last ice age, and if so, was it the only place that did? We now know a great deal more about the landscape there thanks to deep-sea cores and research on islands in the modern-day strait. These cores, with their diatoms, minute shells, and pollen, reveal a mosaic of cold landscapes significantly different from the harsh terrain of Siberia.