Using Climate to Model Ancient Human Migration

Over the past 30 years, studying the evolution of hominins (humans and their close ancestors) has shifted from locating fossils and artifacts to understanding the ecological drivers behind where these items are found. Since these materials were first discovered, many drivers of hominin evolution have been hypothesized ( 1 ), but testing these ideas is difficult because of limited data on environmental and climate factors that could have influenced migration and because of the challenges of establishing the age of the sediments in which the materials are found. On pages 693 and 699 of this issue, Margari et al. ( 2 ) and Ruan et al. ( 3 ), respectively, address these difficulties by modeling how both climate and ecosystems changed during various periods of time over the past 3 million years A similar approach was also described by Zeller et al. ( 4 ). These models use current understanding of the environment and climate to extrapolate from incomplete records and provide ecological context for evolutionary changes.