The Decline and Fall of the Human Empire: Why Our Species Is on the Edge of Extinction

Without drastic action, “Homo sapiens will disappear from the Earth within the next 10,000 years,” according to this unpersuasive warning. Nature editor Gee (A (Very) Short History of Life on Earth) argues that modern humans’ relatively limited genetic diversity combined with predicted population declines in most countries risks setting humans on a path toward extinction. He points out how Neanderthals’ even narrower genetic diversity put them at an evolutionary disadvantage when competing for resources with Homo sapiens, forcing them to either mate with sapiens or die out. Unfortunately, Gee’s solution for humanity to avoid a similar fate by establishing space colonies defies logic. According to Gee, the isolation of space would aid humanity’s survival by producing genetically distinct subpopulations that can interbreed with groups on Earth or elsewhere in space to create offspring with the best traits of both communities, in a similar fashion to what happened after Homo erectus diversified into Neanderthals, Homo sapiens, and other human species more than 315,000 years ago. However, this argument is severely undermined by Gee’s discussion of how isolated breeding pools risk concentrating genetic deficiencies and vulnerability to disease, natural disasters, and other mass casualty events, as befell the Neanderthals. This strains credulity.Agent: Jill Grinberg, Grinberg Literary Management. (Mar.)