Life Finds a Way: Welcome to Anthropocene Park.

• Author: Bailey, Ronald
• Position: BOOKS - Chris D. Thomas' "Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction" - Critical essay

HUMANITY ISN'T DESTROYING the natural world. We're changing it. And in many ways, our changes are creating richer and more vibrant ecosystems.

That's the persuasive and liberating argument advanced by the York University conservation biologist Chris D. Thomas in his riveting new book, Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction. "It is time for the ecological, conservation and environmental movement--of which I am a life-long member--to throw off the shackles of a pessimism-laden, loss-only view of the world," he writes. Instead, he thinks a thriving world of exotic ecosystems and biological renewal is at hand. By the time readers have finished this carefully researched treatise, they should agree.

Thomas' thesis isn't exactly the conventional wisdom. In her Pulitzer-winning 2015 book The Sixth Extinction (Henry Holt and Co.), journalist Elizabeth Kolbert argues that current species losses are comparable to the five prior mass extinctions that have occurred in the past 540 million years. In each case, around 75 percent of then-living species were killed off. Kolbert and the biologists she cites suggest not just that a sixth such event is underway but that human activities are the chief cause of the disaster.

Last year, the Stanford biologist Paul Ehrlich made a similar argument in the Proceedings of the National Academy of Sciences, concluding that all trends are "painting a dismal picture of the future of life, including human life." Inheritors of the Earth brilliantly demonstrates that there are good scientific reasons to doubt these dire prophecies.

Thomas forthrightly acknowledges that the "'extinction crisis' is real" and "we are in the process of losing many species that existed before humans arrived on the scene." Researchers estimate that 178 of the world's largest mammal species disappeared before 1500. Since then, the International Union for the Conservation of Nature reports that 2 percent of mammals, 1.6 percent of birds, and 2 percent of amphibians have gone extinct. "This loss is devastating," Thomas writes, "but, luckily, it isn't the whole story."

He observes that by 2000, human beings accounted for about 30 percent of the biomass of all land mammals, with our domestic livestock making up 67 percent of the rest. Due to human activities, the total amount of mammal flesh is "over seven times greater than it was before humans came along." And this does not take into account the billions of domestic...