Is the Modern Mass Extinction Overrated?

After decades of researching the impact that humans are having on animal and plant species around the world, Chris Thomas has a simple message: Cheer up. Yes, we’ve wiped out woolly mammoths and ground sloths, and are finishing off black rhinos and Siberian tigers, but the doom is not all gloom. Myriad species, thanks in large part to humans who inadvertently transport them around the world, have blossomed in new regions, mated with like species and formed new hybrids that have themselves gone forth and prospered. We’re talking mammals, birds, trees, insects, microbes—all your flora and fauna. “Virtually all countries and islands in the world have experienced substantial increases in the numbers of species that can be found in and on them,” writes Thomas in his new book, Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction.

Thomas is a professor of conservation biology at the University of York in England. He is not easily pigeonholed. He has been a go-to scientist for the media and lawmakers on how climate change is scorching the life out of animals and plants. At the same time he can turn around and write, “Wild geese, swans, storks, herons and cranes are returning as well, and the great whales, the largest animals ever to have lived on Earth, are once more plying their way across our seaways in numbers after centuries of unsustainable butchery.” Glass half empty, meet Chris Thomas.

Inheritors of the Earth collects years of Thomas’ field research, illuminating plant and animal species—notably one of his specialties, butterflies—flourishing all over the Earth. Thomas also puts big ideas on display. Humans are just another animal on the planet, he wants us to know. Our actions are not outside the engine of evolution, even though we have the most horsepower. Environmentalists need to stop fencing off nature from humans, he argues, understand the mechanics of evolution better, including our role in it, and quit being such nattering nabobs of negativity. Once they do all those things, real conservation has a chance. The Sixth Great Extinction, he tells us, is premature.

There may be a bit too much of Dr. Pangloss in , and despite its ample footnotes, I would have liked to have learned more about how Thomas quantifies some of his general assertions about increases in species. I did ask Thomas to cite the research he has drawn from to support his views, and he responded with the names of five scientists who have influenced him. You can read his answer in a footnote at the end of the interview. (I didn’t include it because it seemed kind