We Aren’t Destroying the Earth

David Biello in The New York Times:

BielloSince humanity left Africa some tens of thousands of years ago, large land animals across the world have had a mysterious habit of dying out: giant kangaroo, woolly mammoth, glyptodont, to name a few. As Alfred Russel Wallace put it, we live in a world that lacks “all the hugest, and fiercest, and strangest” animals. It’s no wonder that invasive species are considered a big threat to wildlife, and none more so than the one species invasive on six out of seven continents: us. Hence the “ecological despair” that the conservation biologist Chris Thomas identifies early in his provocative new book. “A mass extinction is in full swing, and prognoses for the future seem dire. For these reasons, we have gone so far as to describe ourselves as the scourge of the Earth, and as exceeding our planetary boundaries,” he writes. But Thomas is not interested in feeding this despair. Rather, he makes an argument considered apostasy by many: People’s impact on the planet has not been that catastrophic. In other words, nature is more complicated, as the book explores in some detail. People spreading out across the globe and building international trade networks have reunited the continents in a kind of virtual supercontinent, mixing plant, animal, microbe and fungal species in a way unseen since Pangaea, more than 200 million years ago. Human alterations to the planet’s surface — like the conversion of most of the world’s grasslands into pasture and crops — have transformed the environment in which all other species thrive or die. As a result, some plants, animals, microbes and fungi win, and some lose.

Consider the sparrow. This bird of the Asian steppe has spread across the world because of all the man-made farms, towns and cities that resemble their original habitat. Plus the unique nature of man plays a role. In fact, just one man, whose name we know — Eugene Schieffelin — is responsible for first releasing into North America the millions of sparrows we know today, mostly because the immigrant bird was mentioned in the plays of Shakespeare. There are an estimated half-billion of these birds around the world now, and they are breaking up into independent species. The book is filled with such lovely anecdotes, many from Thomas’s own rich life of natural adventure, whether surveying sparrows in Italy or encountering pygmy elephants in Borneo.

More here.