July 6, 2014

Science writer charts humans’ impact on the planet

“The Sixth Extinction: An Unnatural History” by Elizabeth Kolbert (Henry Holt, 352 pages, $28)

“The Sixth Extinction: An Unnatural History” by Elizabeth Kolbert (Henry Holt, 352 pages, $28)

They are a heedlessly aggressive species, territorial without mercy, hierarchical without conscience and, like their evolutionary cousins the chimpanzees, willful murderers of their own kind. Though not endowed by evolution with claws, large teeth, thick carapaces or speed, they have stereoscopic eyesight, opposable thumbs and tools which extend their natural inclination to kill, eat, hunt, dam, log, mine, burn, dredge, build, develop, pave, drill, fight and war. Unlike the chimpanzees, they jail and torture their own kind, at times for sport or pleasure. And, unlike the chimpanzees, and indeed unlike any other species in the 5-billion-year history of the planet, they are, by their own actions, bringing about the large-scale extinctions of many varieties of animal and plant life, something that, heretofore, only geologic or astronomic causes could accomplish.

They are we. They are you and I.

Elizabeth Kolbert, an accomplished science writer and regular contributor to The New Yorker magazine, has written a dispassionate, moving, and thorough book documenting in detail the current despoliation of the biosphere, a depressing and distressing message of species decline, deforestation, ocean acidification, reef death, rainforest loss, large mammal disappearance and a complex of other disasters. All of it is culled from Kolbert’s prodigious knowledge of climatology, stratigraphy, glaciology, herpetology (frogs and other amphibians are dying out faster than any other class of animal, with bees not far behind), dendrology, forest ecology and more. For example, the International Union for Conservation of Nature, a Swiss-based non-profit scientific organization, lists the status of more than 71,000 species, 30 percent of which are threatened. One third of freshwater mollusks, sharks and rays, one quarter of all mammals, a fifth of reptiles, and a sixth of all birds are headed for oblivion.

Once the science of extinction got started in the late 19th century, geologists and paleontologists began to document large die-offs. There have been five, including the great dinosaur catastrophe linked to an asteroid collision that annihilated reptiles in short order. The end-Permian extinction took care of 95 percent of species, almost all of them aquatic. Of the five previous great extinctions – defined as a die-off of at least 75 percent of all species on the planet – four were drawn-out geologic affairs taking millions and millions of years. Our species was not around to either witness or cause these events.

Because the current human-caused mass extinction involves so many species, Kolbert selects her subjects by chapter, based on how much each loss tells us about the ways species go extinct, linking each to human activity. For example, humans emit carbon dioxide in huge quantities, a gas that is absorbed in mass by the oceans, which in turn, turns seawater acidic. The oceans are one-third more acidic than they were in 1800; by the end of this century they’ll be 150 percent more acidic. Acidic oceans leads to virulent algae blooms, alterations in the cell function of marine organisms and a radical reduction in the availability of carbonate ions in water. Simply put, shelled organisms can’t make shells. Coral cover in the Great Barrier Reef has declined by 50 percent in the past three decades. Because some 9 million life forms live in coral reefs, a whole, beautiful, complex and precious ecology will soon disappear forever.

Reading Kolbert’s previous book, “Field Notes from a Catastrophe” (2006), about climate change, with its reports of rising ocean levels, spreading deserts, increasing disease vectors and intensifying storms, along with “The Sixth Extinction,” reinforces Kolbert’s notion that human beings are somehow innately rapacious, with a “Faustian restlessness.”

The great American writer Henry Miller once observed that we were not put on this planet to give it order; instead, we’re here to seek its order and live with it in harmony. Still, the Chinese kill sharks only to blandish their vanity in soup, or poach elephants and rhinos to make ivory bracelets and to enhance male potency. Mao waged war on songbirds, which were eating the people’s corn. Americans slaughtered many hundreds of millions of beautiful passenger pigeons, until they were no more.

It would seem that our human destiny is disharmony, a fate that must puzzle even the chimpanzees we place in cages and dissect.

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