Wednesday, March 05, 2014

The Sixth Extinction

Choosing a depressing book to read during the coldest week of the coldest winter of the past two decades perhaps was not a good idea, but the latest visit from the polar vortex gave me a good excuse to stay inside to finish Elizabeth Kolbert's The Sixth Extinction.

Kolbert isn't providing a newsflash; scientists have been telling us for many years that we are living in a period of species extinction not witnessed since the event at the end of the Cretaceous period that wiped out the dinosaurs, which fossil evidence indicates was the fifth time in the planet's history that the diversity of life cataclysmically contracted. Species are disappearing at an alarming and accelerating rate, and this time, the villain is one very successful "weedy" species, an invasive species like no other.

Even though I consider myself reasonably educated on ecological issues, before reading this book, I had a simplistic notion of the cause of the current species extinction. I believed it to be largely a result of human-induced climate change. But as Kolbert explains, the warming of the planet is merely accelerating a process that started when homo sapiens walked out of Africa some 100,000 years ago. 

The rapidly-unfolding climate change brought about by the burning of fossils fuels is certainly a major factor driving species extinction, as it alters habitat, acidifies the oceans and changes the composition of the air we breathe. But other human activities also have a significant impact, including predation (hunting, poaching), habitat destruction, and global commerce that spreads invasive species.

Kolbert visits around the globe with scientists in several disciplines to describe their research and, sometimes, their near-hopeless efforts to save a disappearing species. These are interesting and admirable people, but probably not the sort with whom you'd want to spend much time on a gray winter day. Fortunately for Kolbert, most of her field visits occurred in the tropics, so at least that provided some relief to this depressing tale with her descriptions of the wonders and beauties of the endangered species she saw in the Amazon rainforest and the Great Barrier Reef. But then, sadly, we are left to mourn for them, and for ourselves.

Despite the grim subject matter and the apocalyptic title, the author does not take an alarmist stance or issue a rallying cry to humans to mend our ways before it is too late. The tone here is more fatalistic, a sad witness to an inevitability rather than a call to action. Also, Kolbert makes clear that it's the diversity of life rather than life itself that's at stake, and we simply don't know yet whether the loss of diversity may threaten the species that caused it.

This book is an excellent piece of science journalism, well-written and researched, with an impressive bibliography. I recommend it, but if winter has already depressed you, wait until spring to read this.

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