The key ideas

The Sixth Extinction: An Unnatural History

Elizabeth Kolbert, 2014

Panama's golden frogs vanished in just a few years. The last pair of great auks was killed in 1844. Bats are dying by the thousands in caves. Elizabeth Kolbert travels to the places where species are disappearing, and out of these separate stories she builds one unsettling conclusion: humans have become a force on the scale of a geological catastrophe.

Who it is for

For anyone who wants to understand why species are disappearing, and to see it not in numbers but in real places and real stories.

If you want to think about why humans are so dangerous to other species, you can picture a poacher in Africa carrying an AK-47 or a logger in the Amazon gripping an ax, or, better still, you can picture yourself, holding a book on your lap.

What the book is about

Not long ago, in the Panamanian village of El Valle, golden frogs sat along the streams in such numbers that you could spot them from the trail. Then they began to disappear. Not gradually, over centuries, but in just a few years. At first nobody understood what was killing them.

Elizabeth Kolbert, a journalist at The New Yorker, goes there herself. Then to Iceland, to the Italian town of Gubbio, to volcanic vents on the seafloor, to a cave full of bats. Each chapter is one place and one species. On their own, these are separate stories. Together they add up to the conclusion the book was written for: humans have become a force on the scale of a geological catastrophe.

The book won the 2015 Pulitzer Prize. Its title is the position of many scientists, not a settled question. Across the history of life, paleontologists count five times when a mass extinction took place. Whether a sixth is happening now, or the world is only heading toward one, experts are still debating.

Idea 1. The frog that vanished before our eyes

In El Valle, Kolbert visits an amphibian rescue center. There the golden frogs live in tanks, because almost none are left in the streams. The killer turned out to be a microscopic chytrid fungus. It attacks the skin that frogs use to breathe and drink. Around the world it has struck hundreds of amphibian species.

The real twist is how the fungus got here. On its own, the fungus does not travel between continents in search of frogs. In the version Kolbert presents, people carried it, through the animal trade, shipping and travel. Status: it is established that the fungus kills amphibians; the exact routes by which it spread are still being worked out.

Extinction turns out to be a story about the present, not only about the distant past. And people can be its cause without ever meaning to kill anything.

Read in Livria

About the author

Elizabeth Kolbert is an American journalist and a staff writer at The New Yorker, where she has written about ecology and climate for many years. The Sixth Extinction won her the 2015 Pulitzer Prize for General Nonfiction.

All books by this author: Elizabeth Kolbert

Terms from the book

  • Jefferson
  • Darwin
  • Lyell
  • The New Yorker
  • Cuvier
  • Pulitzer Prize
  • Alvarez
  • Ammonites
  • Golden frogs: The Panamanian golden frog is a bright yellow amphibian (zoologically a toad of the genus Atelopus) and a national symbol of Panama. It has almost vanished from the wild because of the chytrid fungus, and the species survives in captivity.
  • Paleontologists: Scientists who study extinct animals and plants through their fossil remains.
  • Mass extinction: An event in which a large share of the species on Earth disappears within a short span of geological time. Paleontologists count five major ones in the past.
  • Chytrid fungus: A microscopic fungus that infects the skin of amphibians. It is linked to the decline and disappearance of many frog species around the world.
  • Catastrophism: Cuvier's idea that life on Earth changed through sudden catastrophes. It was long considered outdated, until the asteroid hypothesis revived interest in it.
  • Great auk: A large flightless seabird of the North Atlantic. It was wiped out by humans: the last known pair was killed in 1844.
  • Cretaceous period: A geological period from about 145 to 66 million years ago. It ended in a mass extinction that wiped out the dinosaurs and the ammonites.
  • Iridium: A metal that is very rare in the Earth's crust and more common in meteorites. Too much of it in a thin layer of clay pointed to an asteroid impact.
  • Yucatán: A peninsula in southeastern Mexico. It holds the Chicxulub crater, the mark of an asteroid that struck about 66 million years ago.
  • Nautiluses: Sea mollusks with spiral shells, relatives of the ammonites. They survived the extinction that killed the ammonites and are still alive today.
  • Ocean acidification: The drop in the pH of seawater as the ocean absorbs carbon dioxide. The process is measured; its effects on individual species are still being studied.
  • White-nose syndrome: A disease of bats caused by a fungus that grows on them during hibernation. In North America it has killed millions of bats.
  • New Pangaea: Kolbert's image, not a scientific term: by moving goods and people, humans have joined the continents together again, and species arrive in places where the locals have no defense against them.
  • Crutzen: Paul Crutzen, a Dutch chemist who won the 1995 Nobel Prize for his research on the ozone layer. In 2000 he proposed the term Anthropocene.
  • Anthropocene: A proposed name for the epoch in which humans have become the main force of change on the planet. It has not been recognized as an official geological epoch.

All terms

Similar books