The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert

The end-Permian or Permo-Triassic extinction was the biggest of the Big Five, an episode that came scarily close to eliminating multicellular life altogether.

This is the case even though a hundred million years from now, all that we consider to be the great works of man—the sculptures and the libraries, the monuments and the museums, the cities and the factories—will be compressed into a layer of sediment not much thicker than a cigarette paper.

Since the start of the industrial revolution, humans have burned through enough fossil fuels—coal, oil, and natural gas—to add some 365 billion metric tons of carbon to the atmosphere. Deforestation has contributed another 180 billion tons. Each year, we throw up another nine billion tons or so, an amount that’s been increasing by as much as six percent annually. As a result of all this, the concentration of carbon dioxide in the air today—a little over four hundred parts per million—is higher than at any other point in the last eight hundred thousand years. Quite probably it is higher than at any point in the last several million years.