New research published this month reinforces the view that this event, called the End of Permian - or "Mother of all Extinctions" - was set off not by an asteroid impact but by an internal disturbance that released a burst of carbon dioxide into the atmosphere and heated the planet.
It's not the heat itself but the resulting reordering of the living world that would cause a massive die-off, said Pennsylvania State University geoscience professor Lee Kump. Natural selection proceeds. Life extinguishes other life.
According to a theory that Kump proposed several years ago to explain the Mother of all Extinctions, excess heat hinders oxygen from dissolving into the oceans. Oxygen-starved oceans become hostile to fish, plankton, and other familiar life, but friendly to sulfur-using bacteria. They poison other species by exhaling hydrogen sulfide.
Peter Ward, a professor of biology and earth and space sciences at the University of Washington, popularized Kump's theory in his 2007 book Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future.
In his vivid visualization: "Most of the shoreline is encrusted with rotting organic matter. Silklike swaths of bacterial slick now putrefying under the blazing sun, while in the nearby shallows mounds of similar mats can be seen growing up toward the sea's surface. . . . From shore to the horizon, there is but an unending purple color - a vast, flat, oily purple, not looking at all like water . . . no fish break its surface, no birds of any kind . . . we are under a pale green sky and it has the smell of death and poison."
