Approximately 250 million years ago, vast numbers of species disappeared from Earth. This mass-extinction event may hold clues to current global carbon cycle changes, according to Jonathan Payne, assistant professor of geological and environmental sciences. Payne, a paleobiologist who joined the Stanford faculty in 2005, studies the Permian-Triassic extinction and the following 4 million years of instability in the global carbon cycle.

In the July issue of the Geological Society of America Bulletin, Payne presented evidence that a massive, rapid release of carbon may have triggered this extinction.
"People point to the fossil record as a place where we can learn about how our actions today may affect the future course of evolution," Payne said. "That's certainly true: The deep geologic record provides context for modern events. We may miss very important processes or underestimate the magnitude of changes in the future by using only the past couple thousand years as a baseline."