Source: Stanford University Date: August 10, 2007 What We Can Learn From The Biggest Extinction In The History Of Earth Science Daily — 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. Jiayong Wei, Payne's colleague, examined a block of early Triassic microbial limestone. (Credit: Jonathan Payne)...