CAVE JUNCTION, Ore. - John Roth shined his flashlight on a black streak flowing through the cream-colored marble forming the walls of the Oregon Caves. The graphite line is graphic evidence of dramatic global warming that consumed so much oxygen that it nearly wiped out all life on the planet 247 million years ago, said the natural resources specialist for the Oregon Caves National Monument. "It was the biggest extinction by far of all time," he said. "Geologists and paleontologists all agree on that. ... The extinction that killed the dinosaurs about 65 million years ago, that wasn't anything compared...
