Fw: [CCG] Possible runaway greenhouse effect caused mega-extinction e vent @ end of Permian
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Expert Says It Was Hotter 247 Million Years Ago
April 05, 2006 � By Associated Press
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 to this."
Yet, like the huge meteor striking the Gulf of Mexico that many
scientists believe wiped out the dinosaurs, the global warming at the
end of the Permian period resulted in deadly amounts of carbon dioxide
that killed most land animals, he said.
Scientists aren't certain what caused the episode some 247 million
years ago. They estimate that temperatures ranged in the low 100s
year-round for thousands of years, he said.
"Its kind of scary that we don't know for sure what caused the worst
catastrophe of life on this planet," he said.
The graphite lines, whose significance was recently recognized, are
not unique to the caves, which were formed perhaps half a million
years ago, he said.
Roth is a geologist by training and a former science teacher who has
worked as a natural resource specialist at the monument for 17 years.
He said the new evidence suggests that "we had a runaway hothouse
effect because of the excess carbon dioxide. There was so much carbon
dioxide introduced into the atmosphere, mostly from methane from the
That carbon dioxide build-up alone would have killed off most
oxygen-breathing species, he said.
Source: Associated Press