December 19, 2010

The Cretaceous SUV's ?

It never ends!

Gaseous dinosaurs that ‘might have contributed’ to global warming

by Ned Rozell

SAN FRANCISCO — The emissions of northern dinosaurs may have led to a warmer planet 70 million years ago, said a scientist attending the 2010 American Geophysical Union Fall Meeting in mid-December.

Dinosaur hunters have found preserved footprints of hadrosaurs in rocks all over Alaska, including: Denali National Park, near the Colville River north of the Brooks Range, at Aniakchak National Monument and Preserve on the Alaska Peninsula, and in Yukon-Charley National Park and Preserve.

Tony Fiorillo of the Museum of Nature and Science in Dallas started thinking about all those hadrosaurs being plant-eating dinosaurs as large as elephants and their nickname, bestowed by paleontologists: cows of the Cretaceous.

At AGU, Fiorillo presented his idea that hadrosaurs were spread across the landscape at numbers comparable to today’s caribou, a calculated “standing crop” of 500,000 hadrosaurs in Alaska 70 million years ago.

He figured the output of one hadrosaur equaled that of about 10 cows, and then he extrapolated. Because there are published reports on how much methane wafts from the average cow pie, Fiorillo figured that the Alaska hadrosaurs might have contributed an impressive amount of the greenhouse gas to the atmosphere. In short, “hadrosaurs may have contributed to a warmer Arctic,” he said.

The world of the hadrosaurs might also have featured wildfire behavior similar to what we see in the north today, Fiorillo said. The Alaska climate experienced by dinosaurs was probably comparable to current trends in the region between Portland, Oregon and Calgary in Alberta, Canada.

“It must have been delightful,” he said. “Lush vegetation and high mountains in the distance.”

Winter was perhaps the dry season 70 million years ago, which may have made spring the fire season. Fiorillo and other scientists have found charcoal embedded in some fossil sites. He thinks fires and dinosaurs may have been responsible for the open landscape upon which the dinosaurs apparently lived.

“Fire might have made clearings, and (plant-eating dinosaurs) maintained them, something like giraffes and hippos do today,” he said.

No comments:

Post a Comment