One professor would agree:
December 9, 1997
Today's atmosphere would doom dinosaurs
PORTLAND (AP) -- Even without global warming, dinosaurs would overheat and perish in the Earth's atmosphere today and the giant flying pterosaurs would fall out of the sky, an Oregon researcher says.
The Earth's atmosphere may be only one-eighth as dense as it was when dinosaurs flourished, says Oregon State University professor Octave Levenspiel, who presented his theory last month at the American Institute of Chemical Engineers annual meeting in Los Angeles.
Large dinosaurs would die today because of poor heat transfer, he said.
"When creatures become very large, they have more trouble removing heat," said the emeritus professor of chemical engineering at Oregon State University. "A denser atmosphere removes heat faster. An atmosphere eight times denser would have allowed the giant dinosaurs to survive."
The giant pterosaurs of 100 million years ago could not fly today because the atmosphere is too thin, he believes. Much less power is needed to fly at greater atmospheric pressures.
"Today's South American condors -- with their 12-foot wingspans and 25-pound weight -- are the largest creatures that can support and propel themselves through the air according to basic aerodynamic principals," he said. "The pterosaur quetzalcoatlus had a wingspan of more than 45 feet -- half that of a Boeing 737 -- and weighed more than 150 pounds.
"Either it couldn't fly -- but it did -- or the atmosphere had to be much denser at the time," Levenspiel said.
keithtoo ~
There HAD to be a different gravitational environment when gigantism was rampant. I do not believe that bones muscles and tendons in our current gravity could support animals this big. _Jim ~ How about an 'atmospheric density' change (e.g., 30% or twice the density that we have now)?
That would also explain how giant insects would get enough oxygen with their poor circulatory and respiratory systems.
Not only is there a random large scale blasting of the atmosphere into space by occasional giant meteor strikes, the atmosphere is continuously being blown off into space an atom at a time by solar wind and heat.
Over a couple billion years it adds up...