Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: MONDAY, June 14, 1993 TAG: 9306140039
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: By MICHAEL CSOLLANY STAFF WRITER
DATELINE: LENGTH: Medium
McLean, a professor of paleontology at Virginia Tech, has one of the two leading scientific theories on what caused the demise of the prehistoric giants.
He also warns that if humans aren't careful, we could duplicate the conditions he contends did in the dinosaurs.
Switching from a light-hearted interview mode to a college-lecture mode, McLean says that volcanic disturbances 65 million years ago sent large amounts of carbon dioxide into the atmosphere. This carbon dioxide allowed sunlight to pass through the Earth's atmosphere, but retained the heat, creating a rapid greenhouse effect.
McLean gets up from his seat and draws a diagram on the blackboard -- almost second-nature for the veteran teacher who has sometimes likened himself to the creatures he studies.
The greenhouse condition is like the one the Earth faces today from the burning of fossil fuels, albeit much faster, he says.
As proof of his theory, McLean says that 500,000 square kilometers of lava still exist in India after millions of years of erosion.
He gives a globe a twirl to show the area in Western India where lava exists.
"In addition, we have all kinds of evidence that the Earth heated up at the time," he says. He says that large amounts of carbon were found that were deposited 65 million years ago, suggesting a rapid increase in carbon dioxide at the time.
McLean also notes research that ties increases in heat to disruption of the female reproductive process. "Rapid climatic changes are very dangerous to life. . . . Heat reduces the flow of blood into the female uterine track, damaging and killing embryos," he says.
Was this research that McLean happened upon in the library or the laboratory? Nope. McLean says he learned of it in his garden from Tech associate and next-door neighbor Frank Gwazdauskas, who has done research on heat and dairy cows.
Humans managed to survive the last major extinction 11,000 years ago, but McLean says we might not be so lucky the next time: "If we experience a major greenhouse, modern mammals will not get through it unscathed." McLean has addressed the Senate on greenhouse conditions.
McLean's hypothesis contradicts the asteroid theory. "By that idea, a large rock about six miles in diameter slammed into the Earth 65 million years ago, creating such a huge explosion that the dust from the explosion blocked out sunlight," McLean explains.
He believes there is no substantial evidence for this theory. "There is no evidence in the rock record of blacking out or freezing in the Earth around the time of the dinosaur extinction," McLean says, shaking his head.
He notes that his opposition almost cost him his career. The asteroid theory, he says, has many interests supporting it.
"Politics have become more important than data in influencing public and scientific opinion," he says. The asteroid theory is the basis for the multimillion-dollar "Spacewatch" program, which seeks to destroy asteroids potentially on a collision course with the Earth.
McLean believes the extinction debate issue has fueled some of the recent popular interest in dinosaurs.
"Because of this debate, hardly a week goes by when there aren't television shows, television series, books and newspaper articles about dinosaurs. The public is always reading about dinosaurs. The public is simply saturated with the dinosaurs."
It is one of the top 10 or 20 greatest scientific mysteries, he says.
"The dinosaurs had lived successfully for 140 million years. They were huge beasts, seemingly invulnerable. They're exotic. They're alien to our senses. Many of them are large and bizarre-looking," McLean says, noting the creatures' potential for curiosity.
And does McLean think the events of "Jurassic Park" are possible?
"I talked to one of our geneticists here at Tech, Joseph Falkinham, and asked him if it is possible to get ancient DNA and recreate creatures in the past," McLean says. Falkinham said that it could be possible in 50 years.
"What is often is fabulation today is fact in the future," he says.
"Fabulation," one of McLean's favorite words from a book of lyrics, is defined as "an idea somewhere between the possible of the romantic and the incredible of the fantastic."
"But I don't know why anyone would want to [bring back the dinosaurs] . . . Introducing an alien entity into a balanced or quasi-balanced world could wreck havoc," McLean says.
Godzilla roaming through the streets of Blacksburg is just not an appealing thought for the professor.
by CNB