Prof: CO2 levels have been higher

With American living rooms increasingly abuzz with talk of global warming thanks to Al Gore, it has become increasingly important for people, especially students, to know which truths are inconveniently missing from the public forum.

Tomorrow, the United Nation's Intergovernmental Panel on Climate Change will likely report, in a nutshell, that temperatures and sea levels are rising because of human activity.

The discovery of an icy peninsula-turned-island off of Greenland due to melting glaciers and the president's nod to "the serious challenge of global climate change" in his State of the Union address last week pay credence to what a vast majority of scientists have been saying for a while: Global warming is real.

While the Bulletin of Atomic Scientists cited climate change when it recently moved its "doomsday clock" two minutes closer to midnight, scientists who study the ancient past and who agree with global warming also disagree with its oversimplification.

Amy Frappier is one such scientist.

As an assistant professor of geology and geophysics here at Boston College who specializes in the study of ancient climate, known as paleoclimatology, she knows better than anyone that higher levels of carbon dioxide - the chief culprit behind the earth's warming - have also been present in much frostier periods.

"The geologic record shows that many millions of years ago, CO2 levels were indeed higher - in some cases many times higher - than today," said Frappier.

Go back 550 million years, she said, when volcanoes began spewing incredible amounts of carbon dioxide into the atmosphere of a "snowball earth." As the planet gradually warmed, exposing its oceans and land, defrosted chemical broths then used the carbon dioxide to, in essence, evolve into incipient sea creatures like flat worms.

Scientists have found that these ancient forebears contained concentrations of carbon dioxide up to 18 times that of today, according to The New York Times.

A much colder earth had much higher levels of carbon dioxide.

This seeming paradox does not forgive relentless industrialization, said Frappier. But it does complicate the issue for people concerned with the ancient past and its relation to modernity.

"Knowing that very high concentrations of CO2 existed so long ago when geography was very different does not lead to the conclusion that current global warming is necessarily a natural or a good thing," said Frappier. "It is a well established scientific fact that human activities are driving the rise in greenhouse gasses."

"One camp [of scientists] is saying, we're increasing carbon dioxide at a very, very fast rate, and we're seeing warming with that; on the other hand, other guys are saying that hundreds of millions of years ago, we may not see a one-to-one ratio," she said. "There's still some debate about what was going on back then."

In 1992 a research team from the University of New Mexico found carbon dioxide levels 16 times higher than today in soil samples from 440 million years ago, a period of extensive glaciation, according to the journal Nature.

That same science journal also reported a Canadian scientist who discovered extremely high carbon dioxide levels during the ice ages 440 million and 150 million years ago.

These findings discredit the one-to-one ratio that faults humans, and Robert Giegengack, a geologist at the University of Pennsylvania, agreed. "People come to me and say, 'Stop talking like this, you're hurting the cause,'" he said in an interview with The Times, adding that oscillating carbon dioxide levels do not harmonize with the earth's historical hot and cold periods.

Frappier and many of her contemporaries see logic in the dissenting camp's argument, but reason that higher levels of carbon dioxide in antiquity could not fry the planet anyway.

Back then, Frappier said, "the sun was 30 percent as bright - 70 percent dimmer." The absence of complex life "to stabilize climate" also contributed to "rapid flips" when carbon dioxide levels would "lag between" temperature shifts.

As far as carbon dioxide itself is concerned, "at some point the heat-trapping capacity of [the gas] and its effect get saturated," said Frappier, "and you don't have increased heating." In other words, the gas can't trap heat indefinitely since its capacity to do so eventually plateaus.

Frappier also pointed to the Cretaceous period - the dinosaurs' heyday - as "one of the warmest periods with high CO2 levels" as an example of an epoch with complex life and a carbon-dioxide-to-temperature ratio closer to one-to-one.

Before those reptilian beasts, though, Frappier noted the split of pangea around 200 million years ago as another factor.

As subcontinents diverged and usurped the ocean's ancient realm, they altered the earth's capacity to absorb heat. Since "water, [more so than land], has a vast capacity for absorbing heat," the earth absorbed less heat and reflected more as land replaced water near the poles, making it easier to form glaciers that cannot mix with water to continually dissipate the heat throughout the ocean.

Although Frappier says "the science in [Al Gore's Inconvenient Truth] is spot on and excellently presented," the movie fails to mention any ancient incongruity between carbon dioxide and temperature, and in Monday's Heights, Andrew Buttaro claimed in his opinion piece that "analysis of polar ice (which acts as a giant sponge trapping in atmospheric conditions) reveals higher levels of carbon dioxide in the air today than ever before."

"Mr. Buttaro [did] indeed overstate the case that CO2 levels have never been higher," said Frappier. "[He] would have been right to say that CO2 concentrations today are higher than at any time since the evolution of our species … Analysis of polar ice has shown that CO2 concentrations are higher today than at any time in the last 700,000 years."