Study finds CO2 didn't end ice age - Counters major premise of global warming theory
September 29, 2007
A new peer-reviewed scientific study counters a major premise of global warming theory, concluding carbon dioxide did not end the last ice age.
The study, led by University of Southern California geologist Lowell Stott, concluded deep-sea temperatures rose 1,300 years before the rise in atmospheric CO2, which would rule out the greenhouse gas as the main agent of the meltdown.
"There has been this continual reference to the correspondence between CO2 and climate change as reflected in ice core records as justification for the role of CO2 in climate change," said Stott. "You can no longer argue that CO2 alone caused the end of the ice ages."
The study will be published in the next issue of Science magazine.
Another new study published in Science refutes the "Hockey Stick" temperature graph, used by man-made global warming theorists such as former Vice President Al Gore to argue for a recent spike in average global temperature after centuries of relative stability.
Stott's new study suggests the rise in greenhouse gas likely was a result of warming. It may have accelerated the meltdown, he says, but was not its main cause.
He cautioned that the study does not discount the role of CO2.
"I don't want anyone to leave thinking that this is evidence that CO2 doesn't affect climate," he said. "It does, but the important point is that CO2 is not the beginning and end of climate change."
Stott's collaborators were Axel Timmermann of the University of Hawaii and Robert Thunell of the University of South Carolina. Stott, an expert in paleoclimatology, was a reviewer for the Intergovernmental Panel on Climate Change, the U.N.-commissioned group that has published reports blaming warming on human sources.
Stott's study found a correlation between melting Antarctic sea ice and increased springtime solar radiation over Antarctica, suggesting this might be the energy source.
The authors' model also showed how changed ocean conditions could have been responsible for the release of CO2 from the ocean into the atmosphere, also accelerating the warming.
The scientists derived their results from a study of a unique sediment core from the western Pacific composed of fossilized surface-dwelling and bottom-dwelling organisms. The organisms incorporate different isotopes of oxygen into their shells depending on the temperature, enabling the researchers to reconstruct deep and surface ocean temperatures over time.
If CO2 caused the warming, surface temperatures should increase before deep-sea temperatures. But the scientists found the water used by the bottom-dwelling organisms began warming about 1,300 years before the water used by the surface-dwelling ones.
"The climate dynamic is much more complex than simply saying that CO2 rises and the temperature warms," Stott said. The complexities "have to be understood in order to appreciate how the climate system has changed in the past and how it will change in the future."