Study confirms strong link between CO2 and climate over 70,000 years
September 11, 2008
Comparing records of carbon dioxide concentrations, Antarctic surface temperatures, and Greenland's climate between 20,000 and 90,000 years ago, Jinho Ahn and Edward J. Brook found a close link between past climate change and CO2 levels. The researchers say the findings "appear to confirm the validity of the types of computer models that are used to project a warmer climate in the future," according to a statement from Oregon State University.
"We've identified a consistent and coherent pattern of carbon dioxide fluctuations from the past and are able to observe the correlation of this to temperature in the northern and southern hemispheres," said Ed Brook, an associate professor of geosciences at Oregon State University. "This is a global, interconnected system of ocean and atmosphere, and data like these help us better understand how it works."
"Before humans were affecting the Earth, what we are finding is regular warm and cold cycles, which both began and ended fairly abruptly," Brook explained. "This study supports the theory that a key driver in all this is ocean currents and circulation patterns, which create different patterns of warm and cold climates depending on the strength of various parts of the global ocean circulation system."
"In every historic sequence we observed, the abrupt warming of Greenland occurred about when carbon dioxide was at maximum levels," Brook continued. "And that was during an Ice Age, and at levels of atmospheric carbon dioxide that are far lower than those we have today."
Jinho Ahn* and Edward J. Brook. Atmospheric CO2 and Climate on Millennial Time Scales During the Last Glacial Period. SCIENCE 11 September 2008.