Earth's minerals kept CO2 levels in balance prior to humans
April 28, 2008
CO2 emissions are presently 100 times the natural rate
Analyzing atmospheric CO2 levels for the past 610,000 years using data from gas bubbles trapped in Antarctic ice cores, Ken Caldeira of the Carnegie Institution's Department of Global Ecology and Richard Zeebe of the University of Hawaii modeled how carbon dioxide released into the atmosphere from natural sources is "ultimately recycled via carbon-bearing minerals back into the crust," according to a statement from the Carnegie Institution.
"The system is finely in tune," Caldeira told Cutler. "That one or two percent imbalance works out to an average imbalance in natural carbon dioxide emissions that is thousands of times smaller than our current emissions from industry and the destruction of forests."
The researchers note that carbon dioxide is presently being added at about 100 times its historic rate of 0.1 billion tons of carbon each year, or approximately 10 billion tons. Most of these emissions result from human industrial activity and conversion of forests.
"The imbalance in the carbon cycle that we are creating with our emissions is huge compared to the kinds of imbalances seen over the time of the glacial ice core records," Caldeira said. "We are emitting CO2 far too fast to expect mother nature to mop up our mess anytime soon. Continued burning of coal, oil and gas will result in long-term changes to our climate and to ocean chemistry, lasting many thousands of years."