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CO? in air grows at a surprising rate

Scientists find the rate rising 35 percent more since 2000 than they expected.

By TIMES WIRES
Published October 23, 2007

WASHINGTON - A new study finds that carbon dioxide in the atmosphere is increasing much faster than expected.

The growth rate for carbon dioxide emissions has averaged 3.3 percent a year since 2000, compared with 1.1 percent in the 1990s, researchers led by Josep Canadell, an Australian-led team of scientists report in today's edition of Proceedings of the National Academy of Sciences.

The rate rose 35 percent more than economic growth had led scientists to anticipate, said Corinne Le Quere, one of the authors of the paper.

Increased industrial use of fossil fuels coupled with a decline in the gas absorbed by the oceans and land were listed as causes of the increase. The changes "characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing," the researchers report.

"Concentrations of CO2 are increasing at much higher rates than previously expected, and this is in spite of the Kyoto Protocol that is designed to hold them down in Western countries," said Kevin Trenberth of the climate analysis section of the National Center for Atmospheric Research in Boulder, Colo.

Alan Robock, associate director of the Center for Environmental Prediction at Rutgers University, added: "What is really shocking is the reduction of the oceanic CO2 sink," meaning the ability of the ocean to absorb carbon dioxide, removing it from the atmosphere.

The researchers blamed that reduction on changes in wind circulation, but Robock said he also thinks rising ocean temperatures reduce the ability to take in the gas.

FAST FACTS

Fossil fuel a major culprit

From 2000 to 2006, carbon released from burning fossil fuel and making cement rose from 7-billion metric tons per year to 8.4-billion metric tons, an increase of 20 percent, according to the study. A metric ton is 2,205 pounds.

Carbon dioxide is the leader among the greenhouse gases, but it's not the whole story, said atnalyst Kevin Trenberth. Methane emissions have declined, so total greenhouse gases are not increasing as much as carbon dioxide alone. Also, he noted, other pollution plays a role by cooling the atmosphere.

[Last modified October 22, 2007, 22:35:35]