New paper finds CO2 rapidly increased during the last ice age

A paper published today in Geophysical Research Letters finds there was an "Abrupt change in atmospheric CO2 during the last ice age" which occurred "rapidly, over less than two centuries. This rise in CO2 was synchronous with, or slightly later than, a rapid increase of Antarctic temperature." The authors also report "carbon cycle modeling doesn't capture all of the processes for CO2 variations." Thus, rapid increases in atmospheric CO2 have been shown to occur naturally due to processes not captured by climate models. In addition, temperature rise during the last ice age was found to be synchronous or leading CO2 rise, implying that temperature controls atmospheric CO2, rather than CO2 controlling temperature. 

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GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2012GL053018

Abrupt change in atmospheric CO2 during the last ice age

Key Points

• Half of CO2 increase during a 1500-year cold period occurred in < 200 yrs.
• Abrupt CO2 rise is synchronous, or slightly later than,a rapid Antarctic warming.
• Carbon-cycle-climate modeling doesn't capture all of the processes for CO2 variations.

Authors:

Jinho Ahn

Edward Brook

Andreas Schmittner

Karl J Kreutz

During the last glacial period atmospheric carbon dioxide and temperature in Antarctica varied in a similar fashion on millennial time scales, but previous work indicates that these changes were gradual. In a detailed analysis of one event we now find that approximately half of the CO2 increase that occurred during the 1500-year cold period between Dansgaard-Oeschger (DO) events 8 and 9 happened rapidly, over less than two centuries. This rise in CO2 was synchronous with, or slightly later than, a rapid increase of Antarctic temperature inferred from stable isotopes.