Siple Dome ice reveals two modes of millennial CO2 change during the last ice age.

Jinho Ahn,Edward J Brook

doi:10.1038/ncomms4723

Abstract

Reconstruction of atmospheric CO2 during times of past abrupt climate change may help us better understand climate-carbon cycle feedbacks. Previous ice core studies reveal simultaneous increases in atmospheric CO2 and Antarctic temperature during times when Greenland and the northern hemisphere experienced very long, cold stadial conditions during the last ice age. Whether this relationship extends to all of the numerous stadial events in the Greenland ice core record has not been clear. Here we present a high-resolution record of atmospheric CO2 from the Siple Dome ice core, Antarctica for part of the last ice age. We find that CO2 does not significantly change during the short Greenlandic stadial events, implying that the climate system perturbation that produced the short stadials was not strong enough to substantially alter the carbon cycle.

Highlights

Reconstruction of atmospheric CO2 during times of past abrupt climate change may help us better understand climate-carbon cycle feedbacks
Ice core records from Greenland reveal a detailed history of abrupt climate change during the last glacial period
Atmospheric CO2 change during the short stadials is not well resolved in existing ice core records owing to low temporal data resolution (280–570 years11,12,22)

Summary

Introduction

Reconstruction of atmospheric CO2 during times of past abrupt climate change may help us better understand climate-carbon cycle feedbacks. Existing Antarctic ice core records show CO2 increases during long Greenlandic stadials, which are accompanied by major Antarctic warmings[11,12]. During the long stadials of the last ice age, marine sediment records indicate shoaled AMOC18 and increased opal flux[14] in the Southern Ocean, the chronology of the proxy for the latter is not well constrained.

Results

Conclusion