26 Paleoclimatology/Paleoceanography (Posters)

Sunday, 4 November 2012
9:00 AM - 6:30 PM
Hall B

A HIGH RESOLUTION CARBON DIOXIDE RECORD FOR THE LAST DEGLACIATION FROM THE WAIS DIVIDE ICE CORE

Paper number: 26-10
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Establishing the role of carbon dioxide, both as a feedback and forcing, during the most recent deglaciation provides the best opportunity to understand the relationship between the carbon cycle, ice sheets, and global temperatures. This requires a precise, high-resolution, well dated record of atmospheric CO2. Existing Antarctic ice core records have provided insight into both the timing of CO2 changes and likely sources, but lack the temporal resolution to address some important problems. CO2 data from the WAIS Divide ice core will yield the highest resolution and best dated CO2 record covering the last ~60 ka, due to the high accumulation rate at the site (presently 20 cm/yr) and excellent chronological control from layer counting and high resolution correlations to well dated ice core and other climate records.

Here we present a CO2 record from the WAIS Divide Ice Core (WDC) in Antarctica for the period 25,000 – 8,000 years BP. Our record is in excellent agreement with previous reconstructions of CO2 during the last 20,000 years after accounting for temporal smoothing of those other records due to diffusion in the firn. However, several abrupt changes in CO2 occur in the WDC record that have not been fully documented elsewhere. Several of these abrupt CO2 changes occur synchronously with changes in CH4 at key climate transitions, including an abrupt CO2 increases during Heinrich stadial 1, the onset of the aBølling-Allerød, and end of the Younger Dryas. CO2 rise in the WDC occurs at ~18 ka on our newest chronology. Owing to the small delta-age and excellent chronologic constraints for the WDC, CO2 variability can now be documented at the centennial or shorter time scale. Thus, the timing and amplitude of abrupt changes in CO2 is very precisely resolved, which has allowed for the most well constrained greenhouse gas record to date.