|Title:||High Resolution CO2 Reconstructions from the WAIS Divide Ice Core|
|Author:||Marcott, S.A., Bauska, T.K., Sowers, T.A., Edwards, J.A., Buizert, C., Kalk, M. and Brook, E.|
|Periodical:||American Geophysical Union, Fall Meeting 2013, abstract #PP21E-02|
A clear connection exists between atmospheric greenhouse gases, climate, and ice sheet volume during glacial-interglacial cycles. Establishing the role of carbon dioxide (CO2), both as a feedback and forcing, during the most recent glacial and deglacial periods provides an excellent opportunity for understanding how this connection operates. To do this, a precise, high-resolution, well-dated record of atmospheric CO2 is a prerequisite. We will present a carbon dioxide record from 40-35 and 28-9 ka from the last glacial and deglacial periods from a new ice core from West Antarctica with an average sampling resolution of 25-50 yrs. Our record shows that CO2 variations during the glacial period have a clear relationship with abrupt climate changes in the Northern Hemisphere that continues into the deglacial period. In addition, instead of being gradual (several millennia), nearly half of the ~85ppm rise in CO2 during the deglaciation occurred in three abrupt 10-15ppm steps that took place in less than 100-200 yrs and were followed by concentration plateaus. Each transition was synchronous with abrupt changes in methane (CH4), suggesting a rapid reorganization of the carbon cycle. These rapid changes in atmospheric CO2 and CH4 concentrations are also recorded during the Heinrich Stadials of MIS 3, demonstrating an important mechanism that operates on centennial time scales during the glacial and deglaciation, which may point to important thresholds in the global carbon cycle. We will present our most recent results and newest interpretation.