Two-phase change in CO2, Antarctic temperature and global climate during Termination II

• Published in: Nature geoscience Vol. 6; no. 12; pp. 1062 - 1065
• Main Authors: Landais, A., Dreyfus, G., Capron, E., Jouzel, J., Masson-Delmotte, V., Roche, D. M., Prié, F., Caillon, N., Chappellaz, J., Leuenberger, M., Lourantou, A., Parrenin, F., Raynaud, D., Teste, G.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2013; Nature Publishing Group
• Subjects: 704/106/125; 704/106/413; Age differences; Atmospheric temperature; Carbon dioxide; Climate change; Climatology; Earth science; Earth Sciences; Earth System Sciences; Geochemistry; Geology; Geophysics/Geodesy; Glaciology; Global climate; Hydrologic cycle; Hydrology; Oceans; Sciences of the Universe; France; United States > US; Antarctica
• ISSN: 1752-0894; 1752-0908
• DOI: 10.1038/ngeo1985

The end of the Last Glacial Maximum (Termination I), roughly 20 thousand years ago (ka), was marked by cooling in the Northern Hemisphere, a weakening of the Asian monsoon, a rise in atmospheric CO 2 concentrations and warming over Antarctica. The sequence of events associated with the previous glacial–interglacial transition (Termination II), roughly 136 ka, is less well constrained. Here we present high-resolution records of atmospheric CO 2 concentrations and isotopic composition of N 2 —an atmospheric temperature proxy—from air bubbles in the EPICA Dome C ice core that span Termination II. We find that atmospheric CO 2 concentrations and Antarctic temperature started increasing in phase around 136 ka, but in a second phase of Termination II, from 130.5 to 129 ka, the rise in atmospheric CO 2 concentrations lagged that of Antarctic temperature unequivocally. We suggest that during this second phase, the intensification of the low-latitude hydrological cycle resulted in the development of a CO 2 sink, which counteracted the CO 2 outgassing from the Southern Hemisphere oceans over this period. Glacial Termination II was marked by a rise in atmospheric CO 2 concentrations and global temperature. An analysis of air bubbles from an Antarctic ice core suggests that during the first phase of deglaciation, Antarctic temperature and atmospheric CO 2 concentrations increased together, whereas CO 2 lagged behind temperature rise during the second phase.