Glacial - Interglacial Climate Oscillations

Pronounced glacial-interglacial cycles have been defining for the climate of the Pleistocene. Paced by its periodically changing orbit, throughout the past 1.8 million years, the Earth has repeatedly undergone advances and retreats of ice sheets in particular in the Northern Hemisphere. Climate reconstructions of the past 1 million years reveal a saw-tooth periodicity with the following cycle of around 100,000 years:

Climate reconstructions of glacial cycles also reveal climate variations on millennial timescales which are particularly prominent in the last glacial period (from ~115,000 - ~11,000 years ago).
Simulating glacial-interglacial and millennial scale climate variations, always using climate reconstructions as a reference, allows us to study the multitude of feedbacks coming into play in a globally changing climate, such as:

  • biogeochemical feedbacks that cause glacial-interglacial variations in atmospheric CO2 from ~180 ppm to ~300 ppm
  • vast northern hemispheric ice sheets that influence the atmospheric circulation and the radiative budget of the Earth
  • substantial amounts of meltwater that influence ocean currents during teminations and millennial climate fluctuations.

Examples from our research:

An, Z., Zhou, W., Zhang, Z., Zhang, X., Liu, Z., Sun, Y., Clemens, S. C., Wu, L., Zhao, J., Shi, Z., Ma, X., Yan, H., Li, G., Cai, Y., Yu, J., Sun, Y., Li, S., Zhang, Y., Stepanek, C., Lohmann, G., Dong, G., Cheng, H., Liu, Y., Jin, Z., Li, T., Hao, Y., Lei, J. and Cai, W. (2024): Mid-pleistocene climate transition triggered by Antarctic Ice Sheet growth, Science, 385(6708), 560–565, doi:10.1126/science.abn4861

Knorr, G. , Barker, S. , Zhang, X. , Lohmann, G. , Gong, X. , Gierz, P. , Stepanek, C. and Stap, L. B. (2021): A salty deep ocean as a prerequisite for glacial termination , Nature Geoscience, 14 , pp. 930-936 . doi: 10.1038/s41561-021-00857-3

Starr, A. , Hall, I. R. , Barker, S. , Rackow, T. , Zhang, X. , Hemming, S. R. , van der Lubbe, H. J. L. , Knorr, G. , Berke, M. A. , Bigg, G. R. , Cartagena-Sierra, A. , Jiménez-Espejo, F. J. , Gong, X. , Gruetzner, J. , Lathika, N. , LeVay, L. J. , Robinson, R. S. and Ziegler, M. (2021): Antarctic icebergs reorganize ocean circulation during Pleistocene glacials , Nature, 589 (7841), pp. 236-241 . doi: 10.1038/s41586-020-03094-7

 

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