PP026. Orbital Forcing of Climate and the mid-Pleistocene Transition
Climate archives, based on records of oxygen isotopes from marine sediments, show a pronounced change in the periodicity of the glacial cycles during the mid-Pleistocene (~1 million years ago). Before this time, and possibly from the initiation of major glaciations, the periodicity is dominated by the 41 kyr obliquity cycle of orbital insolation. However, in the past million years the ~21 and ~100 kyr cycles of precession and eccentricity have dominated the records of glacial cycles, and the records of atmospheric greenhouse gasses.
This climate transition, the mid-Pleistocene Transition (MPT), is not fully understood. Nor are the dynamics of the glacial cycles. In this session we welcome contributions with perspectives on the MPT as well as the dynamics of the glacial cycles based on proxy records, theory and models. The topic is also timely in light of ongoing efforts to extract a continuous Antarctic ice core record spanning the MPT.