On the Cause of the Mid?Pleistocene Transition

The Mid-Pleistocene Transition (MPT), where the Pleistocene glacial cycles changed from 41 to ?100 kyr periodicity, is one of most intriguing unsolved issues in field paleoclimatology. Over course over four decades research, several different physical mechanisms have been proposed explain MPT, involving non-linear feedbacks between ice sheets and global climate, solid Earth, ocean circulation, carbon cycle. Here, we review these mechanisms, comparing how each them relates others, currently available observational evidence. Based on this discussion, identify important gaps our current understanding MPT. We discuss new model experiments, which focus quantitative differences could help fill gaps. results those experiments interpret proxy evidence, as well evidence that expected become available.