Separate from their analysis of the climate data, the authors conclusion regarding human evolution is based on the correlation between their climate analyses and a specific human evolutionary model. Given a different model (part E of the figure above), this correlation wouldn’t necessarily exist. And yet this kind of approach, combining information from different (hopefully somewhat independent) lines of evidence to address single hypotheses, is what paleoanthropology is primed for.
He hat tips the "Broadly Consistent Watch" feature here, which I badly need to revive...
- . Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution. Proceedings of the National Academy of Sciences of the United States of America. 2011.