Suggested explanations for the discrepancy include that "variations in fossil abundance through time skewed Vrba's data, creating a false peak" or that the "Turkana rift valley—which held a river bounded by woodland at this time—was buffered from the dramatic climatic shifts".
The proposed explanations for the discrepancy are: either variations in fossil abundance over time skewed Vrba's data, resulting in a false peak, or that the Turkana rift valley, which had a river and woodland at that time, was shielded from the significant climatic shifts.