Megafauna Extinctions

This paper presents a systems-level framework for understanding late Pleistocene megafauna extinctions across the Americas and other regions. Rather than treating extinction as the result of a single dominant cause, it argues that the observed geographic asymmetry, delayed extinctions, and selective survival patterns are best explained by the interaction of multiple pressures operating over extended timescales.

The analysis integrates climatic instability, atmospheric circulation shifts, Northern and Southern Hemisphere glaciation, habitat fragmentation, vegetation collapse mechanisms (including snowpack loss and deep soil freezing), ecological feedbacks, and sustained human presence. Particular emphasis is placed on the role of glacial climate geometry in creating regional refugia and on the transient productivity of post-glacial ecosystems that differed materially from modern landscapes.

The paper reframes the longstanding climate-versus-overkill debate as a false dichotomy and instead characterizes megafauna extinction as a cumulative, threshold-driven systems collapse. The intent is not to replace existing models, but to provide a coherent synthesis that accounts for spatial and temporal complexity in the extinction record.