Comment (2) on "Formation of the Isthmus of Panama" by O'Dea et al.

O'Dea et al. challenged the inference that the Isthmus of Panama has been in place for the last 10 million years or more and from "an exhaustive review and reanalysis of geological, paleontological, and molecular records," they argued for a "formation of the Isthmus of Panama sensu stricto around 2.8 Ma." I review environmental changes since ~5 Ma throughout Earth, and I argue that environmental changes in the Central American-Caribbean region have been part of a concurrent, worldwide phenomenon that requires a global, not local, explanation. Accordingly, evidence of environmental change from the Central American-Caribbean region does not implicate the emergence of the Isthmus of Panama.