160,000 yr. BP - 12,000 yr BP [red vertical bar]


The span of time since modern man first appeared upon Earth is uncertain. The trend in scholarship, as with most other matters pertaining to the times of old, is towards an ever increasing antiquity. The oldest apparently modern human skeletal remains have been found in Ethiopia and in the Middle East. They have been dated as old as 160,000 years and have been christened Homo Sapiens Idaltu, assumed to be a sub-species Homo Sapiens and the immediate predecessor of Homo Sapiens Sapiens, with one of the main distinguishing characteristics between them and us, so to speak, being a larger cranium. Whether a 1450 cc brain capacity implies greater intelligence than moderns is impossible to determine at this point, but, if one accepts the legitimacy of Homo Idaltu as a modern human, at least insofar as raw intelligence is concerned, it places the presence of mankind back at least 160,000 years. How much older we go remains to be seen. New finds may push that date back another 30,000 years.

The purpose of this chart is to portray the extent to which major climate and environmental changes have transpired on Earth during the time that modern man has existed. It does not presume to completeness, and, no doubt, additional events will be added as more research becomes available. Also, the exact timing of many of these events is still being debated. This chart will be updated as new and more precise knowledge becomes available. However, the major implication is already quite obvious, and that is that profound climatic and environmental changes have occurred repeatedly during the course of Man’s tenure on Earth. While most of these changes are not yet fully understood, what is clear is that a repetition of any of the events depicted in this chart could, or would, impose severe stress on modern society, even to the extent of inaugurating a new dark age, if not effectively terminating civilization altogether.

12,000 yr. BP - Present [blue vertical bar]


The Holocene is the most recent of geological epochs, the one in which generally modern environmental conditions have prevailed. It was preceded by the epoch known as the Pleistocene which was characterized by a succession of glacial ages in which massive amounts of ice waxed and waned over the surface of the Earth. The Pleistocene is generally considered to have lasted for about 2 million years.


It is questionable whether the Holocene constitutes a truly distinct epoch or is instead merely a temporary interglacial hiatus within the Pleistocene. In any case, what generally defines the termination of the Pleistocene is the abrupt disappearance of scores of large mammal species the world over. The cause of this extinction event is controversial, with human predation generally being the leading contender among paleontologists. However, given the unambiguous data pointing to catastrophic climate changes at the transition from the Pleistocene to the Holocene Epoch, that appears to have coincided precisely with the extinction, it would appear increasingly untenable that a human role played a significant part, if any part at all, in the disappearance of the megafauna.


It is within the Holocene that the historical record begins. It now appears certain that the next phase in the understanding of human history and prehistory will evolve as we come to realize the dominant role played by catastrophic, non-anthropogenic climate and environmental change.