Early Migrations from Africa and the
Mt. Toba Catastrophe

The first migrations of modern humans from Africa were complete failures.*

There were probably many early migrations out of Africa - Misliya, Qafzeh, Es-Skhul, Jebel Faya, and others yet undiscovered - but they all eventually failed. The extremely severe Weichselian ice age and the Mt. Toba eruption exterminated all the earlier migrants. They left fossils and archaeological sites, but no descendants except a few hybrid Neanderthals, Denisovans and a few Homo erectus.

Beginning about 200,000 years ago small groups of Idaltu type people - Haplogroups A, A1, and A1b - began to find a way out of Africa. They moved out on the northern route across the Sinai as suggested by the "Sahara Pump Theory". The warm, moist conditions of "Abbassia Pluvial" type climate periods made that area much less formidible than it is today. It is not known whether the climate changes triggered the movements or just made it possible. These small migrations continued for at least 130,000 years. They spread to India and on to southeast Asia by 80,000 years ago.

The competition and the struggle for survival may have been fierce and deadly. The space they were moving into was occupied by several varieties of genus Homo entrenched there, in some cases, for more than a million years. Homo Erectus still thrived, as did Heidelbergensis, Neanderthals, and Denisovans. These were all serious competition.

Mega-fauna as food sources included: woolly mammoth, steppe mammoth, straight-tusked elephant, aurochs, steppe bison, Irish elk, equus, and Elasmotherium, but these are all large and dangerous to hunt with just primitive weapons such as spears and clubs.

There were many hazards including dangerous predators that hunted the migrants. These included: wolf, cave lion, cave bear, cave hyena, saber-toothed tigers, and giant polar bears among others. Other hazards included a new assortment of deadly germs, poisonous plants, and insects.

Life for these pioneers would never have been easy
and then things got very much worse
75,000 y.a. __The Mount Toba eruption was the largest volcanic eruption of the last 25 million years.
Mt. Toba
A vast amount of ash and noxious gases (six gigatons of sulfur dioxide and 3,000 cubic kilometers of rock) were emitted, causing extinctions of food sources and decades of famine. It was also a significant contributor to the thousand year long cold period that followed.

It caused extinction of Homo sapiens outside of Africa. The number of humans was reduced to a very small population of between 1,000 and 10,000 breeding pairs, total, worldwide. The population reduction did not happen instantanously. Most of the few survivors were scattered from Ethiopia to southern Asia at an average population density less than one person per mile. Many surviving groups were well below the population threshhold necessary to survive in the ordinary course of events. Maintaining a tribal life and finding mates would have been very difficult, inbreeding would have been rife, so they slowly went extinct.

One ironic effect was that predators and competitors were also very much reduced, allowing the following "Out of Africa"* migration to be resoundingly successful. Haplogroup CT, migrating from Africa, found itself to be the new 'Top Predator' in the new low-competition environment of southwest Asia. Repopulation of Asia and Europe began with the descendants of Haplogroup CT.*

* That is the "Out of Africa" theory or "Recent African Origins (RAO)" hypothesis. One of the many varied counterclaims is that some groups in southeast Asia, upwind of Mt. Toba, survived and that from there a migration to the west resulted in the modern human population of Europe and Asia and of Haplogroup E in Africa. This could be called the "Out of Indochina" model. Another is that survivors everywhere all simultaneously evolved into H. sapiens. It is called the "Multiregional" model. There are other models. This is a subject of heated argument.