This piece is my critical response to the article Toba Super Eruption: More bang than an apocalyptic ash cloud? By Shaun Smillie
The original article appeared on the Daily Maverick, a South African news platform. While a number of articles have recently covered the discovery that the aftermath of the Lake Toba supervolcano 74,000 years ago was not a cataclysm for South Africa, there were a few interesting details in this piece which made it stand out as worth a detailed reply. I challenge the assumptions of the investigating scientists and highlight a number of obvious solutions to anomalies in the data.
“It might have been the closest brush our species had with extinction and we have no memory of this trauma.”
The belief that Lake Toba almost brought humanity to extinction is becoming less supported, it rather seems that we already had low population levels due to a bottleneck event closer to 130,000 years ago and that the bottleneck event recorded in the non-African genome relates to the ancestral migration of only a small number of people (some estimates suggest 200 individuals) around 60,000 years ago.
“For six long years small bands of humans clung to survival as the earth froze and ash blotted out the sun. With no sunlight, most of the planet’s plant life had died off.”
Paleoclimate models suggest that the ejecta (both the dust and gas) moved rapidly to the northwest. This deadly cloud of debris enveloped the northern hemisphere of the planet bringing about the scenario described above. The climate impact would have been rather negligible for the sub-equatorial regions. This all occurred as the planet was entering a cooling phase and inevitably the supervolcano accelerated the climate shift.
“What was left were just a few thousand humans who survived in isolated pockets across southern Africa. Later, after their populations had recovered sufficiently, these pioneers headed out of Africa and repopulated the rest of the world.”
As mentioned previously it now seems there was already a low effective global population, it is hard to know how much further Toba lowered the numbers of Homo sapiens. What must be contested here is that all of these early humans were in Southern Africa, this goes against the archaeological evidence. We have pre-Toba modern human’s fossils and tools associated with our sub-species distributed across the Levant, China, Indonesia and potentially Australia (dating uncertainties). The bulk of the existing genetic and physical evidence now runs directly counters the popular consensus hypothesis that post-Toba an African founder population went on to repopulate the world beyond. I will explain this below.
“Researchers from the University of Arizona who studied sediment cores taken from Lake Malawi, believe they found no evidence of a plant die off that would have come with the six-year long nuclear winter, that is proposed to have happened in the Toba catastrophe theory.”
This only confirms what should have been assumed right from the moment the paleoclimate models revealed that only the Northern Hemisphere would have suffered a nuclear winter. It should have been no surprise to find that sub-equatorial regions were only moderately affected.
““All non-African populations have a bottleneck during this time but it is most probably due to the migration out of Africa. Toba might have added to this bottleneck – but we just don’t know,” says Geneticist Assistant Professor Carina Schlebusch, of the Uppsala University in Sweden, adding she wants to see more evidence.”
The Lake Toba eruption at 74,000 years, is so close to the time that Eurasia was [re]populated, approx 60,000 years ago, that it is easy to see how the margin of error would allow the event to be confused with the bottleneck caused by migration into Eurasia. Consider that one leading geneticist calculates that the migrating population numbered only around 200 effective individuals. Again, we should be hesitant to accept that this repopulation has its source in Africa (I am still coming to that).
“Archaeologists also lament that there is not enough evidence in the archaeological record to tell just what was happening at around 74,000 years ago.”
I communicated with the geologists involved in the new research and they confirmed that little useful data available on the full impact the Toba eruption had on hominins (including modern humans) living in the Northern Hemisphere. We can certainly infer that they had a bad time because by the time Eurasia was repopulated the continent was almost empty and within about 20,000 years of the migration starting there were no other hominins remaining on the continent.
““However, they then argue that this environmental impact was not significant enough to impact human populations. I think this interpretation is unjustified because they do not present any archaeological evidence for how human populations reacted to this environmental change. The archaeological evidence is required,” Marean says.”
This is especially relevant when we consider my above comment on the lack of any sustained efforts to understand what was happening to humans in Eurasia. We also know that humans were living in North Africa and the Levant prior to Toba, so what about these people?
The conviction that human populations were not impacted significantly is best on the invalid assumption that all Homo sapiens lived in Sub-Saharan Africa at the time of the eruption. We have archaeology placing modern humans in the Levant, Middle East, India, China, Indonesia and Australia prior to the Toba eruption. The Dali skull places archaic Homo sapiens in China 260,000 years ago, but most of the additional evidence is associated with the period 80,000 – 120,000-years ago.
“It was time when these early humans went through a bit of a renaissance. They began decorating themselves, beads, manufactured poisons and developed bow and arrows.
With these new technologies they began their long march out of Africa.”
This sudden technological and cultural change indeed advancement, should be a red flag that something else is going on here. If sub-equatorial Africa is not being impacted by the Toba event, or in a minor way only, what is the tenuous link between a perhaps a very slight cooling of the climate and such a radical shift in human culture?
It sounds almost as though somebody has arrived that had a very different culture involving body adornment, unique plant knowledge and highly advanced weaponry. This sounds like cultural diffusion, not a renaissance.
Why would these people safe in Sub-Equatorial Africa now move northwards into a cataclysmic climate and environment?
Three recent climate studies have deduced that from 73,000 – 59,000 years ago, North Africa, the Levant and the Middle East were deep in the most extreme drought yet detected in those regions. Any attempt to exit Africa by land would have been a suicide mission, and one must wonder what is the driving force that makes humans leave green pastures for barren wastelands. It is not reasonable and illogical; therefore, the default assumption should be that it did not occur and so far no solid evidence is found suggesting it did.
“In the human genetic record, this movement might explain that bottleneck.
It is known as the founder effect, where a smaller group of individuals break from a larger population, and this causes a loss in genetic variation.”
Now we come to the most important part of this discussion, analysis of the genetic record and the divergence of a founder population responsible for repopulating Eurasia. Every genetic study I have looked at dates the start of the populating of Eurasia at between 60,000 – 50,000 years ago, with a strong pull towards 55,000 years ago. I have never encountered a study that dates the divergence of the first Eurasians to anywhere around 70,000 years ago – that earlier date is always given for reasons of dogma associated with existing consensus and is not supported by DNA analysis.
We certainly do see a founder effect going on with respect to Eurasians after the migration begins 60,000 years ago, with leading geneticists suggesting as few as 200 individuals acted as the ancestors for all living Eurasian people this reduction in genetic diversity is hardly surprising. What is more surprising perhaps is the specific basal lineages associated with modern Eurasians and that they are not known to have ever been in Africa.
The haplogroups we need to look at are mtDNA HgM and HgN, as well as Y-chromosomal HgCT, because all Eurasians trace back to these, but they are understood to have never been carried by African populations. This is problematic, the workaround is to assume HgM and HgN are the results of mutations which occurred in a population of East Africans carrying the closely related HgL3 lineage.
““So the key is to look at what happens in African populations. So far it does seem that at least some African populations show at least mild bottlenecks during this time, not at all as drastic as the old theory of only few thousand humans surviving, but there seems to be something going on,” says Schlebusch.”
Here is where things get very interesting because when we look at what is happening in Africa around 73,000 years ago we see the sudden appearance of the mtDNA haplogroup L3 and Y-chromosomal haplogroup CT. They appear in East Africa first and then spread westwards and southwards over time – entirely the wrong direction for people moving out of the continent and the origin seems to be close to the Bab-el-Mandab Straits (an easy crossing in that era of low sea-level). This happens while Eurasians are almost certainly being driven to extinction by a nuclear winter. Their best hope for survival is to find a refuge south of the equator.
There is a very specific problem with the emergence of a new MtDNA lineage at the same moment as a new Y-Chromosomal lineage – the mutation rates are different by a factor of 10. There is little to no chance such new lineages would appear in the same small region at the same moment due to a mutation event.
Now when we also factor in the sudden cultural changes and appearance of new more advanced science and technology it becomes glaringly obvious we are tracking a small group of climate refugees that have fled from Eurasia (and with their poison arrows and all hell raging at their backs I am betting no hominins of any species in Africa could have stopped them).
““The only thing that is going to get us closer to understanding this is a genetic resolution, because we can’t excavate everything. It is the genes that will show us whether there was a bottleneck or not,” says Lombard.
Then we might just rediscover what was perhaps our darkest hour, that we all have but forgotten about.”
It is indeed in the genetics that we find the final revelations in this story. You will recall that scientists argue that perhaps haplogroup L3 emerged in Africa and then some of these people migrated out of the continent almost immediately (approx. 70,000 years ago) at which time their genome then spontaneously produced two new sudden mutations. This is again without any explanation and against all normal process and gives us the Eurasian basal haplogroups HgM and HgN. This assumption is based only on the fact that these two ‘new’ haplogroups very closely relate to HgL3, while HgL3 is the most divergent mtDNA lineage in Africa (very different to African lineages L1, L2, L4, L5 and L6).
So, if this very strange event really happened at all then we should see the traces of the oldest variants of Haplogroups M & N in the genome of people close to Africa, in the Middle East or Western Asia. In the most recent study that looked at this what they discovered was that the oldest variants of HgM and HgN are found on the other side of the planet within the genome of Australian Aboriginals!
This problematic finding comes on top of several others in the last two years, these include the discovery of archaeological sites in Australia in the 65,000 – 80,000-year range, the divergence of Australian DNA from any African DNA by at least 72,000 years ago. These issues created enormous anomalies, then followed the collapse of both the rapid Asian coastal migration theory and the multiple waves theory (both being desperate attempts to explain how Aboriginals could be in Australia earlier than 50,000 years ago).
The ancestors of modern Eurasians can’t be just leaving Africa close to 60,000 years ago, and then be immediately on the far side of the planet or arrive there before they left. They also can’t have left Africa before 73,000 years ago, because the appearance of HgL3 in East Africa is the only tenuous piece of data that can link the first Eurasians to Africa at all (even then as we have seen it is the weakest of threads). Recently we have seen media channels propping up the dishonest academics who are now suggesting the migration began significantly earlier than 80,000 years ago. There is not one fossil, genome or piece of climate data that can support that claim – it is no more than a band-aid being used to save face for a great many ‘Recent Out of Africa’ academics.
Keep in mind here that there is no ancient African fossil that produced DNA from which a solid link can be established, the oldest DNA sample ever recovered from an African bone is no more than 8000 years old. The recent out of Africa theory is not even based on that sample but on the DNA of 20th century Africans, with the massive assumption their ancestors were all and always in Africa (based on the fact that when the theory was founded we only had African human fossils).
The fact is that all living Eurasians can trace their lineages back to HgM and HgN, not to HgL3. The archaeological and genetic data all support repopulation of Eurasia post-Toba at 60,000 years ago, from East to West. These migrants finally reached Europe, the Levant and North Africa around 45,000 years ago. The founder population involved here was never the Africans and always the Australian Aboriginals. We now have conclusive archaeology, genetics and climate data to displace the current consensus model.