The world’s first and only “climate refugees” – Ancient Africans

It has been argued (unsuccessuly) that the current change in climate will cause millions to billions of “climate refugees”. Some of these claims have been so “over the top” that they were quietly withdrawn and swept under the rug. Here, we have a real case of climate refugees based on natural variation of the climate.

From the UNIVERSITY OF ARIZONA and the “natural variation before the SUV is wot dun it” department:

Ancient humans left Africa to escape drying climate

Humans migrated out of Africa as the climate shifted from wet to very dry about 60,000 years ago, according to research led by a University of Arizona geoscientist.

Genetic research indicates people migrated from Africa into Eurasia between 70,000 and 55,000 years ago. Previous researchers suggested the climate must have been wetter than it is now for people to migrate to Eurasia by crossing the Horn of Africa and the Middle East.

“There’s always been a question about whether climate change had any influence on when our species left Africa,” said Jessica Tierney, UA associate professor of geosciences. “Our data suggest that when most of our species left Africa, it was dry and not wet in northeast Africa.”

Tierney and her colleagues found that around 70,000 years ago, climate in the Horn of Africa shifted from a wet phase called “Green Sahara” to even drier than the region is now. The region also became colder.

The researchers traced the Horn of Africa’s climate 200,000 years into the past by analyzing a core of ocean sediment taken in the western end of the Gulf of Aden. Tierney said before this research there was no record of the climate of northeast Africa back to the time of human migration out of Africa.

“Our data say the migration comes after a big environmental change. Perhaps people left because the environment was deteriorating,” she said. “There was a big shift to dry and that could have been a motivating force for migration.”

“It’s interesting to think about how our ancestors interacted with climate,” she said.

The team’s paper, “A climatic context for the out-of-Africa migration,” is published online in Geology this week. Tierney’s co-authors are Peter deMenocal of the Lamont-Doherty Earth Observatory in Palisades, New York, and Paul Zander of the UA.

The Lamont-Doherty Core Repository contains one of the world’s most unique and important collection of scientific samples from the deep sea. Sediment cores from every major ocean and sea are archived here. The repository provides for long-term curation and archiving of samples and cores to ensure their preservation and usefulness to current and future generations of scientists. Image courtesy Lamont-Doherty Earth Observatory

The National Science Foundation and the David and Lucile Packard Foundation funded the research.

Tierney and her colleagues had successfully revealed the Horn of Africa’s climate back to 40,000 years ago by studying cores of marine sediment. The team hoped to use the same means to reconstruct the region’s climate back to the time 55,000 to 70,000 years ago when our ancestors left Africa.

The first challenge was finding a core from that region with sediments that old. The researchers enlisted the help of the curators of the Lamont-Doherty Core Repository, which has sediment cores from every major ocean and sea. The curators found a core collected off the Horn of Africa in 1965 from the R/V Robert D. Conrad that might be suitable.

Co-author deMenocal studied and dated the layers of the 1965 core and found it had sediments going back as far as 200,000 years.

At the UA, Tierney and Paul Zander teased out temperature and rainfall records from the organic matter preserved in the sediment layers. The scientists took samples from the core about every four inches (10 cm), a distance that represented about every 1,600 years.

To construct a long-term temperature record for the Horn of Africa, the researchers analyzed the sediment layers for chemicals called alkenones made by a particular kind of marine algae. The algae change the composition of the alkenones depending on the water temperature. The ratio of the different alkenones indicates the sea surface temperature when the algae were alive and also reflects regional temperatures, Tierney said.

To figure out the region’s ancient rainfall patterns from the sediment core, the researchers analyzed the ancient leaf wax that had blown into the ocean from terrestrial plants. Because plants alter the chemical composition of the wax on their leaves depending on how dry or wet the climate is, the leaf wax from the sediment core’s layers provides a record of past fluctuations in rainfall.

The analyses showed that the time people migrated out of Africa coincided with a big shift to a much drier and colder climate, Tierney said.

The team’s findings are corroborated by research from other investigators who reconstructed past regional climate by using data gathered from a cave formation in Israel and a sediment core from the eastern Mediterranean. Those findings suggest that it was dry everywhere in northeast Africa, she said.

“Our main point is kind of simple,” Tierney said. “We think it was dry when people left Africa and went on to other parts of the world, and that the transition from a Green Sahara to dry was a motivating force for people to leave.”

###

This 80’s song seems both prescient and appropriate, especially the part about the rains.

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132 thoughts on “The world’s first and only “climate refugees” – Ancient Africans

  1. No computer models used in the study? Must be bogus!

    Actually good for Tierney et al. It had to take some effort to find suitable cores and then figure out a way to quantify the results. Quite frankly we do have some very capable people out there that can do real science and although I didn’t buy the paper and read it, I’m guessing the methods and results are probably well defined allowing subsequent followup or replication to be done.

    It is such a shame there has been so much garbage science done over the past couple of decades that tarnishes good science.

  2. The problem with this is that it only deals with anatomically modern humans, as H heidelbergensis and other archaic humans were in Eurasia much earlier. One can get into an interminable discussion (as it is nearly content free) on the actual advantages modern humans had over archaics.

    • Yes, many conveniently ignore the fact that humans and their culture/abilities also change over time, or even have the occasional bout of war and disease.

      And why focus just on the climate at the origin of migration, and not mention the climate at the destination? Humans likely migrated all the time and success at the destination is just as important as ‘failure’ making life harder at the origin.

      • True enough. it still occurs today. Every winter climate refugees seek shelter from the northern freeze in the warmer havens of the south…because it is much nicer there. One rarely migrates to a pasture where the grass is just as green or even less so.

    • The young in pretty much all species are always walking about looking for territory that isn’t already claimed by a larger more mature male.
      There’s no reason to assume that man would have stayed in Africa had the climate remained stable.

      • Exactly, competition for available resources (including territory) seems like a more valid explanation for migration.
        Therefore, a burgeoning population would be the primary cause, with climate change a bit player affecting resources available.

    • Tom Halla
      Agreed.
      We know a little about a complex process.
      I – on a personal view – think there is a possibility that H. sapiens – anatomically modern humans, like you and me and Donald Trump – evolved by mixing and splitting etc. outside Africa [probably in the Middle East/Asia minor].
      A possibility only at the present state of knowledge [or presumed knowledge].

      Auto – wondering . . . .

  3. “We think it was dry when people left Africa and went on to other parts of the world, and that the transition from a Green Sahara to dry was a motivating force for people to leave.
    I agree the Roman warming period was also a futher example = No grains – No bread!

      • “Yeah but i never understood why he wanted to kiss the rain.”
        I have never been to Africa so may not be in the best position to answer. I did grow up in a family agriculture business. I have seen times when I would have gladly kissed nearly anything for just half an inch of rain at the right time.
        It is very difficult to work hard for months and have your livelihood for the year dependent upon the rainfall over the span of a few weeks.
        I also have never been the best at interpreting prose and poetry for embedded imagery, metaphors, etc. So, I could be as far wrong as possible. But, that would be my interpretation.
        For whatever my opinion might be worth. Use at your own risk.

      • Too little and the crops won’t grow, too much and you can’t work the fields. I always reckoned the best way to keep everyone happy was to have half an inch of rain every Sunday night.

  4. 60,000 years corresponds pretty well with the heart of the last glaciation doesn’t it? Cold times are dry times.

    • Even during the last glacial age, temperatures were going up and down. I am watching a graphic on the temperature in Greenland ice cores, and the periods with more cold were 60,000 years ago, with 2.500 years of cold, other were 46,000 y.a. with one thousand years of cold; other was 39,000 y.a. with some 1.3 thousands years duration. 29,800 y.o. with some 1.2 thousand years duration.
      This is the first graphic I found. It goes from 27,000 to 65,000 y.a. Other periods of cold were or shorter duration lasting for 5 to 7 centuries only. I count some 14 short periods of cold for this graphic
      I would love to send you some graphics on my replies. But I can print any graphic here.

    • Cold times are dry times. As Jeff in Calgary says. The problem is so much of the earths water tied up in ice and vast areas of oceans and other bodies of water covered in ice. And of course weather patterns changed. What were once forests became savannas. What were once savannas became grasslands. What were once grasslands became deserts. Cold deserts can be just as dry as hot ones. The fauna living in the areas that change can do any of three things; Migrate to more suitable conditions, adapt to the changing conditions, or die.

      Africa

      • Since 70% of Earth’s surface is water (if that is the correct measurement – surface?), even if much is tied up in ice, one might think that those concerned with climate change would be imagining and planning for preventing drought that matters (agriculture, ranching especially) forever more.

        Flooding also should mostly be prevented. Too wet at the wrong time, a bit more troublesome, but if the first two, drought and flooding, were taken care of, this one might yield to human intelligence and technology as well.

        It is so unfortunate that trillions of dollars have gone into “global-warmer elitist” pockets due to fraud — scientific and governmental — that these human issues we all know to be the most crucial have not been attended to.

        Civilizations fall and chaos descends whenever there is true major climate change.

  5. The world’s only climate refugees? What about the cultures that left Greenland after the onset of the LIA? Or were they completely wiped out by climate change?

    • The Greenland case is reserved for distortion on unsustainable farming under the NOVA program credo of “explore new ideas” and all other ideas are not welcome or not aired.

    • There are multiple examples of North to South migrations in Eurasia. Anyone familiar with the history of India would know that India was invaded by Northern Tribes (Aryans, Mongols, Persians) whenever the world entered cold periods . One could argue that many Scandinavians migrated to the U.S. towards the end of the last ice age because they couldn’t grow enough food.

    • And the volkswanderung during the middle of the first millennium A.D. during the cold between the Roman and the Medieval warm periods? I think both the cold and the migrations are fairly well documented. Correlation is not causation, of course

    • Then there was the migration from the dust bowl areas to California during the 30’s. I’d call them climate change refugees as well.

      • “I’d call them climate change refugees as well.” Really? The “Dust Bowl” was caused by a weather pattern change and poor farming practices and lasted a short period of time. So I would call them weather change refugees.

      • I would note that some scientists were calling for the evacuation of people from the Dust Bowl areas at the heighth of the 1930’s heatwaves.

        Imagine if that had been done.

        A lot of Dust Bowl victims migrated to California, but most of them stayed in the Dust Bowl and toughed it out. And we are still here today, enjoying some of the best weather evah! No Dust Bowls or heatwaves, and the grass stayed green throughout the summer.

        Compared to the 1930’s, today is a cake walk.

    • Why is anyone surprised that if a culture can no longer grow enough food to survive, it migrates (if it can) or dies out? And if it died out long enough ago we would have no way of knowing about it.

    • From http://www.science20.com/news_articles/6000_years_of_climate_change_through_egyptian_history-144401 (my bold):

      The researchers identified five episodes over the past 6,000 years when dramatic changes occurred in Egypt’s mammalian community, three of which coincided with extreme environmental changes as the climate shifted to more arid conditions. These drying periods also coincided with upheaval in human societies, such as the collapse of the Old Kingdom around 4,000 years ago and the fall of the New Kingdom about 3,000 years ago.

      There were three large pulses of aridification as Egypt went from a wetter to a drier climate, starting with the end of the African Humid Period 5,500 years ago when the monsoons shifted to the south,” Yeakel said.

      As climate always changes, often in dramatic ways that cannot be countered, there must have been many instances of large numbers of peoples moving from one area to another.

      • “Climate change” cannot be countered, but its effects can. We can develop adequate water distribution as well as protection against major flooding. Also protective earthquake building engineering. Probably mass wasting such as massive landslides are a bit more difficult, but they tend not to be civilization-destructive. Volcanoes and meteorites, a bit more problematic.

        We do not have to think passive thoughts, although those who are scarfing up the trillions from the climate scare fraud wish us to do so. There are mountains of data from every region compiled by real scientists over the last 100 years that gives the “worsts” of the area’s climate history from which denizens can plan to survive.

        We don’t have to wait for migrations and invasions from the Four Horsemen.

    • “Or were they completely wiped out by climate change?”

      As far as we know the Norse colonists were completely wiped out by the LIA. And a little later the inuits in Northeastern Greenland were wiped out as well.

      By the way when the Norse settled southern Greenland during the MWP it was uninhabited, though they found signs of former inhabitants. The Cape Dorset eskimo didn’t have kayaks and were dependent on hunting seals on the winter ice, so during the MWP southern Greenland with ice-free winters was too warm for them. The Norse only found them up north from Disko Bay northwards.

  6. Those who abandoned northern Europe during the Last Glacial Maximum were also climate refugees. They developed the Solutrean Culture in refugia in southern France and the Iberian Peninsula.

    • and then later on, climate change allowed migration back north.

      Forced migrations (north Europe glaciation); “encouraged” migration (out of Africa heading to greener pastures), “allowed” migration (low sea level & and end of glaciation … moving on to see what’s out there).

      Seems that today’s movements are politically encouraged migrations.

      • Today’s migrations are motivated by the green of money, whether from Africa and Asia to Europe or from Latin America, Africa and Asia to North America.

  7. No no no! Global warming refugees are a new thing. And according to this UCSB / USGS study, we have to plan for it. Because Africa never had droughts, or food security issues before. (Sarc)
    ————————————-
    Planning for the future
    UCSB and USGS collaborators model how changes in climate and socioeconomic status will likely affect health outcomes in sub-Saharan Africa
    Over the past decade, increasing temperatures across much of Africa and decreasing rainfall across East Africa have come to represent an alarming climate trend. Chief among concerns is the impact such conditions have on human health.
    https://www.eurekalert.org/pub_releases/2017-10/uoc–pft100517.php

  8. Wait! It got drier AND colder? I thought drought happened when earth heated up? That’s what Algore keeps saying, “global warming will result in greater drought”.

    It *must* have been caused by increased CO2 from human campfires.

    • The followers of Goreism believe that man is in ultimate control of nature. Whether it gets colder, warmer, windier, wetter, drier, there are more impacts or more earthquakes, it’s all the consequences of something mankind did, or didn’t do. Similar to the mindset that drove people to accept an Earth centric Universe.

      • The followers of Goreism have transferred the concept of original sin from noshing forbidden fruits to the domestication of fire — sort of a mishmoshed update of the Fall From Grace mixed into the Myth of Prometheus. They’re appointed themselves as final arbiters, like the Olympian gods. Mankind must refrain from sin, i.e. give up the use of fire, or suffer eternal torment. Either have your liver eaten out daily by eagles, or suffer constant hectoring by fanatics and hypocrites like Bill McKibben and Leonardo DiCaprio. Like the Olympian gods, Gore, DiCaprio & Co. can continue to use fire in the form of their jet travel, electronic newsletters, studio lights, media dominance and so on. It’s only the hoi polloi who are required to return to primitive conditions. One set of rules for the Gorists, another set of rules for us little people.

    • Algore believes global warming will result in greater meddling by blockheads. That’s not how he phrases it, but that’s what he wants.

  9. “unsuccessuly?” lol Tony

    The period leading up to the early OOA migrations fascinates me, because practically all of modern baseline human psychology probably became fully developed around then, and so that period still has implications for how we live today.

    ““It’s interesting to think about how our ancestors interacted with climate,” she said.”

    It likely involved a lot of handaxes to the backs of skulls.

    • unsuccessuly unsuccessuly unsuccessuly unsuccessuly unsuccessuly unsuccessuly unsuccessuly

      It’s all I can see, please make it stop!

  10. well and fine….except the migration out of Africa is in question now

    “the Horn of Africa shifted from a wet phase called “Green Sahara” to even drier than the region is now. The region also became colder.”

    …so they moved to the ski resorts of Europe..where it was even colder and drier

    • From what I have read, the human population of Africa is far more diverse genetically than the humans of Europe. This suggests that the European population represents a “founder” effect. Much like HIV. There are many more species of HIV in Africa than in Europe or North America.

    • Jim,

      That’s about the origin of our lineage over seven million years ago, not of anatomically modern humans some 200,000 years ago.

      Joel,

      Genetic diversity is greater in Africa than in the rest of the world, because more haplogroups stayed there than left. Genetic diversity in parts of Africa between adjoining regions or even neighboring villages can be greater than in all of Asia, Europe, Australia and the Americas combined.

      For instance, forest pygmies live not all that far from the giant (if slender) Nilotic peoples, and gracile “Bushmen” not far from burly Bantus.

  11. It’s interesting that man headed from the equator towards the N pole 70K years ago as the Earth was heading into the deepest part of the last ice age, which apparently took a while to be noticed close to the equator.

  12. I have no idea if Tierney et al are correct or wrong
    This graph (Department of Oceanography, Texas A&M University) shows what temperatures and sea level change trends were around time in question.

    Top panel shows the oxygen isotope record (δ18Oice) from the Greenland Ice Sheet Project II (GISP II) ice core over the last 80,000 years (Stuiver & Grootes 2000). Colder air temperatures are indicated by more negative δ18Oice values. Bottom panel shows changes in global sea level over the same time period (Waelbroeck et al. 2002),
    Perhaps falling sea level in Mediterranean made flora and fauna flourish in the vacated land costal strip providing migrants with plenty of food and so enabling easy movement from Africa towards Europe and Asia (just a thought).

    • That interval was already one of the coldest of the last glacial before its maximum around 20 Ka. But there is also this:

      “The Toba supereruption was a supervolcanic eruption that occurred some time between 69,000 and 77,000 years ago at the site of present-day Lake Toba (Sumatra, Indonesia). It is one of the Earth’s largest known eruptions. The Toba catastrophe hypothesis holds that this event caused a global volcanic winter of 6–10 years and possibly a 1,000-year-long cooling episode.”

      • Apparently the Toba supervolcano eruption reduced the global human population to about 1000 breeding pairs. The population of a single village. Scary. 3000 km^3 of ash were ejected (compared to 3 only from Mt St Helens). It’s possible that the reason that the mitochondrial haplotype L3 labelled modern migrants out of Africa 60,000 years ago populated the world with their descendants, is that theirs was the first breakout after Toba, into a world emptied of people.

      • Ptolemy,

        I ascribe to this hypothesis, which does indeed have good genetic support. However, it was a bottleneck only for those outside of Africa. That continent was surely affected, but less so than anyone who might have lived outside of it. And the effects of the megaeruption might well have encouraged Africans to look farther afield for game to hunt.

    • This map (from wikipedia ) shows possible routes of modern human migration based on DNA’s y-chromosome grouping analysis

      (click to go to the original, click again to enlarge)
      Grey areas show extent of land due to sea level fall at the time of the last glacial.

  13. Not completely true. Just checked to make sure my memory wasn’t faulty. The Daoxian discovery in Hunan China in 2015 shows that Homo sapiens reached eastern China about 100,000 years ago (ya). See Nature 10/14/2015. That migration wasn’t related to this change in north African climate ~60,000ya.
    There was a second migration wave into Europe and central Asia 40-60kya which could have been climate motivated, or enabled by the decline of Neandertals, or both. But most of the earliest Homo sapiens dating in eastern and southern Europe is ~40kya, again not closely contemporaneous with this newly reported shift from ‘Green Sahara’.
    Not so clearcut, this climate refugee hypothesis.

    • Europe was colonized by moderns already long resident in the Middle East. Older artifacts of their Aurignacian culture have been found as far east as Iran.

      The Dravidian people of southern India and Aborigines of Australia (also presumably New Guineans) are thought to represent the out of Africa migration cited in this study.

    • Ristvan
      The Daoxian discovery of 80,000 year old remains and other isolated finds in Papua New Guinea etc. are the exceptions that prove the rule. Genetic analysis makes it clear that the breakout group from which the vast majority of today’s humans outside Africa are descended, was the mitochondrial haplotype L3 labelled migrant group of a few hundred who crossed the Red Sea from Africa to Asia about 60,000 years ago.

  14. The out of Africa migration around 50-60,000 years ago was not the first human radiation out of Africa. (There is at least consensus that Africa was the origin of the very first hominids and humans.) Earlier humans that were most likely members of the much older species Homo erectus and Homo heidelbergiensis, also migrated out of Africa as long as 2 million years ago and spread widely throughout Eurasia and Europe. There were probably indeed several such break-outs. They left descendants in Europe called the Neanderthals, and in Eurasia called the Denisovans. One remarkable group of archaic humans made it as far as the Indonesian island of Flores, where a million years of isolation led them to become so much smaller than other humans – only half the height – that scientists discovering their diminutive skeletons have called them “hobbits”. This unique hominid Homo floresiensis, survived until only fifteen thousand years ago – the most recent survival of any other species of human.
     
    However the migration of modern Homo sapiens which took place 50-70,000 years ago had special significance. It was the first departure of Homo sapiens from Africa after they had become recognisably modern and acquired skills of advanced tool use and language, and had begun creating art works. It should be noted that at this time there were only African modern humans on earth: today’s racial diversity of modern humans would come much, much later. For instance the pale skin of northern Europeans still lay in a distant future, less than 10,000 years ago in the Holocene interglacial, when the thick northern ice sheets finally melted.
     
    Genetic analysis shows that one particular migration event was carried out, about 60,000 years ago, by a small group of people genetically marked with “Mitochondrial Haplotype L3”, and that, astonishing, all humans today all over the world, with the exception of some in Africa, are descended from this single exodus. This founding group of migrant ancestors probably consisted of just a few hundred individuals, the number of people at an average wedding party 🎈 . These modern L3 labelled migrants from Africa spread all over the world and survive to this day – as most of us – while the Neanderthals, Denisovans, hobbits and other ancient descendants of the much earlier Homo erectus / heidelbergiensis radiations from Africa, did not.

  15. We had dustbowl refugees in the dirty thirties.

    I’m a dust bowl refugee,
    Just a dust bowl refugee,
    From that dust bowl to the peach bowl,
    Now that peach fuzz is a-killin’ me.

    We had the Irish fleeing the potato famine. They weren’t exactly climate refugees but close …

    How about when the Vikings left Greenland at the beginning of the Little Ice Age?

    I think we have had climate refugees rather often.

    • My tribe of south Slavs left shores of the Baltic Sea in the north Europe sometime in the 6th century AD because crops were failing due to cooling climate. They fought Germanic and other tribes along the way to finally, about nearly century later, invade the Balkan parts of the East Roman Empire pillaging civilized Byzantine towns and cities. Thankfully, eventually they converted to Christianity and learned literacy, building of magnificent churches and art of frescoes from their Byzantine foes, and in doing so made important contribution to the European civilization of 13th and 14th century (regretfully not much advancement since due to the following five centuries of resisting and repelling the islamic Ottoman invaders from Asia).

    • Actually the potato famine was climate-induced. The potato blight requires summers that are wet (common in Ireland) and warm (which is not).

      • And before that the potato became a staple because of climate change during the LIA. Tubers can thrive in colder conditions where most grain crops fail.

  16. Horn of Africa:

    https://www.google.com/maps/vt/data=9BDCiqHsbO0zGU_WFF9xcp8ObVW8DWdySpzRZX8MB_scKVoOC2Qfv8gdI_ZFPwjqgpWcmThNxIxQBAozWK3uV01CB60NFzgeGRVqtZT-2ClE6eHsgg6ScnsQLEIFCTjUPNxDG9guKC6L3WNuAtF4Nidbd1NsGHQt4HiaKgin7IvW6T_qcLOYH5xIhRqpVdyMpWKwTG6ylFHehg0XECuPCA

    Note that his study is based on a single core of marine sediment.

    The study doesn’t seem to take into account (if such info exists) prevailing east/west
    winds during the deposition periods of the core. Nowadays the prevailing winds for
    the Horn of Africa run east to west across the continent and over to the Atlantic.

    New cores from the inland areas of the Sahara and sub-Sahara are not available,
    mostly due to the extreme physical danger researchers might run into unless they
    have military escorts.

    I’m not sure the waxy buildup they’ve used as a marker is all that revealing.

    • … but where do I go to get away from all their crap. It’s causing me much head shaking, which can cause vertebral harm, and this could lead to my injury lawsuit.

      I’m feeling a precedent coming on. Supreme Court, get ready.

  17. This takes me back forty years when I used to sample cores are LDGO. Such repositories are invaluable storehouses of information waiting to be processed, analyzed, and understood.

  18. Why did Humans cross through the Levant to Eurasia?

    To see what was on the other side.

    Dry climate – smimate.

    C’mon. We crossed it when we got there. Just like Home Erectus did and Australopithecus did (the latest evidence on Homo floresiensis).

    We didn’t get to everywhere on this planet because we didn’t like to explore. It is precisely for that reason that we did.

    • Bill,

      I’m dubious about the Hobbit as an australopith. I know the alleged evidence cited, but a dwarf subspecies of H. erectus is still much better supported.

      IMHO.

  19. Another plausible group of climate refugees are the Cimbri, who abandoned their homes in Jutland most likely after a catastrophic storm tide:

    The Cimbri were an ancient people, either Germanic or Celtic who … fought the Roman Republic between 113 and 101 BC. … The contemporary Greek geographer Strabo testifies that … “some things that are told about them are extremely improbable. For instance, one could not accept … [that they were] … driven out of their habitations by a great flood-tide …”

    Strabo probably couldn’t know that the North Sea causes frequent catastrophic floods that drowned people by the thousands.

  20. During the time when so much water was locked up in the Arctic glaciers and the Sea level was hundred(s) of feet lower, there would also have been land bridges at what is now the Strait of Gibraltar, the Bosporus, and the Bering Strait. There would have been no water in what is now the Red Sea or the Black Sea. I think that we make the mistake of looking at the map the way it is now instead of how it would have been then.

    Less water would have made the living harder in places, but less water would have made the migrations easier.

    • Bering strait, for sure. Max depth 160 feet. Allowed Siberians to become Amerinds by walking. Bosporus, for sure in places, max depth 120-420 feet. Facilitated migration from central Asia to Europe by walking. Also for sure Sunda in Indonesia, and English channel north end at Dogger Bank.
      Strait of Gibralter, no way. Max depth 900 meters or ~3000 feet.

    • I’ve read that the Black Sea was a freshwater lake during this time, some 300 to 400 feet lower in elevation than present.

    • The Red Sea has never been dry during the Pleistocene, sea level was apparently never quite low enough, though the Bab el Mandeb must have been quite narrow during maximum glaciations.

      • Yup. Its central channel is about 250 m deep, but falls off steeply on both sides from ~40 to 60 meters deep on the continental shelves. The channel is around six miles wide at its narrowest. Maybe less. At the LGM, it would have been only some 110 m deep. In places there would have been 80 cliffs, but no doubt paths down to the water existed.

  21. This was certainly NOT the “only” climate change causing shifts in human populations. Each glacial period undoubtedly forced many human groups to leave glaciated areas. It’s hard to make a living on glaciers. Also, parts of the Saharan Desert were much wetter during the Holocene Optimum and supported savanna fauna and human populations that had to migrate out of the region when it later turned into the present desert. I suspect there are many other examples. Humans in the past were very good at adapting when populations were relatively small. However, the next glacial period will likely create massive havoc unless humans find a way to prevent it.

  22. This research from Arizona University is important new knowledge fitting in well with what is already known about the modern human out-of-Africa migrations.

    This figure posted above by Vukcevic shows that the majority of the last glacial interval was characterised by dramatic, often violent excursions of climate change, such as the Dansgaard-Oescher “micro-interglacials”.

    Evolution researchers consider that the frequent wide climate oscillations over the whole of the Quaternary glacial age, with biomes in Africa alternating between forest 🌳 grassland and desert 🌵 has played a crucial role in human acquisition of intelligence and tool use, since these were needed to adapt and survive. If you weren’t a crocodile.

  23. The number one cause of Catastrophic Anthropogenic Climate Change are social justice adventures (i.e. elective wars, regime changes). Well, two. The need to obfuscate the environmental disruption by proponents of “clean” wars, and an unprecedented loss of life in a-abortion chambers operated by national and international socialists, is a first-order forcing of CAIR (Catastrophic Anthropogenic Immigration Reform).

  24. The number one cause of Catastrophic Anthropogenic Climate Change are social justice adventures (i.e. elective wars, regime changes). Well, two. The need to obfuscate the environmental disruption by proponents of “clean” wars, and an unprecedented loss of life in a-bortion chambers operated by national and international socialists, is a first-order forcing of CAIR (Catastrophic Anthropogenic Immigration Reform).

  25. Um, what has happened when the lands currently called Camada, the UK, Russia, Sandinavia etc. were covered by ice? I suggest people probably had to move south, as will we, in just a few thousand years with only a few hundred years warning, Crisis, disaster, catastophe, AKA natural long term climate variability..

    • brianrlcatt

      Um, what has happened when the lands currently called [Canada], the UK, Russia, [Scandinavia] etc. were covered by ice? I suggest people probably had to move south, as will we, in just a few thousand years with only a few hundred years warning, Crisis, disaster, catastophe, AKA natural long term climate variability..

      No, I’m going to disagree with you here about this most recent Western Hemisphere Ice Age refugees.
      Granted, they “probably” left Siberia trying to find new lands for grazing and hunting – though they left Siberia in the midst of the Ice by traveling “north” towards Alaska and the Bering Strait seafloor uncovered BECAUSE the western hemisphere glaciers and ice mass reduced sea levels enough to cross over “safely” .

      But the first humans arrived in North America (and promptly killed off all large mammals living here!) during the depths of the Ice Age around 12,000 – 13,000 years ago. If they were driven from Asia because of the Ice Age, they were “refugees”. If they left Asia and North Europe like the Huns, Visigoths, Goths, Franks, and hundreds of other tribes (followed later by the Mongols) did between 150 and 500 AD, they were conquorers and invaders. Forced out by climate perhaps, but certainly not “refugees”!

      • RACookPE1978 October 5, 2017 at 4:09 pm
        brianrlcatt

        No, I’m going to disagree with you here about this most recent Western Hemisphere Ice Age refugees.
        Granted, they “probably” left Siberia trying to find new lands for grazing and hunting – though they left Siberia in the midst of the Ice by traveling “north” towards Alaska and the Bering Strait seafloor uncovered BECAUSE the western hemisphere glaciers and ice mass reduced sea levels enough to cross over “safely” .

        Recent work has shown that the first arrivals were probably by boat before the ice-free corridor became passable.
        See Science, 11 Aug 2017, pp542.

      • Don’t agree that people lived on the ice cap from choice. What do they live on and how do they shelter and stay warm on an ice cap? Which reached 50 degrees latitude?

        Unlikely, if there was land , animals and fish further south. Migration was how hunter gatherers lived, they wre not settled. Where does their personal and heating energy come from? No enrgy, no life. What lives on land covered in ice sheets? People would move unless trapped when the ice came, or face life on very thick and inpenetrable land ice where there is nothing to grow or growing, or to hunt or fish. What I suggested is what the record appears to show. The means of transport around the Pacific rim is now suggested to be probaly water, coastal navigation, too hard on land, and that probably happened in the previous interglacial, land bridges not necessary, although the Bering straight is only 50 metres max deep, so crossable in an ice age, but maybe that wasn’t the route? Alaska is no fun to traverse.

        Note the Polynesians could cross the open Pacific, if you have watched Moana you now that.The early migrations from Africa made it to South America this way, setting up coastal settlements on the way, nothing much to the East of the Andes/Rockies/Sierras. In S Smerica they finally met their brother met Cortez et al coming the otherway, same genes but one called the other primitive and massacred them for supposed gold. I don’t think it likely anyone tried to live in top of land based ice caps. Life was unsupportable then and even today requires constant supplying from ice free areas today. Illogical, Captain :-)
        They were driven South by the ice, so were refugees from it. People moving to refuge elsewhere from a problem where they were that was life threatening BTW.

  26. I’ve been a climate refugee for most of my adult life, taking refuge in warm places during the northern winter. Then I flee the heat of those places.

  27. When the climate changes, people really notice of their own accord and take appropriate action.. They do not need relentless propaganda from the media to notice real climate changes.

  28. Did I read that right? They found only one core to study? If so, then this paper should not have been written until more data was available. While not quite in the category of Briffa’s one single tree, this study is similarly methodologically unsound. It is so typical of today’s science where it is all about getting as many papers out of as little data as possible. Publish or perish.
    I might actually agree with the findings but that is merely a reflection of confirmation bias, not an indication of scientific validity.

  29. Apparently
    “Modern European and Asian people may owe more than skin or hair colour to Neanderthal ancestry. Matching modern genetic profiles against genes known to have been inherited from Neanderthals has shown links to a wide range of current disorders. ………… Our main finding is that Neanderthal DNA does influence clinical traits in modern humans. …. The brain is incredibly complex, so it is reasonable to expect that introducing changes from a different evolutionary path might have negative consequences”
    claims Guardian
    Now we know, all Euro-Asians depressed by prospects of ‘catastrophic global warming cataclysm’ are much closer to Neanderthals than previously thought, which is no surprise, the Neanderthals prospered during the last glacial.

    • Actually “bad” Neanderthal genes got selected out. There are so called “Neanderthal deserts”, i e parts of the modern eurasian genomes that contain no neanderthal genes at all. This is true e g for genes connected with language capabilities, suggesting that neanderthals were significantly inferior in this area. Neanderthal genes seem to be most common for genes that are connected with the immune system, which seems reasonable, the neanderthals probably had acquired resistance for a lot of nasty things that africans had never encountered before.

  30. The other day I read that scientists have found ancient humanoid bones in Europe that bring the whole theory of the migration out of Africa into question. It seems the European bones are older than the African ones. I guess that blows the ‘left Africa due to climate change’
    hypothesis out of the water. Oh well. Back to the drawing board.

    • A problem is both where people doing paleontology look for fossils, and sites with good fossils. There are a lot more people looking in places like Europe (or South Africa), so they should find more fossils. Then there is the issue of where such fossils could form, which might or might not correspond to where the hominids actually lived.

    • Those bones are actually late Miocene, about six or seven million years old. They might indicate that the common ancestor of humans and chimps immigrated to Africa from Eurasia.

      This is not a new idea by the way. There is an interval during the Miocene when no hominine fossils are known from Africa, but they do occur in Eurasia, so it has been hypothesized that hominines became extinct for a while in Africa, which was then repopulated from Eurasia. But this was way back and does not affect the “out of Africa” paradigm in the slightest. That is just ignorant sensation-mongering journalism.

      Never believe anything you read about scientific matters in the MSM, it is almost certainly either flat-out wrong or misunderstood.

    • Cally
      You may be referring to research that found possible 6-7 million year old proto-humans in the Greece/Bulgaria/Turkey region. However back at that time there was no Mediterranean so this area would be continuous with North Africa. So the finding changed little regarding very early human origins.

  31. If not for the out-of-Africa migration, there would be only one race – African. The races evolved as adaptations of humans to their local environment and climate. We have climate change to thank for the different races. We don’t want to be all Africans. That’s not a racist remark lol

    • Actually there is at least two quite distinct races in Africa south of the Sahara, the Khoisan and the “N-worders”.

      • IMO there are no human races at all, in the biological sense of subspecies. Humans show remarkably little genetic variation, despite a global distribution, compared for instance to chimps. Maybe a bottleneck from the Toba eruption accounts for this fact.

        There are however genetically distinct groups, such as the Khoisan (“Bushmen”) v Bantus and other African populations, and those outside Africa.

      • Bantu is a language group, not a population. And you make a very common mistake, confusing raw genetic distance (which is almost exclusively a function of the length of time two populations have been separated) with significant genetic changes, which are subject to selection.

        Most mutations have no somatic effect at all or are neutral from an evolutionary viewpoint. However it does not necessarily take very many mutations, or a very long time, for a subspecies or even a species to evolve. Especially if sexual selection is involved.

        The raw genetic distances within Homo sapiens are small, yes, but the morphological differences between different subspecies are actually remarkably large, compared to most other mammals.Some subspecies are even osteologically determinable, i. e. can be identified on skeletal characters, which is quite unusual. Human subspecies differ significantly in a remarkably large number of ways: size, pelage color and structure, skin pigmentation, body proportions, iris color, tooth morphology, distribution of subcutaneous fat, cranial morphology, immune system characteristics etc etc.

        And then there is a qualitative difference we didn’t even know about until recently. Africans are (almost) pure Homo sapiens, everybody else are hybrids of even triple hybrids.

        And as mentioned above the sapiens/neanderthal/denisova hybridization shows that 500,000 years of isolation is enough to cause partial sterility in human hybrids, so 50,000 years is actually something like 10% of the way to a separate biological species.

      • Many of the races are related. Here’s my own classification based on physical appearance and ancestry. By coincidence, 7 is the ancient mythical number

        1. African, Australian aborigine
        2. Caucasian-European
        3. Intuit, Mongolian, Native American, Aztec, Mayan
        4. Syrian, Egyptian, Babylonian, Hebrew, Persian, Arab, Turk
        5. Indian, Pakistani, Sri Lankan, Burmese, Bangladeshi
        6. Chinese, Japanese, Korean
        7. Polynesian, Malay, Indonesian, Cambodian, Vietnamese, Thai

        All others are mixed races. Latinos are a mix of Caucasian and Aztec-Mayan. Mongolia is far from South America but in the last ice age, there was a land bridge in the Bering Strait. They probably originated in Siberia and migrated to North and South America. This ancient people were also the ancestors of Mongolians.

      • Many of the races are related. I counted 7 races based on physical appearance and ancestry.

        1. African, Australian aborigine
        2. Caucasian-European
        3. Inuit, Mongolian, Native American, Aztec, Mayan
        4. Syrian, Egyptian, Babylonian, Hebrew, Persian, Arab, Turk
        5. Indian, Pakistani, Sri Lankan, Burmese, Bangladeshi
        6. Chinese, Japanese, Korean
        7. Polynesian, Malay, Cambodian, Vietnamese, Thai

        All others are mixed races. Latinos are a mix of Caucasian and Aztec-Mayan.

      • Not by inferred ancestry, Africans are maximally distant from Australian Aborigines. By DNA variations, Africans have more diversity than all other groups, going off reports by Cavalli-Sforza. Dark skin developed several times, apparently.

  32. Just like CAGW timelines and the length of time it takes for things to actually happen are far, far longer than the media and the CAGW crowd would have use to believe. Even if they are right and we will not know until most of us are gone, the CAGW crowd compresses timelines down to years, decades and elections cycles and have to a certain extent overplayed their hand. If it one does not let any “good crisis go to waste” the average person doesn’t see or care about crises beyond their lifetime, maybe their children’s. Having minored in anthropology and long discuss human and protohuman migrations there is little doubt that changes in climate played a role both in SLOWLY driving humans from one place to the next but in also providing new opportunities. A large percentage of humans are risk takers and explorers, they seek the unknown, what is over the next hill. That tendency probably evolved during our hunter-gather era. Of course a trait from that era that has gets us in trouble today is denial. Going up against large megafauna it was a required trait or we wouldn’t have eaten. Today it gets the average person in trouble daily.

  33. Two words — denialist camps

    These are places where catastrophic-climate skeptics can go to live climate-alarmist-free. They will be upscale, gated communities with tight security and strict ideological preferences, to insure that science is given a fair shake. No posters of Michael Mann allowed, … no visiting skepticalscience.com allowed – visited IP addresses are monitored electronically, and so anytime such a visit is detected, a community alarm goes off, alerting all community members to grab stones and clubs to correct the situation.

    Yes, it’s extreme, but extreme stupidity calls for extreme measures.

  34. Here in Scotland around 6,000 years ago, it is generally accepted that the climate cooled and got wetter, leading to the movement of people from higher altitudes to lower altitudes,

    • Yes, and there was a similar movement at the end of the MWP. In the Lammermuir hills the upper limit of cultivation sank 200 meters between 1300 and 1600.

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