Results show that the correlation between climate change … and the loss of megafauna is weak
A new study unequivocally points to humans as the cause of the mass extinction of large animals all over the world during the course of the last 100,000 years.
Was it mankind or climate change that caused the extinction of a considerable number of large mammals about the time of the last Ice Age? Researchers at Aarhus University have carried out the first global analysis of the extinction of the large animals, and the conclusion is clear – humans are to blame.
“Our results strongly underline the fact that human expansion throughout the world has meant an enormous loss of large animals,” says Postdoctoral Fellow Søren Faurby, Aarhus University.
Was it due to climate change?
For almost 50 years, scientists have been discussing what led to the mass extinction of large animals (also known as megafauna) during and immediately after the last Ice Age.
One of two leading theories states that the large animals became extinct as a result of climate change. There were significant climate changes, especially towards the end of the last Ice Age – just as there had been during previous Ice Ages – and this meant that many species no longer had the potential to find suitable habitats and they died out as a result. However, because the last Ice Age was just one in a long series of Ice Ages, it is puzzling that a corresponding extinction of large animals did not take place during the earlier ones.
Theory of overkill
The other theory concerning the extinction of the animals is ‘overkill’. Modern man spread from Africa to all parts of the world during the course of a little more than the last 100,000 years. In simple terms, the overkill hypothesis states that modern man exterminated many of the large animal species on arrival in the new continents. This was either because their populations could not withstand human hunting, or for indirect reasons such as the loss of their prey, which were also hunted by humans.
First global mapping
In their study, the researchers produced the first global analysis and relatively fine-grained mapping of all the large mammals (with a body weight of at least 10 kg) that existed during the period 132,000–1,000 years ago – the period during which the extinction in question took place. They were thus able to study the geographical variation in the percentage of large species that became extinct on a much finer scale than previously achieved.
The researchers found that a total of 177 species of large mammals disappeared during this period – a massive loss. Africa ‘only’ lost 18 species and Europe 19, while Asia lost 38 species, Australia and the surrounding area 26, North America 43 and South America a total of 62 species of large mammals.
The extinction of the large animals took place in virtually all climate zones and affected cold-adapted species such as woolly mammoths, temperate species such as forest elephants and giant deer, and tropical species such as giant cape buffalo and some giant sloths. It was observed on virtually every continent, although a particularly large number of animals became extinct in North and South America, where species including sabre-toothed cats, mastodons, giant sloths and giant armadillos disappeared, and in Australia, which lost animals such as giant kangaroos, giant wombats and marsupial lions. There were also fairly large losses in Europe and Asia, including a number of elephants, rhinoceroses and giant deer.
Weak climate effect
The results show that the correlation between climate change – i.e. the variation in temperature and precipitation between glacials and interglacials – and the loss of megafauna is weak, and can only be seen in one sub-region, namely Eurasia (Europe and Asia). “The significant loss of megafauna all over the world can therefore not be explained by climate change, even though it has definitely played a role as a driving force in changing the distribution of some species of animals. Reindeer and polar foxes were found in Central Europe during the Ice Age, for example, but they withdrew northwards as the climate became warmer,” says Postdoctoral Fellow Christopher Sandom, Aarhus University.
Extinction linked to humans
On the other hand, the results show a very strong correlation between the extinction and the history of human expansion. “We consistently find very large rates of extinction in areas where there had been no contact between wildlife and primitive human races, and which were suddenly confronted by fully developed modern humans (Homo sapiens). In general, at least 30% of the large species of animals disappeared from all such areas,” says Professor Jens-Christian Svenning, Aarhus University.
The researchers’ geographical analysis thereby points very strongly at humans as the cause of the loss of most of the large animals.
The results also draw a straight line from the prehistoric extinction of large animals via the historical regional or global extermination due to hunting (American bison, European bison, quagga, Eurasian wild horse or tarpan, and many others) to the current critical situation for a considerable number of large animals as a result of poaching and hunting (e.g. the rhino poaching epidemic).
The results have just been published in the article Global late Quaternary megafauna extinctions linked to humans, not climate change in Proceedings of the Royal Society B.
Don K says:
“Yes humans did wipe out the European Lion in historic times without firearms. But it took the Romans foraging for critters to stock the spectacles in the Coliseum to do it.”
No. The lion was already exterminated in most of Europe during the Ice Age. In Italy it survived until the early Holocene (about 10,000 years ago). In the Balkan peninsula and southern Ukraine it was exterminated during the Bronze Age and Early Iron Age (last known record I think is from the fifth century BC).
By the Roman Period the nearest lions to Rome were in Anatolia and North Africa.
rudy says:
“I believe that megafauna went extinct in Australia before the arrival of man..The synchroneity and rapidity of the Rancholabrean extinction also rules our human predation.”
The megafauna in Australia wnt extinct c. 40,000 years ago, when nothing much was happening climate-wise, but by an odd coincidence just as the first humans were spreading over the continent.
Talking about “Rancholabrean extinction” is rather silly since the Rancholabrean NALMA is a couple of hundred thousand years long. The megafaunal extinction happened quite quickly about 12-14 000 years ago in North America and a couple of thousand years later in South America, also just as humans were spreading over the continent in question.
Not in the West Indies, though, despite it being between North and South America. There the giant sloths survived until about 4,000 years ago. And then died out just as humans arrived there. Odd isn’t it?
And the mammoth survived on Wrangel’s Island until about 4,000 years ago, when the inuits happened to find the island.
And on New Zealand the giant Moas survived until about 500 years ago. The maori reached New Zealand about 1300 AD. And so on, and so on.
Steve P says:
June 5, 2014 at 9:27 am
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That evidence for mammoth huts is a thousand times better than your exaggerated link, and there’s more where that came from. (Can you tell me what happened to this vast repository of bones?) And how in the hell does a catastrophe pile up bones? Did you ever spend 10 seconds to ask that? There apparently are natural glacial processes that can bring about accretion of meteors and bones, and there certainly are places like La Brea tar pits and Hot Springs South Dakota where mammoth bones have accumulated for one reason or another, but these can in no way be correlated with catastrophe, but rather with climate in the Pleistocene and with man in the Holocene. Mammoth fossils are rare, and the idea that Paleolithic man learned how to make huts from such rare accumulations of fossil bones is absurd. And multiply that by the improbability of modern rediscovery of their ancient improbable find. The idea that they killed lots of animals in single herds, over and over again is the rational explanation. The YD catastrophists are worse at quantifying their theories than the climate catastrophists. –AGF
Dr. Strangelove says:
June 5, 2014 at 12:59 am
NZ Willy
“To make sense of your nonsense, how many species actually destroyed by man never to be seen again? Your tale is the favorite of tree-huggers. Man destroys the environment and all of man’s creations are evil. The poor sea cow was hunted to extinction but man produced over a billion cattle. They outnumber humans by weight. It must be bad because it’s man-made. We are giving man too much credit for extinction. We can’t even eradicate pests like cockroaches, termites, mosquitoes, rats with all our poisons. I suspect man will become extinct before cockroaches do.”
This article doesn’t say man is evil and the word ‘blame’ is a bit emotive and was not added by the authors of this study. The answer to those that ‘blame’ humans for existing is not to come up with the opposite view that we have no affect and can do as we chose. The Grand Banks were over fished and as a species we have devised ways of catching even more fish without considering there may be limits, in fact it is intelligent to understand what is possible and what is not possible and what is not a good idea. Blaming humans for existing is a bad idea but also over-fishing is a very bad idea and it is important to be able to discuss this and any other subject..
tty says:
June 5, 2014 at 10:30 am
Good points. Also the UK used to be home to Bears, Wolves, Lynx, Elk and Beaver. Their disappearance was not climate related.
It might be helpful to list the approximate times when megafaunal extinction occurred. Because it was NOT instantaneous and it was NOT synchronous. Instead it was a drawn-out process event though it was relatively abrupt in each area (and coincided with the first appearance of fully modern Homo sapiens in each area):
Australia and New Guinea c. 40,000 years ago
Southern Europe (mainland) c. 35-40,000 years ago
Japan c. 30,000 years ago
Northern and Eastern Europe c. 15,000 years ago
North America c. 13-15,000 years ago
Northern Siberia c. 11-13,000 years ago
South America c. 11-13,000 years ago
Cyprus c. 12,000 years ago
Corsica-Sardinia c. 11,000 years ago
West Indies 4-5,000 years ago
Wrangel’s land 4,000 years ago
Madagascar 1,000-2,000 years ago
New Zealand 500-700 years ago
No figures are available for India, southeast Asia and China. There was definitely a lot of megafaunal extinction there too, but it has not yet been reliably dated.
rudy says:
June 5, 2014 at 3:16 am
Nope. Australian extinctions are associated with arrival of humans, 40K to 60K years ago. Climate change can be ruled out:
http://www.nature.com/nature/journal/v445/n7126/abs/nature05471.html
It’s not mentioned in the abstract but the paper cites optically-stimulated luminescence & uranium-thorium dating of megafauna kills supporting the hypothesis that humans caused the Australian Pleistocene extinctions. The derived dates show mainland Australian megafauna going extinct rapidly around the same time, ~46,000 years ago, coincident with arrival of humans in numbers.
The Rancholabrean Age in North America lasted over 200,000 years, with the extinctions concentrated at its end, after humans show up. Coincidence? I think not.
tty says:
June 5, 2014 at 11:06 am
Same applies to Hawaii & other isolated oceanic islands.
agfosterjr says:
June 5, 2014 at 10:33 am
A thousand times better than Wiki, even?
http://en.wikipedia.org/wiki/Woolly_mammoth
I think a flood would do the trick, perhaps a continent-engulfing tsunami created by oceanic impact, or close passage of a large extraterrestrial body. Such might leave a whole range of confounding clues in the wake of its arrival or passage, but no direct evidence as to what it was. And there are other more down-to-earth(quake) mechanisms for tsunami,
Of course, that’s entirely wild speculation of my part, but I don’t think there is any question about the existence of the boneyards, both in Alaska, and also in Russia.
The mammoth huts were built from bones that were decades old. Archaeologists studying the huts found no evidence that the mammoths had been hunted, the bones were from mammoths whose bodies had fallen into to rivers, rotted away, the bones had washed down river and caught at bends where they washed up. Large numbers of bones accumulated over time later to be used as a handy source of building material for humans.
This particular theory has been around for a while. As have many others. Everyone likes there to be a nice simple answer for everything but this is rarely the case. For instance the extinction of the Dinosaurs. Heres a few theories , Asteroid impact, climate change, disiease, supervolcanoes, a nearby supernova, sea level rise, flowering plants. This is just a few. The most popular is the asteroid impact. There is large crater of the right date. However at the same period of time there were giant volcanic outpourings of basalt in what is now India. These are the Deccan traps. There is also evidence of sea levels rising dramatically and the climate changing. So what caused the extinction of the Dinosaurs ( and other animals and plants) was it one thing or a combination.
The same may well apply here. Man may just have been one of many things happening at the time that drove the mega fauna over the edge. During the paleolithic various hominids including us had to retreat before the advancing ice. Climate at the end of the last ice age was fluctuating, there is evidence of volcanic eruptions at about this time too. Sea level was rising, the English channel was completely formed as this time by a giant flood after an ice dam burst. A lot was going on.
Just a point about catastrophies. They did happen. Not in the Biblical sense though. There is evidence of asteroid/comet impacts. The earth has numerous craters one of the oldest is in Africa. Also nearby Supernova have exploded near Earth. Again there is geological evidence for this. There have been various giant basaltic volcanic eruptions that have spewed lava over vast areas. There has been extreme global warming and giant floods.
The Earth is an interesting and very dangerous place.
Steve P says:
June 5, 2014 at 11:23 am
Just as there are elephant bone yards today.
Often bone & fossil accumulations are because of current action or the animals’ dying around water holes or crossing rivers. But they also occur because of human hunting, as in sites around the world where prey species have been driven over cliffs or off hills & mountains. The Solutrean Culture in Europe is named after the site in France where horse herds were killed en masse for 25,000 years.
http://en.wikipedia.org/wiki/Rock_of_Solutr%C3%A9
Killing big game with spears now, to include Cape buffalo & elephants:
If you concentrate on cows & calves, as was common with bison hunters in North America, it doesn’t take long to wipe out a species with millions of members.
When rifle-armed hunters first appeared in Africa, the indigenous people thought that they were incredibly brave to hunt lions with firearms, since the matchlocks to which they were accustomed were far inferior to spears.
People all around the world get together for big game drives, using various techniques to channel stampeding herds into kill zones.
milodonharlani says:
June 5, 2014 at 11:53 am
I dunno about that. In the DeGannes Memoir at the Inoca Project/Parkland College link I gave above, we read:
~ continuing milodonharlani says:
June 5, 2014 at 11:53 am
But as the above accounts make clear, buffalo & other game were abundant in N. America. It may be that the natives would have wiped out the bison eventually, even without firearms, and even if the Europeans had never made landfall in N. America, but direct accounts from that period testify to the abundance of game, despite the very successful hunting efforts of the natives that are described.
And as far as the idea that megafauna of N. America were especially vulnerable to the newly arriving humans goes, the tactics required by the native peoples to hunt these beasts shows that the prey were suitably wary of humans. DeGannes did mention a type of muskrat that was easy to approach, and club to death, but the deer and buffalo required rather more finesse.
Steve P says:
June 5, 2014 at 12:41 pm
You miss the point about naivety. The bison hunted in historical times had lived with Indians for thousands of years. They were the survivors of the Megafaunal Blitzkrieg of before 10,000 years ago.
Plains Indians did indeed concentrate on bison cows, as did the market hunters who almost wiped them out in a decade. The Illini didn’t like calves, but woodland bison in the East still managed to get wiped out, largely before European contact. Once you kill off the cows, nursing calves die anyway.
Before horses, Plains Indians & Archaic Indians simply stampeded all bison, bulls, cows & calves over cliffs, which is how all but the surviving smaller species were driven to extinction.
http://www.emporia.edu/cgps/tales/bison.html
Wherever humans found naive big game species, they killed them off, whether mammoths or moas, Australia or America. When human numbers got large enough, even animals acclimated to people also perished.
Whether through hunting, habitat destruction, disease or other means, we have been death to isolated, vulnerable or naive populations of meaty animals with slow reproduction rates. Even in Europe & Asia, anatomically modern humans managed to wipe out the megafauna which had survived prior interglacial periods.
surely it is time to cease all “sports” hunting.
Mankind has moved on from the “Hunter Gatherer” phase. Celebrating “the gun” and “the itrepid hunter” as is rife in the USA with the exzcpetion of commonsense culls is not only barbaric, it is plain stupid
Steve P says:
June 5, 2014 at 11:23 am
Two problems:
1) Your Wiki link provides no source for these disparate dates of mammoth hut bones.
2) If they are correct, that requires that the bones were never used for fuel over the time span indicated.
Someone directed me to some early and reliable bone yard anecdote two or three years ago here at WUWT, and as per your source, an accumulation of over 200ky is indicated–no catastrophe. The blood antifreeze is typical Wikipedia nonsense. For something still unscholarly but less nonsensical see:
http://www.afghanchamber.com/history/stoneages.htm
…with the humorous line: “Remains suggest that some of them ate nothing but mammoth meat. They must have been delicious, since they ate every last one.”
So we can agree that lots of mammoths lived for a long time and their tusks were usually preserved, their skeletons much of the time, and occasionally their hide and even softer tissue. Asian mammoths coexisted with humans for thousands of years, and American mammoths for hundreds of years. Yes, the meat was good.
As for catastrophes, I’m pretty sure the tendency was for the evidence to be scattered rather than gathered–or so the laws of thermodynamics. –AGF
cnxtim says:
June 5, 2014 at 1:08 pm
Most “sport” hunters & fishers eat their kills. I was raised on shot & caught deer, elk, pheasant, trout & salmon.
Hunting is an essential wildlife management tool, now that so many natural predators of game species have been greatly reduced or wiped out.
Many sport hunting & fishing species have been introduced & aren’t natural.
Here’s the best link I’ve found so far, but the out links are paywalled: http://archaeology.about.com/od/ancienthouses/g/mammoth_huts.htm
–AGF
If humans are responsible fore their demise, where are the big piles of mammoth and mastodon bones with marks consistent with butchering?
Did humans chow down on the Dire Wolf, Cave Lion, and Short-faced Bear too?
If H. sapiens was responsible for exterminating so many creatures, we should expect to see an abundance of clear and unambiguous evidence attesting to that enormous slaughter,
Instead, virtually zip.
Show us the bones.
milodonharlani says:
June 5, 2014 at 11:18 am
The derived dates show mainland Australian megafauna going extinct rapidly around the same time, ~46,000 years ago, coincident with arrival of humans in numbers.
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Why did humans show up then? It can be easily understood that the same climate change that killed the megafauna made the environment suitable for human habitation. Correlation doesn’t prove causation.
Steve P says:
June 5, 2014 at 4:14 pm
There is lots of evidence, much cited here already. I wonder if you have read the comments.
Cave lions were in Europe, not the Americas. Dire wolf & short-faced bear died out for lack of their usual prey species, killed off by humans, but they & their young would also have been targeted for death by people, just as Americans extirpated wolves from the West.
The bones of mammoths & other megafauna killed by humans over a millennium or more were mostly scavenged or not preserved, but at kill sites across the continent there are signs of human predation & butchering. Bear in mind that Woolly & Columbian mammoths were not numerous.
Here again are some sites:
http://en.wikipedia.org/wiki/Lehner_Mammoth-Kill_Site
http://en.wikipedia.org/wiki/Naco-Mammoth_Kill_Site
http://nativeamericannetroots.net/diary/904
“Clovis hunters understood that large mammals, such as the mammoth, had to have water: thus, they could be found at watering holes and ponds. Furthermore, they understood that the soft ground near the watering holes could slow the animals down and would sometimes entrap the large mammals. At a Clovis mammoth kill site in Wyoming, archaeologists feel that the evidence shows that the hunters ambushed the animals and then drove the panic-stricken animals into the muck. At Murray Springs, near present day Tombstone, Arizona, Clovis hunters ambushed bison around a small pond. Then the hunters set up a camp on a nearby high spot where the animals were butchered.
“At the Colby site, near Worland, Wyoming, Clovis hunters 12,000 years ago killed several mammoths in a shallow arroyo. The hunt probably took place in the late fall or early winter. The hunters partly butchered the animals, then stacked the carcasses into piles to be frozen. The hunters then moved on, returning to open the cache when they needed meat. In other words, Clovis hunters understood the basic principles of freezing and used frozen meat caches.”
A possible Woolly kill:
http://old.post-gazette.com/healthscience/20000228woolly2.asp
Lots and lots of very loose logic above which folks are trying to pass off as some sort of science.
If man eliminated mega fauna, it was a pretty amazing trick since mega fauna were well established around the world, while man was still trying to spread out.
According to the ‘blame mankind’ science wonders mankind killed mega fauna throughout North and South America when man had immense problems surviving in very large areas during that so-called extinction period.
Life was already extremely dangerous and it was not smart to make very dangerous hunts a regular event.
Find a dead mega fauna? Well, food is where you find it and man was a scavenger that survived scavenging by cooking.
Maori feasts? Great piles of bones? That is evidence of people looking to stuff themselves at a temporary camp, not predators living in a confined area.
Yum? Barbecue? Even primitive man understood that winter followed summer and fall. Putting up food for the winter was an urgency generally followed by colonies of mankind and began as soon as spring arrived.
Putting up food for multiple years is relatively irrational as primitive man had minimal protections from insects and vermin. Even very hungry hunter/gatherers had difficulty getting excited about two-three year old dried meat. Which is a good reason to work more on developing grains, fruits, tubers and vegetables. Especially the long storing kind.
Most hunter/gatherer groups did not harvest more than they needed.
Hunting the next size down critters is plenty dangerous enough for primitives. Wounding a pig, bison or bear for example was a very bad idea. Watch the Smithsonian channel and while ignoring their anthropomorphic slant and constant AGW bleating, observe the animals. Watch the bison kick a wolf ass over teacups, ditto for the giraffe; notice how an elk slams into a grizzly bear and shoves it back a significant distance.
Thinking that hunting these animals is slam dunk easy is a sign that someone strictly buys their food wrapped in plastic.
Want to engage a seriously dangerous wild animal even with modern firearms to check just how dangerous they are and how easy to hunt? Buy a guided hunt for cape buffalo, lion, leopard, tiger, brown bear, polar bear… Even today with modern firearms people get mauled, maimed and sometimes killed while trying to hunt these critters.
Oh, but the mega fauna were people stupid. Say what? Just what is people stupid? Do you really believe that people fresh to an area could just dance their way up to a mastodon and stick a spear in it? That would be a definitive Darwin award effort; can you spell ‘people jam’? Or perhaps you meant that primitive man snuck up on a saber tooth tiger, American cave lion, short faced bear or Eurasian cave lion and poked them with a sharp stick?
Maybe you meant that one of your little group drew the short straw that year and had to be the one to tempt one of these mega fauna to chase them to a pit with a sharp stick in the bottom? How big is that pit and just how is the pit constructed? Big cats have phenomenal jumping ability, not forgetting sprinting.
Primitives who had access to easy meat, e.g. Plains Tribes, frequently hunted them for winter stores. Regular life was focused on smaller critters with rabbits and birds being very popular. Early nets were woven to capture both rodentia and birds when driven with entire tribes engaged in the hunt. Rabbit skins were cut into strips and then woven into blankets; very soft and quite warm. Large animal skins, e.g. bison, were used for shelters, e.g. teepee. Small critters were very preferential for regular food as anyone, even kids with bent sticks, could hunt them safely. Many primitive peoples were transitory moving to a new camp when local small critters were getting scarce.
Even in Colonial America, squirrels were the most common meat where ‘barking a squirrel’ meant an accurate shot that killed squirrels by impact shock rather than bullet damage; it took accurate shot placement just into the wood next to where the squirrel was holding.
It seems that every time I read one of the so called research cited as ‘proof’ that mankind decimated mega fauna, I am struck by how the researchers sought evidence for proof for their assumptions rather than overwhelming evidence driving the idea.
Think different about it? Fine, prove it. Yeah, points have been found in critters, but we do not know why. Those points could be near misses from some other tribe trying to steal the found kill. Cut marks are common on bones; well yeah, man was happy to get meat and often even happier to get a source of large tendons. Tendons are the source of sinew used for bowstrings and wraps. Tendons and sinew were also used in gluing up more powerful weapons like laminated recurve bows, (e.g. used by Native Americans and Scythians) or making the notches fir atlatls.
Remember Ötzi the iceman found in the Alps; he was found with an arrowhead in him. The arrowhead killed him, but not immediately. Getting shot with an arrow usually means death by blood loss, as in Ötzi’s case; mega fauna can do a lot of damage before succumbing.
“…making the notches fir atlatls…”
should be
“…making the notches for atlatls…”
Finger transcription clumsy here.
milodonharlani says:
June 5, 2014 at 4:27 pm
http://en.wikipedia.org/wiki/American_lion
Three kill sites do not amount to much against the backdrop of the Late Pleistocene extinction event.
ATheoK says:
June 5, 2014 at 4:51 pm
“Most hunter/gatherer groups did not harvest more than they needed.”
Sorry, but that is so wrong as to make me laugh out loud. Hunter-gatherers often waste more than they use.
The overwhelming evidence of its falseness lies on every continent.
http://en.wikipedia.org/wiki/Buffalo_jump
http://en.wikipedia.org/wiki/Rock_of_Solutr%C3%A9#Hunting_site
Don’t know what logic you find faulty, but the association of human arrival with mass extinctions in the Americas, Australia, New Zealand & other islands is not a coincidence. It doesn’t have to be from hunting alone. At least a dozen bird species died out in the Hawaiian Islands from the effects of farming as well as hunting after the Polynesians arrived. That Pleistocene megafauna in Europe & Asia which had survived prior interglacials also went extinct during the Holocene is due to hunting by better equipped & more numerous anatomically modern humans, rather than sparse & less advanced Neanderthals. Our projectile weapons were far more effective & safer against big game than Neanderthal thrusting spears.