'Climate Disruption' of the past seen in mummy DNA

One of the favorite boogeyman arguments used in climate alarmism is that climate has been stable for thousands of years, and that our recent industrialized era emissions will result in climate tipping point. However, this study in the Proceeding of the National Academies of Science suggest that climate disruption caused people in the Central Andes to migrate to find a better climate over a thousand years ago.

Source: Modern Records of Atmospheric Carbon Dioxide (CO2) and a 2000-year Ice-core Record from Law Dome, Antarctica CDIAC -click

This posited bout of climatic fluctuation occurred before anyone knew what carbon dioxide was. So what was the driver then? Surely it wasn’t CO2 levels, which according to James Hansen and Bill McKibben who say“safe” levels are below 350 parts per million, which according to this graph from CDIAC, was below 300ppm during the period of study.

The paper: 

Climate change underlies global demographic, genetic, and cultural transitions in pre-Columbian southern Peru, Lars Fehren-Schmitz, PNAS, doi: 10.1073/pnas.1403466111


It has long been assumed that climate played a major role in the population history of the Central Andes. Although adaptations of the Andean populations to climatic changes such as the intensification of agriculture have been inferred from the archaeological record, evidence for demographic adaptations such as migration is missing so far. In this paper, ancient DNA data from populations that lived in southern Peru between 840 BC and 1450 AD provide evidence for two large-scale migrations in the Central Andes coincident with episodes of drought and increased climatic variability. These migrations led to a successive genetic homogenization of southern Peruvian populations generally attributed to intrusions by the late pre-Columbian highland empires such as the Wari, Tiwanaku, or Inca.


Several archaeological studies in the Central Andes have pointed at the temporal coincidence of climatic fluctuations (both long- and short-term) and episodes of cultural transition and changes of socioeconomic structures throughout the pre-Columbian period. Although most scholars explain the connection between environmental and cultural changes by the impact of climatic alterations on the capacities of the ecosystems inhabited by pre-Columbian cultures, direct evidence for assumed demographic consequences is missing so far. In this study, we address directly the impact of climatic changes on the spatial population dynamics of the Central Andes. We use a large dataset of pre-Columbian mitochondrial DNA sequences from the northern Rio Grande de Nasca drainage (RGND) in southern Peru, dating from ∼840 BC to 1450 AD. Alternative demographic scenarios are tested using Bayesian serial coalescent simulations in an approximate Bayesian computational framework. Our results indicate migrations from the lower coastal valleys of southern Peru into the Andean highlands coincident with increasing climate variability at the end of the Nasca culture at ∼640 AD. We also find support for a back-migration from the highlands to the coast coincident with droughts in the southeastern Andean highlands and improvement of climatic conditions on the coast after the decline of the Wari and Tiwanaku empires (∼1200 AD), leading to a genetic homogenization in the RGND and probably southern Peru as a whole.

Source: http://www.pnas.org/content/early/2014/06/11/1403466111.abstract

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June 18, 2014 10:03 am

IN other words: they adapted. What a radical concept!

June 18, 2014 10:14 am

Isn’t that an old Sam Kinnison joke? “Move to WHERE THE FOOD IS!”

Gary Pearse
June 18, 2014 10:22 am

640 AD: the Dark Ages cold period; 1200Ad the Medieval warm period in the Southern Hemisphere!

Alan Watt, Climate Denialist Level 7
June 18, 2014 10:26 am

So maybe these were really the “first climate change refugees” ?

June 18, 2014 10:28 am

climate science 101. any climate change that can’t be attributed to humans must be due to volcanoes. we can tell how big the volcanoes must have been by how much climate change there was. In this case a big volcano must have started erupting in ∼640 AD and ended in ∼1200 AD. the cannot be connected to the medieval warm period, because this change in south America, as well as the change in Europe, even thought they were at similar times, were both only regional. global changes only occur when humans are involved.

June 18, 2014 10:33 am

Since the Little Ice Age in Europe was coincident with the 30 Years War, these findings should not be unexpected. The 30 Years War ended with the Treaty of Westphalia. This treaty created the concept of the sovereign nation state which shapes our world today. So it is no surprise that climate change can have dramatic and long lasting political and societal effects.
One thing that we should all remember the CO2 or not, climate plays an important part in our history and that even relatively slight climate changes can have large effects. natural variability can drive the course of history fro centuries. Don’t let the hype from climate activists and third team activist scientists distract us from this fact.

June 18, 2014 10:39 am

This is a Wikipedia article on the chaos that gripped Europe in the 17th century coincident with the climate change of teh LIA

June 18, 2014 10:47 am

No surprise that in the past two decades scientists and archaeologists have sought other explanations than climate change for the collapse of the North American Anasazi and Mississippian and Central American Classic Maya civilizations.

June 18, 2014 10:49 am

After approximately 1150, North America experienced significant climatic change in the form of a 300-year drought called the Great Drought. This also led to the collapse of the Tiwanaku civilization around Lake Titicaca in present-day Bolivia.[22] The contemporary Mississippian culture also collapsed during this period. Confirming evidence is found in excavations of the western regions of the Mississippi Valley between 1150 and 1350, which show long-lasting patterns of warmer, wetter winters and cooler, drier summers. http://en.wikipedia.org/wiki/Anasazi
Yep, only now do we see climate causing any problems for the human race. Is history unknown to alarmist?

June 18, 2014 10:57 am

TAG says:
June 18, 2014 at 10:39 am
That societal decline is associated with cool periods is no coincidence, IMO. Examples include not only the AD 17th century during the LIA but prior cold centuries called the Dark Ages or Migrations Period, which preceded the Medieval Warm Period, during which population grew and culture flourished. Another is the so-called Greek Dark Ages, which followed the Minoan Warm Period of high culture and preceded the Roman Warm Period, which was followed by the Migrations Cold Period.

Chris B
June 18, 2014 10:59 am

I’d like a couple million and a super computer to find out where all the SUV’s and coal plants went.

June 18, 2014 11:01 am

If it doesn’t fit the agenda it is irrelevant.

June 18, 2014 11:14 am

I am old enough to remember when anti-Cold War academics blamed the collapse of Mayan civilization on warfare and militarism. When environmentalism became orthodoxy, the Mayans must have used up all the available natural resources.
Now the best answer for dramatic political and social change 700 and 1400 years ago appears to be climate-related (looks like every 20th ENSO cycle or so is a real b*tch). But there is no way to blame humans for that and worse, it suggests that CO2 does not explain all so I guess we will have to declare these big historical changes a mystery until there is a theory that can be made to serve some au courant ideological purpose.

June 18, 2014 11:15 am

In the last years of the 1200s a drought drove the Indians out of Mesa Verde, Colorado and the Mound Builders north of today’s Houston to another area. They both lived near rivers or creeks. At the same time there was a recorded drought in England.

June 18, 2014 11:19 am

Here is what climate disruption can do.

Man and Environment in the Eastern Atacama Desert (Southern Peru): Holocene Climate Changes and Their Impact on Pre-Columbian Cultures
……A new hydrological oscillation took place after ∼1100 AD. Monsoonal rains reached the Andean foreland again and narrowed the desert to ∼40 km. During the following Late Intermediate Period (LIP), pre-Columbian people re-occupied the eastern Atacama desert until the sixteenth century AD. The Little Ice Age, with its coldest temperatures between the seventeenth and nineteenth centuries AD, was a very dry period in the study area, so that LIP settlements were abandoned and desert conditions reappeared lasting until today.

Now if we can just get back to that wonderful 300 ppm of carbon dioxide. We can fix temperature to a safe level again.
Below are some of the effects of the Little Ice Age on humanity from the literature.
Crop failures, hunger, mass migration, epidemics, great storms in the North Atlantic, Europe wide witch hunts, endemic Malaria in England & part of the Arctic Circle, higher wildfire frequency in circumboreal forests, strong droughts in central Africa (1400–1750), social unrest in China, dead Central American coral reef, century-scale droughts in East Africa, large increases in flood magnitude (upper Mississippi tributaries), environmental and economic deterioration in Norway, decline in average height of Northern European men, climate became drier on the Yucatan Peninsula, sudden and catastrophic end of the Norse Western Settlement in Greenland, River Thames freeze-overs, agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century.

June 18, 2014 11:33 am

Another thing to notice here is that Climate is Regional. It isn’t some global anomaly or any other global metric.

June 18, 2014 11:39 am

“episodes of drought and increased climatic variability”? I always thought that drought referred to periods with a pronounced LACK of variability in humidity.

June 18, 2014 11:39 am

The alarmist response to this would be that they know climate has changed in the past. Then they will say past changes are irrelevant to the current situation because the rate of rise in carbon dioxide in the atmosphere is unprecedented and the current changes in the climate are far more rapid than have ever occurred. I don’t buy the “we know the climate has changed in the past, but now it is different and spells the impending doom of civilization as we know it” argument but it inevitably comes up in light of information like in this study….

June 18, 2014 12:19 pm

Here is what climate disruption did during the peak of the Holocene climatic optimum (Altithermal).
Highly efficient hunters, climate change and possibly epizootic diseases accelerated the extinction of mammoth, giant sloth, horse, camel and other large animals. Through all of this humans and their prey adapted to the gradually warming climate until about eight thousand years ago, when a dramatic climatic upheaval occurred: the Altithermal.
Drought after drought baked North America, lowering regional water tables as much as twenty feet.Vegetation zones shifted, topsoil eroded cutting deep channels into the earth. Tree lines climbed higher on the mountains. The largest body of water in North America, the Great Basin disappeared: leaving salt flats and desert Utah and Nevada. Great dune fields spawned from the droughts and drifted to cover parts of Montana, Wyoming and Nebraska.
It was a period of severe hardship in which people starved, hunters turned warriors warred with other tribes and villages. They moved often in search of the elusive herds of game animals. But people adapted: these harsh times gave birth to the new culture of North America.

June 18, 2014 12:46 pm

We humans have a skewed perception of things for the simple reason that for our entire existence as a species we have known nothing but ‘Ice House Earth’. With a thermalneutral point of around 82F we are meant for ‘Green House Earth’, the condition most prevalent during the past for many millions of years. To compensate for our lack of natural endowments suited to the present climate we spend most of our time and effort acquiring shelter, clothing, heat and so forth. Houses, cities, highways, oil tankers and pipelines, all of modern civilization is man’s adaptation to living in an ice age. How would we have adapted differently to Green House Earth?

June 18, 2014 12:52 pm

Genghis says:
June 18, 2014 at 11:33 am
Another thing to notice here is that Climate is Regional. It isn’t some global anomaly or any other global metric.
That’s what the alarmists say. Here are some glaciologists who say different:

Robert W Turner
June 18, 2014 2:13 pm

Seeing a compilation of climate’s affect on human populations during the Holocene would be very interesting and if were in simple video format on Youtube then it would help put an end to the Holocene climate stability meme.
Mass migrations out of the Sahara when it underwent desertification coinciding with the rise of the Egyptian empire, abandonment of Native American settlements in central and southwest North America coinciding with drought, three (I think) periods of settlement on Greenland which flourished and then disappeared due to warming and cooling of the North Atlantic, collapse of the Indus Valley civilizations, the list just goes on and on. The memes on which CAGW are built on need to be deconstructed in public view.

June 18, 2014 2:13 pm

agfosterjr; That’s what the alarmists say. Here are some glaciologists who say different:
I think you misunderstood me. The term “Global Climate” is meaningless as is the term Global Temperature or Global Anomaly. Climate is the general weather pattern in some region, say the South Pacific or a Boreal forest, or the Arctic or the Sahara.
It makes no sense at all to average temperatures from around the globe and proclaim it the Global Climate. Unless you have an agenda of course.
What the alarmists are doing is data mining until they create or find a trend that suits their purpose, then they proclaim that the sky is falling.
Climates are always changing, but we have a better word for it, evolution.

June 18, 2014 4:52 pm

The Little Ice Age, with its coldest temperatures between the seventeenth and nineteenth centuries AD, was a very dry period in the study area, so that LIP settlements were abandoned and desert conditions reappeared lasting until today.
With desert conditions “lasting until today”, that argues that the LIA never ended in 1850. Rather our temperature increase over the last 150 years is simply a continued recovery from a colder/dryer climate 300 years ago.

Gunga Din
June 18, 2014 7:02 pm

I guess the “new normal” isn’t so new after all.

June 18, 2014 11:04 pm

The BBC ran a documentary last night about ‘Bog Bodies’..over 300 found to date of people murdered as sacrifices and buried in Bogs across northern Europe from Ireland to Scandinavia. The bodies are remarkebly well preserved by the acid condition of the peat bog. There was a peak of such sacrifices c. 700 to 200 BC and it has been discovered from analysis of different types of Amoeba from the peat that during this time climate was much cooler and wetter than before this time and afterwards, causing poor harvests. Hence (it was argued) the spike in sacrifices to appease the deities controling the weather. Another BBC doc. talking openly about pre-industrialisation climate change…are they letting their guard down?

Village Idiot
June 18, 2014 11:20 pm

“[Our] favorite [strawman] arguments used [against] climate alarmism is that climate has been stable for thousands of years”
“However, this study in the Proceeding of the National Academies of Science suggest that climate disruption caused people in the Central Andes to migrate to find a better climate over a thousand years ago.”
Strawman decapitated!

Joel O'Bryan
June 18, 2014 11:22 pm

The Anasazi of Mesa Verde Colorado abruptly abandoned their mesa top cliff dwellings around 1250AD. It is speculated that a warm period from 800-1250 AD allowed this agrarian civilization, based on maize cultivation on the plateau, allowed the complex society to grow at 7500-8000feet. But hen the climate changed and abruptly the growing season became too short on the plateau for reliable maize harvests. Starvation set in, the society collapsed, and the population dispersed across the SW US at lower elevations where it was warmer.
Around 1000AD Norse colonies on Greenland were setup and thrived until the climate grew dramatically colder and sea ice became year around. The Greenland colnies seemingly collapsed overnight, just like the Anasazi.
Those are realities that the CAGW Alarmists do not want people to know about.

Steve P
June 19, 2014 12:11 am

Climate alarmism is denial of natural climate change. Because climate change is natural, there is no reason for alarm, hysteria, or panic.
In particular, panic about potentially warmer conditions would seem to be the epitome of human folly, because it is the cold we should fear, but perhaps it is also a perfect metaphor for the foolish age in which we live, where the swindlers have not only figured out a way to tax the air we breathe, but have also recruited an army of true believers who are convinced warmer is worrying, and think we should let the scammers take our money, and who readily trot out the denier label to apply to skeptics, unaware seemingly that they themselves are in denial of natural climate change, and are therefore hoist by their own petard.
Denial of natural climate change: my, how the tables can turn.

John Gorter
June 19, 2014 5:21 am

You may want to look at the series ‘A short history of the human race’ by Ed Caryl on No Tricks Zone blog. 4 parts so far, interesting compilation on the theme of climate and human civilisations.
John Gorter

June 19, 2014 6:17 am

Genghis says:
June 18, 2014 at 2:13 pm
Like the alarmists, you are denying a global WMP and LIA, to which I say, BS. –AGF

June 20, 2014 7:47 am

Is it just me, or was Greenland named because of all the ice and snow – perhaps it’s because it used to be green!

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