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