Tuesday, May 2, 2017

Caspian Steppe Dustbowl

Below is linked a paper on the paleoecology of the Caspian Steppe.  The process of aridization can be viewed partly from the isotopes taken from those people.  The chronology in table 1 tells us why people began moving out of this area.

But first, in order to appreciate what aridization meant to the actual human beings that lived on the steppe of that time, I've linked a trailer to a series called "The Dust Bowl" by Ken Burns on PBS. 

The dust bowl was an environmental catastrophe.  Not as bad as this man-made disaster, though

Chatter networks informed people of prospects in other places.  Moving into Europe would have been a rather bold move, so I wouldn't call them hapless refugees.  They needed land, Europe had land.


Shishlina, Zazovskaya, VanderPlicht, Hedges, Sevastyanov, Chickagova
RADIOCARBON, Vol 51, Nr 2, 2009, p 481–499 [Link]
ABSTRACT. Combined analysis of paleoenvironment, 13C, 15N, and 14C in bone, including paired dating of human bone and terrestrial materials (herbivore bone, wood, charcoal, and textile) has been performed on many samples excavated from Russian
kurgan graves. The data can be used for dietary reconstruction, and reservoir corrections for 14C dating of human bone.  The latter is essential for an accurate construction of chronologies for the Eneolithic and Bronze Age cultures of the Caspian


  1. The table shows a favorable climate from 4300 to 2600 BCE. Then:

    2600–2300 cal BC

    Abrupt aridization; summer temperature increased and winter temperature became lower, and the amount of pre-cipitation decreased; dry steppes were replaced with semi-desert landscapes, characterized by wormwood and fescue corresponding to a very dry climate; the forest area over ravines was reduced; the annual precipitation was 40–60 mm lower than today, and 140–160 lower than it was during the previous period.

    Late Yamnaya, Steppe North Caucasus, Early Cata-comb, and Early East Manych Cata-comb

    2300–2000 cal BC

    Continuation of the aridization, predominance of semi-desert landscapes, further reduction of forest areas.

    East Manych Catacomb and Lola

    1. It looks a drought started before this, around the turn of the 3rd mil. But around 2600 is the turning point.

      I tried to find a more detailed geological history of the Caspian steppe, but it's probably in Russian only.

    2. Correct me if I'm wrong, but what your implying isn't correct because (1) there wasn't a migration from caspian steppe and (2) this aridization event occurred too late anyhow for the alleged non-migration :)

    3. 2600 is the environmental choke point, but aridization had already begun in the second half of the third millennium (table 1).

      The area discussed is actually the Black Sea-Caspian sub-steppe north of the Caucasus and up to the waist of the Volga and Don.

    4. Worth noting that the 4.2 kya event (which these data points reflect with regional variation and a spread around the peak in time) probably spanned from India to Spain and everywhere remotely in between (FWIW California got a brief respite from its megadrought at the same time IIRC). It made the Sarasvati River go dry. It killed the Akkadian Empire. It caused the collapse of an Egyptian Dynasty giving rise to an Intermediate Period. This is also to be the time period during which the pork taboo shared by Jews and Muslims today came into being.

      While the steppe become less habitable, places that used to have a different ecology than the steppe because they had more precipitation dried out and become more steppe-like, leaving steppe people better adapted to living there than the existing occupants whose farming and herding techniques weren't optimized for drier climes.

    5. David Anthony implicated the 5.9 kilo year event that began migration out of the steppe. Probably both environmental events impacted the region

    6. Hhm. But it really seems that 300->2500 BC was the fluorescence of the steppe Yamnaya culture: the most number of finds, etc; even active colonisation of the steppe. People weren't fleeing from it, but moving onto it. Of course, maybe it got too crowded and some moved instead north and west

    7. Good point, but I'd argue that a population decline could also reinvigorate a culture. ie. Black Death in Italy

    8. Which population decline ?
      3000-2600 was a relative optimum with the "opening up" of the steppe, thanks also to wagons etc .
      The "decline" occurs after 2500Bc, which sees the disappearance of kurgans from Central and southeastern Europe, and their concentration back in the Pontic steppe itself, transitioning to the Catacomb period.

  2. If you want a really juicy potential connection, the Younger Dryas comet event theory which dates that event to ca. 10890 BCE to 10950 BCE, as part of coherent cataclysm theory also suggests that the same comet spawned Taurid meteor shower should also trigger a high risk of large comet-like impacts roughly every 6,000 years for a roughly 20,000-30,000 year period. Hence, a similar impact could have contributed to the LGM and another similar one could have contributed to one of the climate events we are discussing here, and yet a third additional one due in the next 1,000 to 2,000 years or so. So, if global warming gets out of hand, we may have a comet to right it in reasonably short order for a thousand or two years.