Scientists finally know what stopped Mongol hordes from conquering Europe

[HiThere]

The Mongols gave up on their conquest because of abrupt climate change?


http://www.businessinsider.com/climate-change-stopped-khan-european-invasion-2016-5?r=US&IR=T&IR=T

 

[Eboard10]

Very interesting, thanks for sharing Hithere.

The time period in question roughly coincides with the sudden disappearance of the Paleo Eskimo culture some 700 years ago, which was asked in a past session.

(Andromeda) I don't have a pressing one, but I have a non-current event one. These Dorset people, the Paleo-Eskimos that disappeared 700 years ago... Apparently, they were an isolated genetic group for about 4000 years – they inbred and didn’t out-breed; then they disappeared all of a sudden. What happened to them?

A: Check the strong signal in the ice cores. Think of a blast of cold that was not survivable.

Q: (Perceval) “The Day After Tomorrow”...

A: Close.

This abrupt climate change might be related to the spike in the ice-core signals recorded around 1259 AD:

_http://climate.envsci.rutgers.edu/IVI2/

_http://onlinelibrary.wiley.com/doi/10.1029/95JD01751/abstract

The high-resolution and lengthy records of volcanic aerosol deposition in ice cores allow assessment of the atmospheric impact of different styles and magnitudes of past eruptions and the impact of volcanism during periods of varied climatic conditions. The 2100-year long volcanic SO42− time series in the Greenland Ice Sheet Project 2 (GISP2) ice core was used to calculate the mass stratospheric loading (MD) of H2SO4 and resulting optical depth values (τD = MD/1.5 × 1014 g) for individual, and multiple, closely spaced eruptions. Calibration of the calculated optical depth values with other compilations spanning the last 150 years provides a range of values for each eruption or set of eruptions essential to quantifying the climate forcing capabilities of each of these events. Limitations on the use of the results exist because this is only a single ice core, sampling was biannual and transport, and deposition of aerosols is not consistent among individual eruptions. The record of volcanic optical depth estimates is characterized by distinct trends within three consecutive 700-year time periods. The period from 100 B.C. to A.D. 600 is characterized by the fewest eruptions, and optical depth values are lower than those in the rest of the record. The exception is an extremely large signal of 3 years duration that is probably associated with an unknown Icelandic eruption around 53 B.C., with the possible contribution of another high-latitude eruption. The presence of another signal at 43 B.C. suggests that at least two eruptions impacted climate in the middle decade of the 1st century B.C. The period from A.D. 600 to 1300 has intermediate numbers and magnitudes of volcanic events except for the very large 1259 event. Stratospheric loading and optical depths values for the 1259 event are twice that for Tambora (A.D. 1815). The state of the climate system in the middle of the thirteenth century A.D. may not have been sensitive enough to the atmospheric perturbation of the 1259 eruption, thus the apparent lack of abundant proxy evidence of climatic cooling around A.D. 1260. The most recent 700 years (A.D. 1400–1985) are characterized by the greatest number of eruptions (half of those recorded over the 2100 years of record) and, in general, the highest stratospheric loading and optical depth values for individual and the combined effects of multiple eruptions. The large Kuwae eruption (A.D. 1450s) may have perturbed the atmosphere at least as much as Krakatau and possibly of a magnitude similar to Tambora. Multiple eruptions in the 50-to 60-year periods from A.D. 1580s–1640s and A.D. 1780s–1830s may have had a significant impact on enhancing the already cool climatic conditions in those time periods, particularly around A.D. 1601 and 1641. These findings imply that multiple eruptions closely spaced in time are more likely to have a major impact on a decadal time scale when existing climatic conditions are in a more sensitive or transitional state. The GISP2 ice core record also indicates that several relatively unknown eruptions may have been large sulfur producers during the 17th and 19th centuries A.D., thereby warranting further studies of those particular events.

 

[Niall]

The problem with 'scientists'...

Wet Climate May Have Fueled Mongol Invasion

...is that they often cancel each other out!

Yes, ca. 1200 is considered the 'end of the Medieval Warm Period' and the descent into 'the Little Ice Age', and thus a turning point in global climate. But for the time period in question - early to mid 13th century - although climate could well have been a factor in that particular episode (the Mongols returning from Europe), it wasn't until a century later that everything went for kaflooey (for the Mongols and everyone else) with the arrival of 'the Black Death', beginning ca. mid-14th century.

Plague seems to be the climate's primary, or most significant, contribution to the fall of systems/civilizations, and it seems to always arrive after a build-up of increasingly crazy weather, planetary upheaval, and cometary activity.

The BI article you linked to concludes by saying that

"[this] also hints at a lesson for our climate future: A relatively small difference is all it takes to change the course of human history."

That's not quite what we've found in our research. As I alluded to above, relatively local changes in climate patterns (even if they are temporarily disastrous for the region) may be a factor in directing armies one way or the other - or, today, forcing the relocation of tens of thousands of people - but it is catastrophic climate change that changes the course of human history by forcing a complete system/civilization 're-set'.