Tuesday, February 18, 2020

Ancient DNA from 14th Century Black Death Grave Supports Paradigm

The discovery of mass burial sites is rare in Europe, particularly in rural areas. Recent excavations at Thornton Abbey in Lincolnshire have revealed a previously unknown catastrophic mass grave containing the remains of at least 48 men, women and children, with radiocarbon dating placing the event in the fourteenth century AD. The positive identification of Yersinia pestis in sampled skeletal remains suggests that the burial population died from the Black Death. This site represents the first Black Death mass grave found in Britain in a non-urban context, and provides unique evidence for the devastating impact of this epidemic on a small rural community.
Willmott, et al., "A Black Death mass grave at Thornton Abbey: the discovery and fourteenth-century rural catastrophe", 94 (373) Antiquity 179-196 (February 18, 2020).

Nothing in this paper really changes the big story of the black plague in Medieval Europe or England. Instead, it reaffirms the paradigm and fills in gaps that were strongly expected to exist already (the existence of rural mass graves in England). 

But, corroboration of the existing paradigm is also important as it enhances the reliability and robustness of conclusions reached after the ground breaking discoveries and insights are made.

The Black Death, The Great Famine And The Little Ice Age
In less than two years, the Black Death claimed nearly half the lives of people in England between 1348 and 1349. Mass graves in England's large Medieval cities have shown how overwhelmed they were. But small rural communities weren't known to have these mass graves until now. . . .
Monasteries also struggled as emergency areas and cemeteries opened in the larger cities. About 11 miles from Thornton, Meux Abbey monks suffered from the Black Death and 80% of them died. This may have left Thornton as one of the only local options.
From CNN.

The underlying cause of this event was probably the Little Ice Age, which left people around the world weakened and vulnerable to a catastrophic disease event. The Medieval Black Death and the earlier Great Famine both hit England and Europe not long after the Little Ice Age climate event, whose start is supported by some key dates:
cold summers and ice growth began abruptly between 1275 and 1300 . . .  
* 1250 for when Atlantic pack ice began to grow; cold period possibly triggered or enhanced by the massive eruption of Samalas volcano in 1257.
* 1275 to 1300 based on the radiocarbon dating of plants killed by glaciation 
* 1300 for when warm summers stopped being dependable in Northern Europe 
* 1315 for the rains and Great Famine of 1315–1317

What was the Great Famine of 1315-1317?

The Great Famine started with bad weather in spring 1315. Crop failures lasted through 1316 until the summer harvest in 1317, and Europe did not fully recover until 1322. The period was marked by extreme levels of crime, disease, mass death, and even cannibalism and infanticide. The crisis had consequences for the Church, state, European society, and for future calamities to follow in the 14th century. . . .  

In the spring of 1316, it continued to rain on a European population deprived of energy and reserves to sustain itself. All segments of society from nobles to peasants were affected but especially the peasants, who represented 95% of the population and who had no reserve food supplies.To provide some measure of relief, the future was mortgaged by slaughtering the draft animals, eating the seed grain, abandoning children to fend for themselves (see "Hansel and Gretel") and, among old people, voluntarily refusing food for the younger generation to survive. The chroniclers of the time noted many incidents of cannibalism, although, self-admittedly, "one can never tell if such talk was not simply a matter of rumor-mongering". 
The height of the famine was in 1317, as the wet weather continued. Finally, in that summer, the weather returned to its normal patterns. By then, however, people were so weakened by diseases such as pneumonia, bronchitis, and tuberculosis, and so much of the seed stock had been eaten, that it was not until 1325 that the food supply returned to relatively normal levels and the population began to increase again. Historians debate the toll, but it is estimated that 10–25% of the population of many cities and towns died. Though the Black Death (1347–1351) would kill more people, it often swept through an area in a matter of months, whereas the Great Famine lingered for years, prolonging the suffering of the populace
The Great Famine was restricted to Northern Europe, including the British Isles, northern France, the Low Countries, Scandinavia, Germany, and western Poland. It also affected some of the Baltic states except for the far eastern Baltic, which was affected only indirectly. The famine was bounded to the south by the Alps and the Pyrenees.

The Little Ice Age, which drove the Great Famine and Black Death events, was in turn most likely, in my opinion, related to volcanic activity: "an especially massive tropical volcanic eruption in 1257, possibly of the now-extinct Mount Samalas near Mount Rinjani, both in Lombok, Indonesia, followed by three smaller eruptions in 1268, 1275, and 1284 did not allow the climate to recover."


DDeden said...

Why do Indonesian volcanoes erupt massively? Tectonic arcs?
Why do they affect north Europe but not Lake Malawi 74ka per 2018 article? Jet stream or predominant ocean currents? Did they cause problems in Australia eg. Wildfires, cooling?

andrew said...

"Why do Indonesian volcanoes erupt massively? Tectonic arcs?"

Off the cuff, I'd suspect it is an offshoot of the collision of the Indian subcontinent plate into Asia, leading to cracks elsewhere. But, yeah, it is definitely a thing, and I'm not sure that we really know why.

"Why do they affect north Europe but not Lake Malawi 74ka per 2018 article? Jet stream or predominant ocean currents?"

Pretty sure it is something like that. I've seen maps reconstructing ash-fall from the Toba eruption and it covers India pretty well but barely dusts the East African coast.

Also, the African continent may be in an ecozone that is more robust, while Northern Europe is on a boundary between arctic and temperate. Shifting that climate boundary a little had a big practical impact. A really bad cold front in Africa is like sweater weather in L.A., in inconvenience but not a lifestyle changing event.

"Did they cause problems in Australia eg. Wildfires, cooling?"

Human arrival in Australia is almost immediately post-Toba, but it is hard to segregate climate impacts v. human occupation impacts. Australia has wildfires that put the current ones to shame at the time of first human occupation which was a major extinction event for megafauna in Australia (a second one came when the dingo was introduced, maybe 8000 years BP). It is widely believed that the human settlers at the time were using this as a hunting tool (either for food or to killed deadly to them predators). But, it could be that climate impacts from Toba made Australia much more vulnerable to this kind of thing than it would have been otherwise at that time.

In my view, a likely cause of that wave of settlement is that Toba was a tipping point event that killed off jungles and the hominins live there adapted to that ecology, creating a window of opportunity for migrating humans that the jungles and their hominin occupants previously made too daunting to challenge and explore.