Вадим Дудченко
Администратор портала

One or more volcanic eruptions preceded the majority (62 of 68) of dynastic collapses in China over the past 2,000 years, according to new research led by Zhejiang University and Trinity College Dublin scientists.

Tang Dynasty mural commemorating the victory of General Zhang Yichao over the Tibetans in 848 CE, from Mogao cave 156.

“China’s long history thus presents an unrivaled opportunity to examine whether abrupt climatic change has a role in the recurrent and precisely datable collapse of 68 dynasties throughout the first two millennia CE,” said first author Dr. Chaochao Gao of Zhejiang University and colleagues.

“The fall of these dynasties is often described in terms of ‘collapse’.”

“Some certainly occurred with apparent rapidity in the context of intense conflict and with the significant agroecological and socioeconomic disruption and population loss that are important components in many cases and definitions of collapse, but others occurred as less-disruptive transitions between ruling families and elites, with considerable bureaucratic and economic continuities.”

“These events have also been historically set in the context of a ‘dynastic cycle,’ in which dynasties proceeded through a period of virtue and vigor before decline and collapse, often traditionally credited to the immorality and corruption of the ruling family and elites.”

“Socioeconomic and demographic pressures, mass migrations, and population displacements, alongside mismanagement of natural resources and environmental degradation, are now more often stressed as causal factors.”

“The contribution of climatic stresses has also begun to assume increased — though often controversial — prominence, for example with the collapse of the Tang Dynasty in 907 CE, the Yuan Dynasty in 1368 CE, and the Ming Dynasty in 1644 CE linked to episodes of drought and cold.”

“Explosive volcanism has also been proposed as an underlying climatic forcing associated with specific individual collapses, but the extent to which such observations are generalizable to the broader multi-millennium history of dynastic collapse, with explosive volcanism — and abrupt climatic change by extension — playing a systematic role, has never been established.”

Chinese dynastic collapse, explosive volcanism, and warfare frequency, 1-1911 CE: consensus dates for 68 dynastic collapses (blue dashed vertical columns), overlain by ice-core-based dates and climate forcing potential of inferred-tropical and extratropical northern hemispheric explosive volcanic eruptions (n=156) as inferred by multi-ice-core measurements of polar sulfate deposition (graduated red circles), for 1-1911 CE. Also shown is annual warfare frequency from 850 to 1911 CE (continuous tan line), with the thick brown line representing a 10-year smoothing using the Savitzky-Golay filter. The figure is split into two consecutive periods for visual clarity; a and b cover the first and second millennia CE, respectively. Image credit: Gao et al., doi: 10.1038/s43247-021-00284-7.

In their study, the scientists reconstructed 156 explosive volcanic eruptions from 1 CE to 1915 by examining elevated sulfate levels in ice cores from Greenland and Antarctic.

They also analyzed historical documents from China on 68 dynasties and examined warfare there between 850 and 1911.

They found that smaller volcanic ‘shocks’ to the climate may cause dynasties to collapse when political and socioeconomic stress is already high.

Larger shocks may lead to collapses without substantial pre-existing stress.

Other factors include poor leadership, administrative corruption and demographic pressures.

“With so many precisely dated collapses, we can look not just at individual cases of collapse that may or may not have followed a change in climate, but rather look simultaneously at many collapses to see whether there is a repeated pattern where a change in climate was followed by collapse,” said co-lead author Dr. Francis Ludlow, a researcher at Trinity College Dublin.

“This can tell us whether climatic change played a very minor role in dynastic collapse, or whether it posed a systematic threat to these powerful and sophisticated societies.”

The authors found that 62 of the 68 dynastic collapses in China were closely preceded by at least one volcanic eruption.

“We found that even a small volcanic eruption might help trigger a collapse when pre-existing instability was high,” said co-author Dr. John Matthews, a postdoctoral researcher at Trinity College Dublin.

“Larger eruptions, however, could trigger a collapse even when pre-existing instability was minimal.”

“So as ever, historical context is key to understanding how climate can impact a society.”

“It is also clear that we should be preparing for the impacts of the next big eruption — so far in the twentieth and twenty-first centuries, the eruptions we’ve experienced have been minnows compared to some that these dynasties had to deal with.”

The study appears in the journal Communications Earth & Environment.

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C. Gao et al. 2021. Volcanic climate impacts can act as ultimate and proximate causes of Chinese dynastic collapse. Commun Earth Environ 2, 234; doi: 10.1038/s43247-021-00284-7

 



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