Volcanic climate impacts can act as ultimate and proximate causes of Chinese dynastic collapse
Chaochao Gao et al.
Communications Earth & Environment, November 2021
State or societal collapses are often described as featuring rapid reductions in socioeconomic complexity, population loss or displacement, and/or political discontinuity, with climate thought to contribute mainly by disrupting a society’s agroecological base. Here we use a state-of-the-art multi-ice-core reconstruction of explosive volcanism, representing the dominant global external driver of severe short-term climatic change, to reveal a systematic association between eruptions and dynastic collapse across two millennia of Chinese history. We next employ a 1,062-year reconstruction of Chinese warfare as a proxy for political and socioeconomic stress to reveal the dynamic role of volcanic climatic shocks in collapse. We find that smaller shocks may act as the ultimate cause of collapse at times of high pre-existing stress, whereas larger shocks may act with greater independence as proximate causes without substantial observed pre-existing stress. We further show that post-collapse warfare tends to diminish rapidly, such that collapse itself may act as an evolved adaptation tied to the influential “mandate of heaven” concept in which successive dynasties could claim legitimacy as divinely sanctioned mandate holders, facilitating a more rapid restoration of social order.
Did the Colonial mita Cause a Population Collapse? What Current Surnames Reveal in Peru
Miguel Angel Carpio & María Eugenia Guerrer
Journal of Economic History, forthcoming
We present quantitative evidence that the mita introduced by the Spanish crown in 1573 caused the decimation of the native-born male population. The mass baptisms after the conquest of Peru in 1532 resulted in the assignation of surnames for the first time. We argue that past mortality displacement and mass out-migration were responsible for differences in the surnames observed in mita and non-mita districts today. Using a regression discontinuity and data from the Peruvian Electoral Roll of 2011, we find that mita districts have 47 log points fewer surnames than non-mita districts, and fewer surnames exclusive to one location.
Changing social inequality from first farmers to early states in Southeast Asia
Mattia Fochesato et al.
Proceedings of the National Academy of Sciences, 23 November 2021
When the first rice farmers expanded into Southeast Asia from the north about 4,000 y ago, they interacted with hunter-gatherer communities with an ancestry in the region of at least 50 millennia. Rigorously dated prehistoric sites in the upper Mun Valley of Northeast Thailand have revealed a 12-phase sequence beginning with the first farmers followed by the adoption of bronze and then iron metallurgy leading on to the rise of early states. On the basis of the burial rituals involving interment with a wide range of mortuary offerings and associated practices, we identify, by computing the values of the Gini coefficient, at least two periods of intensified social inequality. The first occurred during the initial Bronze Age that, we suggest, reflected restricted elite ownership of exotic valuables within an exchange choke point. The second occurred during the later Iron Age when increased aridity stimulated an agricultural revolution that rapidly led to the first state societies in mainland Southeast Asia.
Triangulation supports agricultural spread of the Transeurasian languages
Martine Robbeets et al.
The origin and early dispersal of speakers of Transeurasian languages — that is, Japanese, Korean, Tungusic, Mongolic and Turkic — is among the most disputed issues of Eurasian population history. A key problem is the relationship between linguistic dispersals, agricultural expansions and population movements. Here we address this question by ‘triangulating’ genetics, archaeology and linguistics in a unified perspective. We report wide-ranging datasets from these disciplines, including a comprehensive Transeurasian agropastoral and basic vocabulary; an archaeological database of 255 Neolithic–Bronze Age sites from Northeast Asia; and a collection of ancient genomes from Korea, the Ryukyu islands and early cereal farmers in Japan, complementing previously published genomes from East Asia. Challenging the traditional ‘pastoralist hypothesis’, we show that the common ancestry and primary dispersals of Transeurasian languages can be traced back to the first farmers moving across Northeast Asia from the Early Neolithic onwards, but that this shared heritage has been masked by extensive cultural interaction since the Bronze Age. As well as marking considerable progress in the three individual disciplines, by combining their converging evidence we show that the early spread of Transeurasian speakers was driven by agriculture.
Process-explicit models reveal pathway to extinction for woolly mammoth using pattern-oriented validation
Damien Fordham et al.
Ecology Letters, forthcoming
Pathways to extinction start long before the death of the last individual. However, causes of early stage population declines and the susceptibility of small residual populations to extirpation are typically studied in isolation. Using validated process-explicit models, we disentangle the ecological mechanisms and threats that were integral in the initial decline and later extinction of the woolly mammoth. We show that reconciling ancient DNA data on woolly mammoth population decline with fossil evidence of location and timing of extinction requires process-explicit models with specific demographic and niche constraints, and a constrained synergy of climatic change and human impacts. Validated models needed humans to hasten climate-driven population declines by many millennia, and to allow woolly mammoths to persist in mainland Arctic refugia until the mid-Holocene. Our results show that the role of humans in the extinction dynamics of woolly mammoth began well before the Holocene, exerting lasting effects on the spatial pattern and timing of its range-wide extinction.