This article evaluates 165 studies from various disciplines, published between 2000 and 2019, which in different ways link past climate variability and change to human history in medieval and early modern Europe (here,c. 700–1815 CE). Within this review, we focus on the identification and interpretation of causal links between changes in climate and in human societies. A revised climate–society impact order model of historical climate–society interactions is presented and applied to structure the findings of the past 20 years' scholarship. Despite considerable progress in research about past climate–society relations, partly expedited by new palaeoclimate data, we identify limitations to knowledge, including geographical biases, a disproportional attention to extremely cold periods, and a focus on crises. Furthermore, recent scholarship shows that the limitations with particular disciplinary approaches can be successfully overcome through interdisciplinary collaborations. We conclude the article by proposing recommendations for future directions of research in the climatic change–human history nexus.This article is categorized under: Climate, History, Society, Culture > Ideas and Knowledge

Changes in climate affected human societies throughout the last millennium. While European cold periods in the 17th and 18th century have been assessed in detail, earlier cold periods received much less attention due to sparse information available. New evidence from proxy archives, historical documentary sources and climate model simulations permit us to provide an interdisciplinary, systematic assessment of an exceptionally cold period in the 15th century. Our assessment includes the role of internal, unforced climate variability and external forcing in shaping extreme climatic conditions and the impacts on and responses of the medieval society in north-western and central Europe.Climate reconstructions from a multitude of natural and anthropogenic archives indicate that the 1430s were the coldest decade in north-western and central Europe in the 15th century. This decade is characterised by cold winters and average to warm summers resulting in a strong seasonal cycle in temperature. Results from comprehensive climate models indicate consistently that these conditions occurred by chance due to the partly chaotic internal variability within the climate system. External forcing like volcanic eruptions tends to reduce simulated temperature seasonality and cannot explain the reconstructions. The strong seasonal cycle in temperature reduced food production and led to increasing food prices, a subsistence crisis and a famine in parts of Europe. Societies were not prepared to cope with failing markets and interrupted trade routes. In response to the crisis, authorities implemented numerous measures of supply policy and adaptation such as the installation of grain storage capacities to be prepared for future food production shortfalls.

Historical climatology is an interdisciplinary field of research encompassing the reconstruction of past climate and weather from written sources and artifacts, as well the application of climate reconstructions to the study of human history. Historical climatology has grown in recent years, and this growth has brought both insights and challenges. Research has expanded into new regions and periods and diversified into novel sources, methods, and interdisciplinary collaborations. At the same time, the heterogeneity of evidence and approaches has complicated the integration of multiple climate and weather reconstructions. Moreover, the diversity of disciplinary perspectives, terminologies, and perspectives can create miscommunication among scholars in the field, particularly on issues of historical knowledge and causation. Innovative approaches in the field, including Bayesian methods, may help address these challenges.This article is categorized under: Climate, History, Society, Culture > Disciplinary Perspectives Climate, History, Society, Culture > World Historical Perspectives Assessing Impacts of Climate Change > Representing Uncertainty The Social Status of Climate Change Knowledge > Knowledge and Practice

The mid-17th century is characterized by a cluster of explosive volcanic eruptions in the 1630s and 1640s, climatic conditions culminating in the Maunder Minimum, and political instability and famine in regions of western and northern Europe as well as China and Japan. This contribution investigates the sources of the eruptions of the 1630s and 1640s and their possible impact on contemporary climate using ice core, tree-ring, and historical evidence but will also look into the socio-political context in which they occurred and the human responses they may have triggered. Three distinct sulfur peaks are found in the Greenland ice core record in 1637, 1641–1642, and 1646. In Antarctica, only one unambiguous sulfate spike is recorded, peaking in 1642. The resulting bipolar sulfur peak in 1641–1642 can likely be ascribed to the eruption of Mount Parker (6^∘ N, Philippines) on 26 December 1640, but sulfate emitted from Komaga-take (42^∘ N, Japan) volcano on 31 July 1641 has potentially also contributed to the sulfate concentrations observed in Greenland at this time. The smaller peaks in 1637 and 1646 can be potentially attributed to the eruptions of Hekla (63^∘ N, Iceland) and Shiveluch (56^∘ N, Russia), respectively. To date, however, none of the candidate volcanoes for the mid-17th century sulfate peaks have been confirmed with tephra preserved in ice cores. Tree-ring and written sources point to cold conditions in the late 1630s and early 1640s in various parts of Europe and to poor harvests. Yet the early 17th century was also characterized by widespread warfare across Europe – and in particular the Thirty Years' War (1618–1648) – rendering any attribution of socio-economic crisis to volcanism challenging. In China and Japan, historical sources point to extreme droughts and famines starting in 1638 (China) and 1640 (Japan), thereby preceding the eruptions of Komaga-take (31 July 1640) and Mount Parker (4 January 1641). The case of the eruption cluster between 1637 and 1646 and the climatic and societal conditions recorded in its aftermath thus offer a textbook example of difficulties in (i) unambiguously distinguishing volcanically induced cooling, wetting, or drying from natural climate variability and (ii) attributing political instability, harvest failure, and famines solely to volcanic climatic impacts. This example shows that while the impacts of past volcanism must always be studied within the contemporary socio-economic contexts, it is also time to move past reductive framings and sometimes reactionary oppositional stances in which climate (and environment more broadly) either is or is not deemed an important contributor to major historical events.

Past volcanic eruptions and their climatic impacts have been linked increasingly with co-occurring societal crises – like crop failures and famines – in recent research. Yet, as many of the volcanic cooling studies have a supra-regional or hemispheric focus, establishing pathways from climatic effects of an eruption to human repercussions has remained very challenging due to high spatial variability of socio-environmental systems. This, in turn, may render a distinction of coincidence from causation difficult. In this study, we employ micro-regionally resolved natural and written sources to study three 17th century volcanic eruptions (i.e., 1600 Huaynaputina, 1640/1641 Koma-ga-take–Parker, and 1695 unidentified) to look into their climatic and socioeconomic impacts among rural agricultural society in Ostrobothnia (Finland) with high temporal and spatial precision. Tree-ring and grain tithe data indicate that all three eruptions would have caused significant summer season temperature cooling and poor grain harvest in the region. Yet, tax debt records reveal that the socioeconomic consequences varied considerably among the eruptions as well as in time, space, and within the society. Whether the volcanic events had a strong or weak socioeconomic effect depended on various factors, such as the prevailing agro-ecosystem, resource availability, material capital, physical and immaterial networks, and institutional practices. These factors influenced societal vulnerability and resilience to cold pulses and associated harvest failures. This paper proposes that, besides detecting coinciding human calamities, more careful investigation at the micro-regional scale has a clear added value as it can provide deeper understanding of why and among whom the distal volcanic eruptions resulted in different societal impacts. Such understanding, in turn, can contribute to interdisciplinary research, advise political decision-making, and enhance scientific outreach.