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The association between climate variability and grain harvest yields has been an important component of food security and economy in European history. Yet, inter-regional comparisons of climate–yield relationships have been hampered by locally varying data types and use of different statistical methods. Using a coherent statistical framework, considering the effects of diverse serial correlations on significance, we assess the temperature and hydroclimate (precipitation and drought) signatures in grain harvest yields across varying environmental settings of early modern (c. 1500–1800) Europe. An unprecedentedly large network of yield records from northern (Sweden), central (Switzerland) and southern (Spain) Europe is com- pared with a diverse set of seasonally and annually resolved palaeoclimate reconstructions. Considering the effects of different crop types and time-series frequencies, we find within regions consistent climate–harvest yield patterns characterised by a significant summer soil moisture signal in Sweden, a winter temperature and precipitation signal in Switzerland, and spring and annual mean temperature signals in Spain. The regional scale climate–harvest associations are weaker than the recently revealed signals in early modern grain prices, albeit similar to those observed in modern climate–harvest relationships on comparable spatial scales.

We assess, within a framework of consistent statistical analysis, the inter-annual temperature and hydroclimate signal on grain harvest yields across diverse environmental settings of Europe during the early modern period (c. 1500–1800). To this end, we consider both different grain types and various climate parameters. We go beyond previous studies by applying identical analyses to several regions, by using a larger number of grain yield and harvest records, and by employing a more extensive and diverse set of the latest generation of annually resolved palaeoclimate reconstructions and early instrumental datasets. Hitherto, regional inter-comparisons of historical climate–yield relationships have been constrained by the application of different data and statistical methods. We pay particular attention to the issue of statistical significance in the presence of strong auto-correlation in both the harvest and climate data. Our analyses also consider various seasonal targets, crop types, frequency bands, and lagged harvest responses to climate. Overall, a comparatively weak climate–yield relationship is found, which is consistent with modern observations, as opposed to a strong climate signal we previously have found embedded in early modern grain price data.

Paleoclimate reconstructions have identified a period of exceptional summer and winter cooling in the North Atlantic region following the eruption of the tropical volcano Huaynaputina (Peru) in 1600 CE. A previous study based on numerical climate simulations has indicated a potential mechanism for the persistent cooling in a slowdown of the North Atlantic subpolar gyre (SPG) and consequent ocean–atmosphere feedbacks. To examine whether this mechanism could have been triggered by the Huaynaputina eruption, this study compares the simulations used in the previous study both with and without volcanic forcing and this SPG shift to reconstructions from annual proxies in natural archives and historical written records as well as contemporary historical observations of relevant climate and environmental conditions. These reconstructions and observations demonstrate patterns of cooling and sea-ice expansion consistent with, but not indicative of, an eruption trigger for the proposed SPG slowdown mechanism. The results point to possible improvements in future model–data comparison studies utilizing historical written records. Moreover, we consider historical societal impacts and adaptations associated with the reconstructed climatic and environmental anomalies. This research has been supported by the Swiss National Science Foundation (grant no. P2BEP1_175214), the Swiss National Science Foundation through the SNSF Sinergia CALDERA project (grant no. CRSII5_183571), the Spanish Sci-ence and Innovation Ministry (Ministerio de Ciencia e Innovación) through the STREAM project (grant no. PID2020-114746GBI00), Fonds de la Recherche Scientifique – FNRS and the FWO under the Excellence of Science (EOS) program through the PARAMOUR project (grant no. O0100718F, EOS ID no. 30454083), and the Georgetown Environment Initiative.

The mid-17th century is characterized by a cluster of explosive volcanic eruptions in the 1630s and 1640s, deteriorating climatic conditions culminating in the Maunder Minimum as well as 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, 1641–42 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 December 26, 1640, but sulfate emitted from Koma-ga-take (42° N, Japan) volcano on July 31, 1641, has potentially also contributed to the sulphate 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 sulphate peaks have been confirmed with tephra preserved in ice cores. Tree-ring and written sources point to severe and 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 the late 1630s, and thus preceding the eruptions by some years. The case of the eruption cluster in the late 1630s and early 1640s 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 the impacts of past volcanism must always be studied within the contemporary socio-economic contexts, but that it is also time to most 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 eruptions) to look into their climatic as well as 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 the resulting harvest failures caused by the eruptions. 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 on why and among whom the distal volcanic eruptions resulted in different societal impacts. Such understanding, in turn, can contribute to interdisciplinary research, advice political decision-making, and enhance scientific outreach.

Paleoclimate reconstructions identify a period of exceptional summer and winter cooling in the North Atlantic region following the eruption of the tropical volcano Huaynaputina (Peru) in 1600 CE. Numerical climate simulations indicate a possible eruption-induced mechanism for the persistent cooling in a slowdown of the North Atlantic subpolar gyre (SPG) and consequent ocean-atmosphere feedbacks. To examine the possibility of such an eruption-induced cooling mechanism, this study compares simulations with and without volcanic forcing and an SPG shift to reconstructions from annual proxies in natural archives and historical written records as well as contemporary historical observations of relevant climate and environmental conditions. These reconstructions and observations demonstrate patterns of cooling and sea ice expansion consistent with, but not necessarily indicative of, an eruption trigger for the proposed SPG slowdown mechanism. The results point to possible improvements in future model-data comparison studies utilizing historical written records. Moreover, we consider historical societal impacts and adaptations associated with the reconstructed climatic and environmental anomalies.

A large scholarship currently holds that before the onset of anthropogenic global warming, natural climatic changes long provoked subsistence crises and, occasionally, civilizational collapses among human societies. This scholarship, which we term the ‘history of climate and society’ (HCS), is pursued by researchers from a wide range of disciplines, including archaeologists, economists, geneticists, geographers, historians, linguists and palaeoclimatologists. We argue that, despite the wide interest in HCS, the field suffers from numerous biases, and often does not account for the local effects and spatiotemporal heterogeneity of past climate changes or the challenges of interpreting historical sources. Here we propose an interdisciplinary framework for uncovering climate–society interactions that emphasizes the mechanics by which climate change has influenced human history, and the uncertainties inherent in discerning that influence across different spatiotemporal scales. Although we acknowledge that climate change has sometimes had destructive effects on past societies, the application of our framework to numerous case studies uncovers five pathways by which populations survived—and often thrived—in the face of climatic pressures. Methodological challenges in HCS Challenges in statistical approaches Challenges in qualitative approaches A research framework for HCS Case studies of resilience Exploiting new opportunities Resilient energy systems Resources of trade and empire Political and institutional adaptations Migration and transformation Better histories for better futures

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 assesses the development and current state of climate history research conducted in the five Nordic countries and Estonia. The possible societal impacts of past climatic changes already interested a handful of Nordic historians in the early twentieth century, but the lack of data on past climate fluctuations constrained scholarship in this field until recently. The data availability has increased fundamentally over the past decades due to the advances of palaeoclimatology. However, these advances have created new challenges, related to the ability to utilize data from the natural sciences in historical research as well as acquiring a basic knowledge on climatology. In many European countries, climate history has established itself as a strong academic subfield and consequently has created approaches as to how to overcome some main pitfalls, like climate determinism, related to the early works in the field. These epistemological advances are just beginning to gain a foothold in Nordic historical research. Thus, the article concludes with ten recommendations to improve future research in Nordic climate history.

This article demonstrates how tree-ring material can be applied to historical research using the climate-driven crises of the fourteenth century as a case study. Medieval northeastern Europe is a promising case study for such a purpose, because climate-sensitive tree-ring data are readily available for this period and region. Whereas large areas of western Europe were affected by continuous heavy rains and bitter winters during the 1310s, this dendrochronological evidence suggests that northeastern Europe was not. Favorable climatic conditions prevailed in northeastern Europe in the late 1310s, and, more generally speaking, during the first half of the fourteenth century, as well. The juxtaposition of this new information from tree-ring analyses with the established understanding of the development of the region challenges the view that the crises of the fourteenth century reached the northeasternmost corner of Europe. The case study demonstrates how teleconnections of climate and society, like the crises of the early fourteenth century, can materialize on a societal level very different ways in different locations.

Levanluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence. Extraordinarily broad stable isotopic distribution is observed, indicating three subgroups with distinct dietary habits spanning four centuries. This emphasizes the versatile livelihoods practiced at this boundary of marine, freshwater, and terrestrial ecosystems. While the impact of the prolonged cold darkness of the 6th century was devastating for European communities relying on cultivation, the broad range of livelihoods provided resilience for the Levanluhta people to overcome the abrupt climatic decline.

Climatic factors have affected subsistence strategies throughout human history. In northern Europe and Russia, short-term climatic anomalies and weather extremes are commonly thought to underlie famines in the Middle Ages. However, medieval subsistence crises were not just natural disasters and medieval people were not passive victims of climatic anomalies. In addition, the capacity to cope with climatic anomalies has varied temporally and spatially throughout the Middle Ages. Yet only a few studies have explored the climatic impact on regional medieval food systems comprehensively. This article examines the significance of climate variability on subsistence crises in medieval Novgorod and Ladoga (Russia), focusing on the relationship between short-term climate anomalies and crop cultivation. In addition, this paper evaluates the impact of crop failures, frosts, and other weather phenomena on the food system. The materials are drawn from medieval sources, paleoclimatological reconstructions, and archaeolo...

The European Dendroecologial Fieldweek (EDF) provides an intensive learning experience in tree-ring research that challenges any participant to explore new multidisciplinary dendro-sciences approaches within the context of field and laboratory settings. Here we present the 25th EDF, held in Asturias, NW Spain, in summer 2014. The course, with 33 participants and 10 instructors from 18 countries included advanced training in dendrochronology skills, an overview of tree-ring broad fields and methodological basics to deal with specific research questions as well as applied advanced micro-projects in dendroarchaeology (DAR), dendroclimatology (DCL), dendrogeomorphology (DGM), forest dynamic (FD) and plant anatomy (PA). The results demonstrated the potential of tree-ring research in the Asturias region. The DAR group researched archaeological samples from different contexts (Oviedo cathedral choir stalls, Segovia cathedral roof timbers, Ribadeo shipwreck ship timbers and Bronze Age site charcoal) and explored the supply of wood in different periods. The DCL group established that the Quercus robur and Castanea sativa ring-width measurements show weak climate-growth correlations, where for many trees this is likely caused by management. The strength of the climatic signal could be enhanced using undisturbed settings. The DGM group found that Corylus avellana and Salix spp. are challenging species for dendrogeomorphological studies. Debris-flow events were detected by the presence of tension wood, growth reduction and scars, and their incidences were also supported by local meteorological data. The FD group found that tree growth decreases with increasing competition, a pattern more pronounced in C. sativa than in Pinus sylvestris forest plantations. The results indicate that wood production could be increased by applying thinning treatments on C. sativa. The PA group showed that xylem conduits and phloem area are organized according to the common needs for water supply to leaves and obtain photosynthetic products, regardless site growing conditions for P. sylvestris and Tusilago farfara. In conclusion, this EDF has been a model for interdisciplinary research and international collaboration that has demonstrated that high-quality research and education can be conducted within one week. The EDFs provide an important service to the dendrochronological community and demonstrate the usefulness of this educational-scientific and multi-cultural experience.

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., Kathrin M. Keller, Sandro Blumer, Fortunat Joos and Christoph C. Raible acknowledge support from the Swiss National Science Foundation through project 200020_159563.

Throughout the last millennium, mankind was affected by prolonged deviations from the climate mean state. While periods like the Maunder Minimum in the 17th century have been assessed in greater detail, earlier cold periods such as the 15th century received much less attention due to the sparse information available. Based on new evidence from different sources ranging from proxy archives to model simulations, it is now possible to provide an end-to-end assessment about the climate state during an exceptionally cold period in the 15th century, the role of internal, unforced climate variability and external forcing in shaping these extreme climatic conditions, and the impacts on and responses of the medieval society in Central Europe. Climate reconstructions from a multitude of natural and human archives indicate that, during winter, the period of the early Spörer Minimum (1431–1440 CE) was the coldest decade in Central Europe in the 15th century. The particularly cold winters and normal but wet summers resulted in a strong seasonal cycle that challenged food production and led to increasing food prices, a subsistence crisis, and a famine in parts of Europe. As a consequence, authorities implemented adaptation measures, such as the installation of grain storage capacities, in order to be prepared for future events. The 15th century is characterised by a grand solar minimum and enhanced volcanic activity, which both imply a reduction of seasonality. Climate model simulations show that periods with cold winters and strong seasonality are associated with internal climate variability rather than external forcing. Accordingly, it is hypothesised that the reconstructed extreme climatic conditions during this decade occurred by chance and in relation to the partly chaotic, internal variability within the climate system.

Past agricultural responses to climate variability can helps us to better understand the current and future impacts of climate change on agricultural production. We studied rye (Secale cereale) and barley (Hordeum vulgare) yield responses to temperature fluctuations in Finland during the period 1861–1913. Our analyses demonstrate the high sensitivity of non-industrialised northern agriculture to temperature anomalies. We found evidence of a strong relationship between monthly and seasonal mean temperatures and crop yields. In particular, high spring temperatures were associated with higher yields. Additionally, we tested temperature-sensitive tree-ring series for their value in indicating previous agricultural outputs. The results imply that tree-ring proxies (in particular, maximum latewood density) can provide novel material for studies of historical periods and locations where instrumentally measured climate and harvest data are not available.