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Abstract Existing global volcanic radiative aerosol forcing estimates portray the period 700 to 1000 as volcanically quiescent, void of major volcanic eruptions. However, this disagrees with proximal Icelandic geological records and regional Greenland ice-core records of sulfate. Here, we use cryptotephra analyses, high-resolution sulfur isotope analyses, and glaciochemical volcanic tracers on an array of Greenland ice cores to characterise volcanic activity and climatically important sulfuric aerosols across the period 700 to 1000. We identify a prolonged episode of volcanic sulfur dioxide emissions (751–940) dominated by Icelandic volcanism, that we term the Icelandic Active Period. This period commences with the Hrafnkatla episode (751–763), which coincided with strong winter cooling anomalies across Europe. This study reveals an important contribution of prolonged volcanic sulfate emissions to the pre-industrial atmospheric aerosol burden, currently not considered in existing forcing estimates, and highlights the need for further research to disentangle their associated climate feedbacks. 

Persistent droughts in Arabia were coincident with profound societal changes there during the 6th century CE. 

Abstract With the efflorescence of palaeoscientific approaches to the past, historians have been confronted with a wealth of new evidence on both human and natural phenomena, from human disease and migration through to landscape change and climate. These new data require a rewriting of our narratives of the past, questioning what constitutes an authoritative historical source and who is entitled to recount history to contemporary societies. Humanities-based historical inquiry must embrace this new evidence, but to do so historians need to engage with it in a critical manner, just as they engage critically with textual and material sources. This article highlights the most vital methodological issues, ranging from the spatiotemporal scales and heterogeneity of the new evidence to the new roles attributed to quantitative methods and the place of scientific data in narrative construction. It considers areas of study where the palaeosciences have “intruded” into fields and subjects previously reserved for historians, especially socioeconomic, climate, and environmental history. The authors argue that active engagement with new approaches is urgently needed if historians want to contribute to our evolving understanding of the challenges of the Anthropocene.