The Hunnic incursions into eastern and central Europe in the 4th and 5th c. CE have historically been considered one of the key factors in bringing the Roman Empire to an end. However, both the origins of the Huns and their impact on the late Roman provinces remain poorly understood. Here we provide a new, combined assessment of the archaeological, historical, and environmental evidence. Hunnic raids and warfare within the Roman provinces are most intensely attested for the first half of the 5th c. We propose that severe drought spells in the 430s to 450s CE disrupted the economic organization of the incomers and local provincial populations, requiring both to adopt strategies to buffer against economic challenges. We argue that the Huns’ apparently inexplicable violence may have been one strategy for coping with climatic extremes within a wider context of the social and economic changes that occurred at the time.

Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.

As the worldwide standard for radiocarbon (14C) dating over the past ca. 50,000 years, the International Calibration Curve (IntCal) is continuously improving towards higher resolution and replication. Tree-ring-based 14C measurements provide absolute dating throughout most of the Holocene, although high-precision data are limited for the Younger Dryas interval and farther back in time. Here, we describe the dendrochronological characteristics of 1448 new 14C dates, between ~11,950 and 13,160 cal BP, from 13 pines that were growing in Switzerland. Significantly enhancing the ongoing IntCal update (IntCal20), this Late Glacial (LG) compilation contains more annually precise 14C dates than any other contribution during any other period of time. Thus, our results now provide unique geochronological dating into the Younger Dryas, a pivotal period of climate and environmental change at the transition from LG into Early Holocene conditions.

Advances in accelerator mass spectrometry have resulted in an unprecedented amount of new high-precision radiocarbon (14C) -dates, some of which will redefine the international 14C calibration curves (IntCal and SHCal). Often these datasets are unaccompanied by detailed quality insurances in place at the laboratory, questioning whether the 14C structure is real, a result of a laboratory variation or measurement-scatter. A handful of intercomparison studies attempt to elucidate laboratory offsets but may fail to identify measurement-scatter and are often financially constrained. Here we introduce a protocol, called Quality Dating, implemented at ETH-Zürich to ensure reproducible and accurate high-precision 14C-dates. The protocol highlights the importance of the continuous measurements and evaluation of blanks, standards, references and replicates. This protocol is tested on an absolutely dated German Late Glacial tree-ring chronology, part of which is intercompared with the Curt Engelhorn-Center for Archaeometry, Mannheim, Germany (CEZA). The combined dataset contains 170 highly resolved, highly precise 14C-dates that supplement three decadal dates spanning 280 cal. years in IntCal, and provides detailed 14C structure for this interval.

The Last Glacial–Interglacial Transition (LGIT; 15,000–11,000 cal BP) was characterized by complex spatiotemporal patterns of climate change, with numerous studies requiring accurate chronological control to decipher leads from lags in global paleoclimatic, paleoenvironmental, and archaeological records. However, close scrutiny of the few available tree-ring chronologies and radiocarbon-dated sequences composing the IntCal13 14C calibration curve indicates significant weakness in 14C calibration across key periods of the LGIT. Here, we present a decadally resolved atmospheric 14C record derived from New Zealand kauri spanning the Lateglacial from ~13,100–11,365 cal BP. Two floating kauri 14C time series, curve-matched to IntCal13, serve as a 14C backbone through the Younger Dryas. The floating Northern Hemisphere (NH) 14C data sets derived from the YD-B and Central European Lateglacial Master tree-ring series are matched against the new kauri data, forming a robust NH 14C time series to ~14,200 cal BP. Our results show that IntCal13 is questionable from ~12,200–11,900 cal BP and the ~10,400 BP 14C plateau is approximately 5 decades too short. The new kauri record and repositioned NH pine 14C series offer a refinement of the international 14C calibration curves IntCal13 and SHCal13, providing increased confidence in the correlation of global paleorecords.

Radiocarbon measurements in tree rings can be used to estimate atmospheric 14C concentration and thereby used to create a 14C calibration curve. When wood is discovered in construction sites, rivers, buildings, and lake sediments, it is unclear if the wood could fill gaps in the 14C calibration curve or if the wood is of historical interest until the age is determined by dendrochronology or 14C dating. However, dendrochronological dating is subjected to many requirements and 14C dating is costly and time consuming, both of which can be frivolous endeavors if the samples are not in the age range of interest. A simplified 14C dating technique, called Speed Dating, was thus developed. It can be used to quickly obtain 14C ages as wood samples are neither chemically treated nor graphitized. Instead, wood is combusted in an elemental analyzer (EA) and the CO2 produced is carried into an accelerator mass spectrometer (AMS) with a gas ion source. Within a day, 75 samples can be measured with uncertainties between 0.5–2% depending on the age, preservation, and contaminants on the material and Speed Dating costs about one-third of conventional AMS dates.