On the brink of Armageddon? Climate change, the archaeological record and human activity across the Bronze Age–Iron Age transition in Ireland

Abstract

Palaeoclimatic proxies from records in northwest Europe evidence a climatic deterioration, known as the ‘2.8 ka Event’, which broadly coincided with the transition from Later Bronze Age to Iron Age in Ireland. This Bronze Age-Iron Age transition in Ireland has been invoked in various hypotheses concerning the relationship between environmental and cultural change. This paper offers a brief review of contrasting archaeological interpretations of the transition, outlines the gaps and uncertainties in current knowledge and highlights the role of climate change in some of these uncertainties. This is followed by a discussion of palaeoclimate records from peatlands, and in particular the utility of bog surface wetness records (BSW) to identify geographically and chronologically coherent periods of Holocene climate change, including the period around 750 BC (2.8 ka), which is apparent in both UK and Irish records. Whilst BSW records provide evidence of relative shifts from wet/cold to warm/dry conditions, quantitative indices of temperature and precipitation cannot be derived from these data. Recent work discounting a link between a demographic ‘collapse’ and climate change is considered, as is the importance of local-scale records for understanding the archaeology of peatlands. The role of ‘bog burst’ events (catastrophic hydrological failures of the physical integrity of peatland) in driving palaeohydrological changes in certain Irish peatlands is outlined. Whilst ‘bog bursts’ might confound the extraction of regional climatic meaning, they provide important contextual evidence for human activity and the associated archaeological record. Although there are some coherent patterns in palynological records, others demonstrate spatial and chronological differences in vegetation change and human impact across the Late Bronze Age to Iron Age, but the implications for changes in the distribution of human populations are unclear. The paper concludes with a consideration of the importance of robust chronologies for integrating archaeological, palaeoenvironmental and palaeoclimatological data to investigate potential links between climate and cultural change. The importance of different analytical, spatial and chronological scales to investigate the complex and recursive nature of the relationship between human activity and climatic change is discussed.