Exploring the environmental and cultural consequences of the 8.2 ka cooling event in Kyushu, Southwestern Japan

Abstract

Japan’s rich archaeological record, supported by well-established chronological and typological frameworks, offers valuable opportunities to investigate prehistoric socio-cultural responses to climate change, although comprehensive studies remain limited. This exploratory paper examines the impact of climatic disruptions—particularly the 8.2 ka event—on Jomon foragers in Kyushu, aiming to develop an analytical framework and identify future research directions. The 8.2 ka event is situated within a longer socio-ecological trajectory extending from the onset of the Holocene (11.7 ka) to the Kikai-Akahoya (K-Ah) super-eruption (7.3 ka). Early Holocene Kyushu is typically characterised by the emergence of large, village-based foraging communities, whose abrupt decline has been attributed to the K-Ah eruption, often considered a cultural and demographic watershed. However, this study reconsiders that narrative by comparing environmental changes with archaeological trends in population, settlement, and subsistence. Methods include (a) reviewing environmental history literature; (b) assessing demographic patterns through settlement data and technological trends; and (c) analysing lithic tools and faunal remains at key sites. Our findings suggest a more complex sequence structured by three tempos of environmental change: (1) the gradual postglacial northward move of nut-bearing deciduous forests; (2) short-term climatic downturns, including the 8.2 ka event and other Bond Events; and (3) abrupt volcanic impacts. Each phase appears to have triggered cumulative and adaptive socio-cultural responses. We tentatively conclude that the 8.2 ka event impacted communities already undergoing long-term adaptation to dynamic and unstable ecological conditions, shaped by both environmental constraints and opportunities. These groups responded in cyclical ways to different tempos of change. Ultimately, we argue that the 8.2 ka event in Kyushu should be examined as part of a broader trajectory of socio-ecological transformation, rather than as an isolated moment of major disruption.