Holocene climate, fire, and human impact in southern Korea inferred from pollen and charcoal records

Understanding Holocene climate variability and vegetation changes driven by human activities provides essential insights into future climate and ecosystem changes. In this study, we obtained high-resolution (average of 40 years) pollen and sedimentary charcoal records from paleo-lake Gaho in South Korea over the past 7000 years. Based on the modern pollen assemblage dataset, we quantitatively reconstructed the annual mean temperature (T ann ) and annual precipitation (P ann ) using the weighted-modern analogue technique (wMAT). The reconstructed T ann value (9.1–12.3 °C) was closely related to Bond events and fluctuation in the East Asian winter monsoon (EAWM). The reconstructed P ann value (1250–1540 mm) showed a trend consistent with records of Intertropical Convergence Zone (ITCZ) swing and East Asian summer monsoon (EASM) intensity. These hydroclimatic variations are consistent with the Gaho lake water level, geochemical proxies, and principal component analysis (PCA). Our charcoal records revealed persistent fire activity in this region, with a pronounced increase in strong fires that occurred at approximately 5000–4000 cal yr BP probably due to progressive drying and increased biomass fuel availability. After 3400 cal yr BP, increases in large Poaceae pollen grains (>40 μm) indicated traces of agricultural activity, while human influence intensified after 2000 cal yr BP; these agree with abrupt fluctuations in Pinus and Quercus . Therefore, fire occurrences after 2000 cal yr BP are likely predominantly anthropogenic and related to warfare, metallurgy, and land-use practices. These findings enhance our understanding of the coupled effects of climate change and human impacts on Holocene vegetation in the Korean Peninsula and provide a basis for anticipating and managing future responses to ongoing climate change. • The reconstructed T ann ranges from 9.1 to 12.3 °C and is closely linked to Bond events and EAWM. • The reconstructed P ann ranges from 1250 to 1540 mm and shows a strong correspondence with records of ITCZ swing and the EASM. • Human activity began ca. 3400 cal yr BP, with charcoal indicating natural fires before this period and human impact afterward.