Abrupt Holocene climate shifts in coastal East Asia, including the 8.2 ka, 4.2 ka, and 2.8 ka BP events, and societal responses on the Korean peninsula

Abstract

Holocene abrupt cooling events have long attracted attention in academia due to public concern that similar rapid changes may reappear in the near future. Thus, considerable progress has been made toward understanding these short-term cooling events in the Northern Hemisphere, particularly in Europe and North America. However, few relevant studies have been conducted in coastal East Asia due to a lack of undisturbed sample materials appropriate for paleoclimate studies. In this study, we examined Holocene abrupt drying events and the Holocene climate optimum (HCO) based on a new high-resolution multi-proxy record (pollen, mean grain size, total organic carbon, carbon/nitrogen ratio) from the south coast of Korea. Possible cultural impacts of the events were also explored using summed probability distributions (SPDs) of archaeological radiocarbon dates. Our arboreal pollen percentage (AP) data clearly indicated drying events centered at 9.8 ka, 9.2 ka, 8.2 ka, 4.7 ka, 4.2 ka, 3.7 ka, 3.2 ka, 2.8 ka, and 2.4 ka BP. The AP data also indicated that forests were severely damaged by a two-step successive drying event during the period from 8.4 ka to 8 ka BP and that the HCO lasted from ca. 7.6 ka to ca. 4.8 ka BP. According to the results of a correlation analysis, climate variations on the Korean peninsula were possibly controlled by shifts in western tropical Pacific (WTP) sea surface temperatures during the past ~5500 years. Simultaneous declines in the SPDs and AP from 2.8 ka to 2.3 ka BP may reflect a demographic reduction attributable to rapid climate deterioration on the peninsula. Refugee agriculturalists might have immigrated to Japan and developed the Yayoi culture. In this study, the 2.8 ka event and its societal impact are recognized clearly for the first time in coastal East Asia.

Disentangling source of moisture driving glacier dynamics and identification of 8.2 ka event: evidence from pore water isotopes, Western Himalaya

“…Consequently, The high percentage of clay throughout the core shows that the porewater stable isotopes have the potential to precisely capture the past climatic events including the 8.2 ka event (Fig. 3).This porewater stable isotopes of clay-rich approach have been also applied by researcher to track the past climatic evenet [27][28][29] Multiple archives and proxies have been used by various researchers to recognize 8.2 ka event, e.g., application of δ 18 O from the Greenland ice core and cave speleothems [32][33][34] arboreal pollen in lake sediments 35 and other multi-proxy records from Himalaya and northwestern India 5,36 .The air masses from Mediterranean, Caspian and Black seas travel a long-distance from the Mediterranean region, leading depleted δ 18 Oporewater and d-excess value above 17‰, during early Holocene, confirming the role of the Westerly precipitation in the Western Himalaya. This is further confirmed by .the presence of Pinus sylvestris pollen from Tso Kar lake in the nearby area also points to the strong influence of the Westerly winds in the region during 8.8-7.4 ka BP 37 .…”

A biodiverse package of southwest Asian grain crops facilitated high-elevation agriculture in the central Tien Shan during the mid-third millennium BCE

“…It is plausible that irrigation technologies spread together with the first farming communities to the central Tien Shan and further eastwards to China [55]. The occupation of Chap II during the second half of the third millennium BCE coincides with the Subboreal climate period of dry and cold conditions [56,57]. People may have been motivated to seek out high-mountain water sources, such as perennial springs, when the lowlands were characterized by water shortages due to glacial melt waters decreasing as precipitation diminished and ice sheets expanded.…”

Changes in Wood Utilization Due to Iron Age Jade Mining in the Western Hexi Corridor: Wood Charcoal Investigations

“…Constraints imposed by the dry environment on the arboreal community identified in our research suggest that the trees used by the JBR miners were not collected locally. To examine the possible source of those trees, understanding the regional vegetation and its historical changes plays a critical role (Pickarski et al, 2015;Schiferl et al, 2017;Xu et al, 2017;Lézine et al, 2019;Park et al, 2019;Zhao et al, 2020). Pollen analysis of natural sediments has recently been used to outline the evolution of vegetation and explore the relationship between human activities and environmental changes in the past (Hou et al, 2015;Huang et al, 2017Huang et al, , 2018Pini et al, 2017;Cheng et al, 2018;Novenko et al, 2018;Qiu et al, 2020).…”