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As prominent abrupt climatic events during the last deglaciation and the early Holocene, the Younger Dryas (YD) and the 8.2 ka events have been intensely discussed to reveal the relationship between their phases and intensities, and their underlying mechanisms based on massive marine and terrestrial archives. However, the related paleoclimate records with sufficient resolution and/or precise age constraints from the Southern Hemisphere, especially East Africa, are relatively sparse, hindering our comprehensive understanding about the phases of these two events. Here, we provide a precisely dated record of an aragonite-calcite stalagmite covering 11.3–13.5 ka BP from northwest Madagascar to unravel the arid conditions during the YD, in contrast to the pluvial conditions in the 8.2 ka event that has been evidenced before. Changes in austral summer precipitation related to the Intertropical Convergence Zone (ITCZ) have always been interpreted to be the primary means of controlling regional rainfall amounts and thus the δ18O variations in stalagmite. However, ITCZ's meridional migration alone is not enough to interpret the opposite hydroclimatic conditions during the YD and the 8.2 ka events in northwest Madagascar. The variation in convection intensity within the ITCZ combined with the rainfall dipole mode in East Africa, and the redistribution of the duration of the ITCZ's presence at different latitudes might be responsible for this phenomenon. In addition, sea surface temperature could play a nonnegligible role. [ABSTRACT FROM AUTHOR]

The Asian monsoon (AM) has direct and profound effects on the livelihoods of residents in South Asia and East Asia. Modern observations have shown multi-decadal alternations of flood and drought periods in these regions, likely influenced by climatic processes such as the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation. However, our understanding of the multi-decadal variability of the AM under different climatic conditions remains uncertain. In this study, we collected an annually laminated and 780-mm stalagmite (sample number: BJ7) from Binjia (BJ) Cave in southwestern China, which is deeply influenced by the Asian monsoon system. Based on this sample, we established 6-year resolution and multi-proxy records for the Asian summer monsoon (ASM) variabilities during the early last termination, spanning from 18.2 to 16.1 ka BP. Measurements of five pairs of uranium and thorium solutions for 230Th dating were conducted using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP- MS), and 374 pairs of stable isotope (δ18O and δ13C) analyses were run on a Kiel Carbonate Device connected with Finnigan MAT-253 at Nanjing Normal University. The chronology for this sample was established by annual layer counting anchored with 230Th dating results. Our BJ7 δ18O record replicates well with other Chinese δ18O records on the general trend, all of which are superimposed by frequent multidecadal-scale fluctuations at approximately 60 years periodicity. Inspection of the 60-year band in BJ7 δ18O and δ13C records and results of the cross-wavelet analysis indicate coherent changes in the ASM and biomass production/karst processes during most of the studied period. In addition, the 60-year band of BJ7 and NGRIP δ18O records are consistent, implying the impacts of the high-latitude North Atlantic or Atlantic Multidecadal Oscillation on the ASM. Our study suggests that the 60-year variability should be an intrinsic feature of the climate system regardless of glacial or interglacial backgrounds. [ABSTRACT FROM AUTHOR]