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The Millennium Eruption (AD 946–947) of Changbaishan Tianchi Volcano is one of the largest known eruptions in recorded history. With the help of previously published isopachs and distal ash thicknesses, we re-calculate the bulk volume of its distal eruptive product, the B-Tm ash, as 27–62 km3 and the total eruption volume as 40–98 km3. The updated volume estimates are around half of those estimated by previous studies of this seminal eruption. Our work shows that the Millennium Eruption is a VEI-6 eruption, rather than VEI-7 as previously envisaged, and its magnitude is also lower than previously thought. This has implications for regional frequency-magnitude relationships and may also partially explain the limited regional, rather than global, climatic effects of the Millennium Eruption.

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High-resolution analyses of pollen and diatoms in core LV 53-29 from the northwestern Japan Sea trace climate, vegetation and oceanographic changes during the past 120 ka. The age model for the core was based on tephrochronology, colour lightness and magnetic susceptibility and was used to aid correlation with Dansgaard-Oeschger cycles (warm Greenland interstadials (GIs) and cold Greenland stadials (GSs)). The palynological and diatom data from this core record the changing influences of the East Asian monsoon, eustatic fluctuations in sea level, and the impact of variations in the direction and intensity of marine currents. Increases in Quercus and Cryptomeria pollen reflect GIs. The highest values of Cryptomeria were recorded during Marine Isotope Stage (MIS) 5 and were associatedwith an increase in the intensityof the summer monsoon. The increase in Larix pollen is an indicatorof GSs, and it occurs in all marine isotopic stages. Changes in diatom records indicate that oceanographic conditions in the northwestern Japan Sea differed from its southern and eastern regions. An increase in the cold-water and polyhalobous Rhizosolenia hebetata indicates GIs, although the surface water temperatures were colder than today with normal salinity. Species of the genus Chaetoceros, which is characteristic of GSs, were abundant during MIS 2. The predominance of Chaetoceros taxa and the high total abundance of diatoms may reflect regional upwelling conditions. The absence of brackish-water species at this time indicates a slight freshening of the surface water. The study of pollen, spores and diatoms in sediments from the northwestern Japan Sea illustrates the great potential of these proxies for identifying abrupt climate oscillations preserved in high-temporal resolution marine records, particularly those related to interstadial and stadial conditions.