Synchronised Greenland and Antarctic ice-core sulphate records show a cluster of four major bipolar volcanic eruptions in the roughly 110 years immediately before the Younger Dryas onset, with a cumulative Northern Hemisphere radiative forcing exceeding that of the most volcanically active periods of the Common Era.

Synchronized Greenland and Antarctic ice-core sulphate records document a cluster of four major bipolar volcanic eruptions between 12,980 and 12,870 yr BP, immediately preceding the Younger Dryas onset. Reconstructed radiative forcing indicates an aerosol burden exceeding that of any comparable interval in the Common Era, establishing a documented terrestrial forcing mechanism. The strongest opposing consideration is that temporal proximity alone does not prove that these eruptions were climatically sufficient to trigger prolonged ocean circulation collapse.

Abbott et al. 2021 document, in synchronized Greenland and Antarctic sulphate records, a ~110-year cluster of four major bipolar eruptions immediately before the Younger Dryas onset, with cumulative Northern Hemisphere forcing exceeding the most volcanically active Common Era periods. The strongest opposing consideration is that this is one reconstruction documenting a forcing, not a demonstrated cause — comparable eruptions occur elsewhere in the glacial record, and the paper itself calls for the model experiments that would test causation.

YDIH-E041 reports synchronized Greenland and Antarctic sulphate evidence for four major bipolar eruptions within roughly 110 years before Younger Dryas inception and reconstructs a cumulative Northern Hemisphere forcing exceeding the most active Common Era intervals. This is strong evidence for the stated eruption cluster and modeled forcing comparison, but it does not show that the eruptions caused the Younger Dryas. The strongest opposing consideration is that the result rests on one reconstruction and that comparably large eruptions occur elsewhere without an equivalent climatic transition.

Synchronized Greenland–Antarctic sulphate records document a ~110-year cluster of four major bipolar volcanic signals immediately before Younger Dryas inception whose cumulative Northern Hemisphere radiative forcing exceeds the most active Common Era intervals. Strongest opposing consideration is that comparable eruptions occur elsewhere in the glacial record and model experiments confirming tipping-point efficacy are still needed.

Abbott et al. 2021 use synchronised Greenland and Antarctic sulphate records to document a ~110-year cluster of four major bipolar volcanic signals between about 12,980 and 12,870 a BP (E041). They estimate cumulative Northern Hemisphere forcing exceeding the most volcanically active Common Era periods. Svensson et al.'s use of a volcanic quadruplet of large acidity spikes to synchronise the onset between hemispheres independently corroborates the cluster's existence (E038). The forcing comparison rests on one reconstruction and on converting deposited sulphate into forcing for eruptions whose sources, and hence latitudes and injection heights, are unidentified. Strongest opposing consideration: eruptions of this individual size recur in the glacial record (16th and 17th of 1,113 by sulphur in the catalogue Green et al. cite), so the cluster's existence is firmer than its exceptionality; the claim asserts no causation, and its bearing on C020 is as a correctly timed rival forcing, not a refutation.

A continuous reconstruction from synchronised Greenland and Antarctic sulphate records, published in Quaternary Science Reviews and consistent with the 2020 bipolar synchronisation, which used the same four acidity spikes to tie the two hemispheres' records at the onset. The eruptions are measured; their sources are unidentified and their climatic effect is estimated, not observed.