Volcanic eruptions caused weakening AMOC during the preindustrial past millennium.

Chen, Kefan; Liu, Zhengyu; Ning, Liang; Liu, Jian; Lei, Lili; Mann, Michael E; Yan, Mi; Sun, Weiyi et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of our climate system. However, the evolution history and the forcing mechanism of AMOC in the last millennial has remained uncertain. Here, combining available paleo AMOC-sensitive indicators with multiple climate models and paleo Data Assimilation, we show, for the first time, that the AMOC transport exhibits a slow declining trend into the Little Ice Age, with a reduction of about <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>-</mo><mn>0.7</mn><mspace></mspace><mo>±</mo><mn>0.4</mn><mi>S</mi><mi>v</mi><mo>.</mo></math> (~4%) from AD 850-1850. This weakening is mainly caused by explosive volcanic eruptions. After a rapid strengthening in the initial decade following a volcanic eruption, the AMOC tends to show a slow weakening of centennial timescale, driven by stored cooling in the deep Atlantic and its feedback on North Atlantic climate.