Climate Impacts of the Millennium Eruption of Changbaishan Volcano.

The Millennium Eruption of Changbaishan Volcano is heralded as one of the largest explosive eruptions in the Late Holocene and produced huge quantities of tephra. The petrogeochemical method estimates that the Millennium Eruption emitted up to 45 Tg of sulfur into the atmosphere—more than in the Tambora eruption in 1815 CE, which caused "a year without a summer" across the Northern Hemisphere in 1816 CE. Despite such massive emissions, evidence for this eruption's climate impact in East Asia remains elusive. To explain this contradiction, this study used 67 high‐resolution tree‐ring‐width records from the Northern Hemisphere spanning the past two millennia, complemented by volcanic sensitivity experiments conducted with the Community Earth System Model. Results reveal a prevailing decreasing/negative trend in the proxy records during the potential eruption period, with 945 CE marking the most notable negative anomaly, suggesting that the Millennium Eruption likely occurred in 945 CE rather than 946 CE. Sensitivity experiments, corroborated by proxy records, demonstrate that the Millennium Eruption induced substantial negative temperature anomalies at middle and high latitudes, alongside an increase in Meiyu‐Baiu‐Changma precipitation in the middle and lower reaches of the Yangtze River and southwestern Japan and a decrease in precipitation in India, northern China, and the South China Sea in the first post‐eruption year. This study offers a novel perspective on the climate impact of the Millennium Eruption, reconciling previous discrepancies regarding its climate impact. Plain Language Summary: About a thousand years ago, the Changbaishan volcano erupted with incredible force, ranking as one of the largest historical eruptions in the past 2000 yrs. Despite its size, evidence for this eruption's climate impact in East Asia has remained elusive. We delved into this mystery by examining detailed high‐resolution proxy records and performing climate model simulations. Our findings suggest that the climate effects of the eruption may have been unexpectedly strong, with the Millennium Eruption potentially occurring in 945 CE that is earlier than previously thought. The Millennium Eruption triggered notable cooling at middle and high latitudes, increased Meiyu‐Baiu‐Changma precipitation in the middle and lower reaches of the Yangtze River and southwestern Japan, and reduced precipitation in India, northern China, and the South China Sea. This research helps us understand how large volcanic eruptions can interact with other natural factors to influence our climate. Key Points: Sulfur emissions of the Millennium Eruption estimated from a petrogeochemical method are inconsistent with the signal from ice‐core samplesA consistent negative response in the high‐resolution paleoclimate records suggests a significant climate impact of the Millennium EruptionThe eruption enhanced the Meiyu‐Baiu‐Changma precipitation while diminishing precipitation in India, northern China, and the South China Sea [ABSTRACT FROM AUTHOR]