Hydroclimatic anomalies in China during the post-Laki years and the role of concurring El Niño

Abstract

Arctic is warming at an alarming speed causing accelerated melting of Greenland and rising of sea level, and geoengineering by injecting aerosol into stratosphere (SAI) has been proposed as a backup approach to mitigate warming. However, studies suggest that SAI implementation may have adverse impacts on global especially monsoon precipitation, and Northern Hemisphere high-latitude injections may have disproportionally high effects than tropical injections. The 1783–1784 CE Laki eruption in Iceland provides an analogy to study the climatic and the subsequent socioecological responses to Arctic SAI, and China possesses a rich legacy of documents recording climatic disasters and describing their direct impacts on agriculture and society. Using the most recent summer precipitation reconstructions and the documentary data, this study presents a systemic analysis of the hydroclimatic anomalies as well as the societal and ecological consequences in China following the 1783–1784 CE Laki eruption. The results from multi-proxies show severe drought conditions in eastern China during the post-Laki years, accompanied by large scale locust breakout, famine and human pestilence. The drought and associated disasters first emerged in the North China Plain in 1784 CE, intensified and expanded to the middle and lower reaches of the Yangtze River in 1785 CE. The drought and famine stresses in China are part of the very unsettled climate conditions experienced across the Northern Hemispheric world during the 1780s. By isolating the ENSO-induced precipitation from the reconstructed summer precipitation changes, our results indicate that the Laki eruption did cause severe drought in monsoon China during the next three years. The drought responses in the 1783–1784 were largely counter-balanced by the wetting induced by the concurring strong El Niño event. The results help to enhance our understanding of the hydroclimate consequence of NH high latitude volcanic eruption in China, and the potential role climate internal variation such as ENSO may play in modifying volcanic-induced perturbation.