Precipitation change
The demise of the Ming Dynasty (1368–1644) and the rise of the Qing Dynasty (1644–1912) marked an epochal moment in Chinese and world history. Attention has been given to the North China droughts during 1627–1643 that destabilized the Ming Dynasty. However, there is little attention paid to how climate influenced the rise of a minority Manchu state in Northeast China and its conquest of the Ming. Here, we find that contrasting climate conditions between North and Northeast China persisted over a six-decade period (1581–1644), which diversely affected economic, societal, and political changes at the regional level. Five successive megadroughts ravaged North China, while relatively wet and mild climate conditions prevailed in the Manchu homeland of Northeast China. Furthermore, in the early decades of Manchu rule in North China (1645–1680), increased precipitation facilitated the Qing Dynasty’s consolidation. Reconstructions and climate model simulations revealed that these unusual climatic patterns were influenced by the centennial variation of clustering El Niño-Southern Oscillation (ENSO) events and were amplified by the Little Ice Age cooling. These findings shed light on how long-term contrasting future climate changes could lead to divergent socioeconomic responses, potentially increasing the risk of conflict between neighboring states.
So how are ENSO impacts likely to evolve in the coming decades?
“Extreme El Niño and La Niña events may increase in frequency from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios,” McPhaden said. “The strongest events may also become even stronger than they are today.”
In a warming climate, rainfall extremes are projected to shift eastward along the equator in the Pacific Ocean during El Niño events and westward during extreme La Niña events. Less clear is the potential evolution of rainfall patterns in the mid-latitudes, but extremes may be more pronounced if strong El Niños and La Niñas increase in frequency and amplitude, he said.
Some ENSO impacts are already being amplified, such as the extensive coral bleaching and increases in tropical Pacific storm activity observed during the 2015-16 El Niño. ENSO is expected to impact tropical cyclone genesis in the future as it does today in the Atlantic, Pacific and Indian Oceans, but precisely how is still an open question.
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