Paleoclimates inform on a weakening and amplitude-reduced East Asian winter monsoon in the warming future

Abstract

Abstract The East Asian winter monsoon (EAWM) has significant impacts on the weather and climate, and subsequently on the economy and society, in East Asia during boreal winters, and its projection into the future is scientifically and practically significant. However, projections relying on geological EAWM reconstructions, which can compensate for instrumental record limitations, are still lacking and urgently needed. It is more promising to conduct prediction under the background of not only instrumental but also geological changes in the EAWM. We used grain-size records from four high-resolution, chronologically well-defined loess sections on the Chinese Loess Plateau to represent past EAWM intensity and its amplitudes. Our results show that the EAWM is weaker and has lower amplitudes during warm periods than during cold stages at various time scales. Moreover, instrumental records reveal that the EAWM shows a weak level and reduced interannual amplitudes after the mid-1980s under the context of global warming. We propose that the EAWM will experience long-term weakening and reduced (e.g., interannual) amplitudes under 21st century global-warming scenarios.