Mass‐Wasting‐Inferred Dramatic Variability of 130,000‐Year Indian Summer Monsoon Intensity From Deposits in the Southeast Tibetan Plateau

Abstract

AbstractA large proportion (∼80%) of the Indian subcontinent's precipitation comes from the Indian summer monsoon (ISM), which influences one‐fifth of the world's population. A long‐term reliable proxy for ISM is fundamental to understanding previous global climate change. We establish a mass‐wasting‐inferred proxy to examine the paleo‐hydrogeology (river undercutting history) of the Southeast Tibetan Plateau and reconstruct the dramatic variability of ISM intensity (precipitation) in the past 130,000 years. Our data suggest that mass‐wasting events, which provides us sufficient samples for paleoclimate research, are prone to dramatic climate changes, especially extreme climate environments. The Southeast Tibetan Plateau was subjected to at least four distinct ISM intensity phases in the past 130,000 years. We conclude that ISM intensity has a cyclicity featured by the Earth's orbit with obliquity, and that ISM intensity transition lags the global ice volume (sea level) change by 8–15 kyrs.