Mass-wasting-inferred Dramatic Variability of 130,000-year Indian Summer Monsoon Intensity from Deposits in the Southeast Tibetan Plateau

A 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
paleohydrogeology (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.