Mass-wasting-inferred 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 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 transformation lags
the global ice volume (sea level) change by 8–15 kyrs.