Abrupt Contraction of the Indo-East Asian Monsoons Ended the Holocene Humid Period

Abstract

Rain-belt migration, and in particular monsoon migration, are a cardinal, yet under-constrained aspect of climate change. Here, we present a new lake-level record from a closed-basin lake in northern China and a compilation of available lake level records from closed-basin lakes located at the northern margins of East Asian and Indian monsoon regions. These data show that ca. 6 ka ago, changes in water availability, as recorded by the surface areas of the closed-basin lakes, shrunk dramatically, within a few decades, and have not been restored to their pre-6 ka sizes since. These data imply that the Indo-East Asian monsoon systems underwent a large coeval southward contraction, which preceded the gradual decline in insolation forcing, and abruptly ended the Holocene Humid Period (HHP). This new compilation enables to constrain potential feedback mechanisms involved in the early termination of the HHP at the monsoon fringes.