Mid-Pliocene Asian Monsoon Intensification And The Onset Of Northern Hemisphere Glaciation

In a new study published in the journal Geology, Zhang et al. present a key low-latitude climate record, the high-resolution Asian monsoon precipitation variability for the past five million years, reconstructed from South China Sea sediments. Their results, with supporting evidence from other records, indicate significant mid-Pliocene Asian monsoon intensification, preceding the initiation of NHG at about 2.7 million years ago. The correlation between the monsoon record and marine calcium isotopes indicates that the 1.4-million-year-long monsoon intensification probably enhanced Asian continental erosion and chemical weathering.

Elevated chemical weathering and organic carbon burial probably lowered the contemporary atmospheric CO₂, and the CO₂ drop may have triggered the NHG onset as suggested by a recent study. As opposed to previous studies, here Zhang et al. propose a low-latitude-driven NHG glaciation scenario.