High-latitude climates regulate Holocene precipitation in the northernmost East Asian monsoon region

The East Asian Summer Monsoon (EASM) is a subtropical monsoon system extending northward to approximately 55°N, distinguishing it from tropical monsoon systems that are primarily driven by low-latitude summer insolation. This geographic extent makes the EASM more susceptible to influences from high northern latitude climates. However, the extent and mechanisms by which high-latitude climates influence EASM precipitation during the Holocene remain poorly understood. This study integrates a new precipitation record with existing geological evidence and paleoclimate model simulations, consistently demonstrating a long-term, trendless pattern of Holocene precipitation at the northernmost margin of the EASM. This behavior stands in contrast to the declining precipitation trends observed in more southern EASM regions, which are primarily driven by decreasing low-latitude summer insolation. Simulation experiments indicate that a reduction in summer precipitation was offset by a corresponding increase in non-summer precipitation from the early to middle Holocene. We attribute this stable precipitation pattern to the combined effects of enhanced non-summer precipitation driven by high-latitude forcings and decreased summer precipitation governed by low-latitude insolation. These findings advance our understanding of the interplay between high- and low-latitude forcings in shaping regional variations in EASM precipitation. Continued melting of Northern Hemisphere ice sheets and sea ice in the near future could enhance precipitation in the northernmost East Asian monsoon region, potentially benefiting regional ecosystems, agriculture, and animal husbandry.