LAUSR

The responses of the Indian and East Asian summer monsoons (ISM and EASM) to warming since the last deglaciation are controversial. Pollen results from a subalpine lake in the ISM area show that the Tsuga dumosa forest zone migrated at least 650 m upward during 18.6–7.1 kyr BP, indicating a gradual rise in mean annual temperature exceeding 3.9 °C. In response, grasses and deciduous and evergreen broad‐leaved trees successively colonized the mountainous environment. By contrast, the area around a lake in the EASM area was gradually occupied by temperate deciduous trees. In both areas, the maximum monsoonal precipitation occurred during 7.1–6.4 kyr BP, coinciding with peak Holocene warmth, but lagging the peak in Northern Hemisphere summer insolation by 3.9–4.6 kyr, due to delayed ice melting in northern high latitudes. Our results indicate the synchronous strengthening of the ISM and EASM in response to warming‐induced northward shifts in the Intertropical Convergence Zone.