Land Surface Changes Induced a Strengthened Indian Summer Monsoon in the Mid‐Pliocene Warmer Climate

Indian summer monsoon (ISM) change under global warming is a serious concern because of its widespread socio‐economic impacts. Under the greenhouse gas (GHG)‐induced near future warming, climate models project a weakened ISM circulation, limiting the rate of monsoon rainfall increase. However, we find that climate models commonly simulate a strengthened ISM circulation in favor of ISM rainfall increase during the mid‐Pliocene that is often considered analogous to the ongoing anthropogenic warming. This enhanced ISM circulation change is physically consistent with a dramatically strong warming over Eastern Eurasia, which strengthened the mid‐upper tropospheric meridional temperature gradient across the ISM region. Sensitivity experiments reveal that such an Eastern Eurasian warming was closely associated with the northern continental greening via local vegetation‐albedo feedback. Our results highlight that the land cover changes, rather than GHG forcing, dominated this regional‐scale warming and resultant regional hydrological cycle in the mid‐Pliocene warm period.