Recent pronounced warming on the Mongolian Plateau boosted by internal climate variability

Exceptionally strong summertime warming occurred over the Mongolian Plateau between 1986 and 2004, at a rate that was three times the average terrestrial warming in the Northern Hemisphere. The physical processes responsible for this extreme warming remain unclear. Here we show that the synchronous phase shift of the Interdecadal Pacific Oscillation and the Atlantic Multidecadal Oscillation contributed to this extreme Mongolian Plateau warming, which cannot be fully explained by the increasing anthropogenic CO₂ alone. Pacemaker model experiments show that the Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation excited an atmospheric wave train, resulting in an upper-level anticyclonic circulation over the Mongolian Plateau. This anticyclonic circulation increased surface warming by enhancing downward solar radiation, and the surface warming was further boosted by positive land–atmosphere feedbacks. Our results highlight the important role of internal climate variability in driving rapid regional climate change over the Mongolian Plateau.