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.

1986年至2004年间，蒙古高原夏季出现异常强烈的变暖，其速度是北半球平均陆地变暖的三倍。导致这种极端变暖的物理过程仍不清楚。在这里，我们表明，太平洋年代际涛动和大西洋数十年涛动的同步相移导致了蒙古高原的极端变暖，这不能仅用人为CO ₂的增加来完全解释。起搏器模型实验表明，太平洋年代际涛动和大西洋年代际涛动激发了大气波列，导致蒙古高原上空出现了高层反气旋环流。这种反气旋环流通过增强向下的太阳辐射而增加了地表变暖，而陆地-大气的正反馈又进一步促进了地表变暖。我们的结果强调了内部气候变率在驱动蒙古高原快速区域气候变化中的重要作用。