Extreme Tibetan Plateau cooling caused by tropical volcanism

Abstract The Tibetan Plateau (TP) is experiencing a significant imbalance of glacier mass as a result of atmospheric warming. The warming on the TP has generally been attributed to both climate internal variability and anthropogenic forcing. Here we show that the recent five large tropical volcanic eruptions since 1863 have caused an extreme TP cooling up to -0.80 K during the first boreal winter following the eruptions, much larger than the global average terrestrial cooling of -0.30 K. The extreme TP cooling response of -0.79 K to tropical eruptions is simulated by the multimodel ensemble mean of the Phase 6 Coupled Model Intercomparison Project when realistic sea surface temperatures are specified for the atmospheric models, and it is much larger than the direct aerosol cooling of -0.36 K simulated by the historical runs. The positive North Atlantic Oscillation during the post-eruption winter plays the key role in amplifing the TP cooling through atmospheric teleconnection, which overwhelms the warming response associated with the frequently occurring El Niños. Results from this study put into perspective the potential contribution of volcanic activity to certain TP cooling.