Oceanic repeaters boost the global climatic impact of the Tibetan Plateau.

ABSTRACT

The topography of the Tibetan Plateau (TP) has shaped the paleoclimatic evolution of the Asian monsoon. However, the influence of the TP on the global climate, beyond the domain of the Asian monsoon, remains unclear. Here we show that the Pacific and Atlantic Oceans act as efficient repeaters that boost the global climatic impact of the TP. The simulations demonstrate that oceanic repeaters enable TP heating to induce a wide-ranging climate response across the globe. A 1 °C TP warming can result in a 0.73 °C temperature increase over North America. Oceanic repeaters exert their influence by enhancing the air-sea interaction-mediated horizontal heat and moisture transport, as well as relevant atmospheric circulation pathways including westerlies, stationary waves, and zonal-vertical cells. Air-sea interactions were further tied to local feedbacks, mainly the decreased air-sea latent heat flux from the weakening air-sea humidity difference and the increased shortwave radiation from sinking motion-induced cloud reduction over the North Pacific and Atlantic Oceans. Our findings highlight the crucial influence of TP heating variation on the current climate under a quasi-fixed topography, in contrast to topography change previously studied in paleoclimate evolution. Therefore, TP heating should be considered in research on global climate change.