Peking University, February 6, 2023: The Qinghai-Tibet Plateau is known for its cold and arid conditions. As a result of global warming, the greening of plateau vegetation and the retreat of the cryosphere have led to current decreases in surface albedo. However, it is still unclear how modern surface processes, which are characterized by the darkening of the plateau surface, affect and regulate regional glaciers and the Asian monsoon system.

To address this issue, Academician Piao Shilong’s research team from Peking University’s College of Urban and Environmental Sciences (CUES) together with Yao Tangdong’s team from the Institute of Tibetan Plateau Research (ITP), Chinese Academy of Sciences (CAS), jointly investigated the effects of plateau surface darkening on regional glaciers and the Asian monsoon system. The results show that under the high emission scenario, surface albedo is expected to decrease by 10.5% by the end of this century, significantly damaging the surface energy balance, and ultimately resulting in the increase of local temperature by about 0.24 degrees (Figure 1).

Figure 1: Feedbacks of albedo changes with reference to local climate in the Tibetan Plateau

The warming effect caused by the darkening of plateau surfaces intensifies regional glacier melting. By the end of this century, glacier volume loss is predicted to reach 6.9%, and will continue to increase to 25.2% when glaciers reach its climatic steady state (Fig. 2a). The loss of glaciers also presents significant spatial variation: glaciers in the central-western part of the plateau will retreat particularly sharply with long-term loss of more than 35% while glaciers in the southeastern parts will present a relatively stable loss of less than 7% (Fig. 2b).
 

Figure 2: Effect of surface darkening on regional glacier volume within the Tibetan Plateau

Surface darkening is also capable of strengthening the upward movement of air masses, increasing summer precipitation in South Asia and further exacerbating the current phenomenon of "southern flooding and northern drought" in East Asia (Figure 3). 
 

Figure 3: Effects of surface darkening on the Asian monsoon system in the Tibetan Plateau

The above findings are important for the accurate understanding of plateau surface processes under the influences of global warming and provide significant scientific support for the accurate prediction of the changes of the Asian monsoon system. 

The research results were published in Nature Communications on January 3, 2023 under the title of "Regional and tele-connected impacts of the Tibetan Plateau surface darkening."

Written by: Niki Qiu
Edited by: Meng Bin
Source: College of Urban and Environmental Sciences