CMIP5 climate projections for the Yamzhog Yumco Basin: an environmental testbed for alpine lakes

As projections of future climate change rely on global climate model (GCM) results, the performances of five GCMs included in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) are compared with ground observations (temperature and precipitation, 1961–2005) in southern Qinghai-Tibetan Plateau (TP). The comparison suggests that the models capture the climatological patterns of the observed climate but with cold and wet biases. Future (twenty-first century) trends based on the GCMs’ projections produced a warming trend, and the annual precipitation of the multi-model mean is generally projected to increase. Relative to the 1986–2005 mean, both the average annual temperature and precipitation of the five GCMs are projected to increase in the short term (2016–2035), medium term (2046–2065), and long term (2081–2100) under the scenarios of rcp2.6, rcp4.5, and rcp8.5. While the temperature and precipitation changes and the difference among scenarios become substantial as time evolves. Possible regional climate change impact on the Yamzhog Yumco Basin in southern TP is demonstrated by future lake area estimates based on a minimalist parametric model and the average annual precipitation predicted by the five GCMs: the lake area of Yamzhog Yumco (including Kongmu Co) will expand under the three scenarios for the three periods relative to the 1974–1993 mean. It is expected to obtain more reliable local information with the downscaling of GCM simulations to regional scales by using regional climate models for assessing regional hydrological impacts in more detail for further studies in the southern TP.