Climate projections for Himalaya–Tibetan Highland

Abstract

The fidelity of 47 CMIP6 climate models in simulating the monsoon (June to August) over Himalaya–Tibetan Highland (HTH) is examined for the historical period (1975-2014) and 8 best performing models have been identified. It is found that the multi-model mean of 47 CMIP6 models (MMM) still exhibits systematic cold and wet biases for Tas and precipitation, respectively during the historical period. On the contrary, the multi-model mean of 8 best models (MM8) could simulate the spatial distributions better than MMM by alleviating the wet biases (~2 mm day⁻¹) over the southern and eastern HTH, whilst no significant improvement is noted in near surface temperature (Tas). The simulated decreasing (increasing) trends for Tas (precipitation) are found to be less satisfactory in both the MMMs. The MM8 also shows an improved annual cycle of Tas and precipitation over the HTH, accompanied by a better representation of mid-tropospheric temperatures and upper-level anticyclone. The MM8 was considered to perform the future projections, it is noted that the future projections show a widespread warming of 0.6–0.9°C decade⁻¹ and an increased precipitation of 0.3–0.5 mm day⁻¹decade⁻¹ across the Himalayan foothills and southeastern parts of HTH by the end of the twenty-first century under the worst case scenario (SSP585). This insightful information would assist the policy and decision makers in making informed decisions and adaptation strategies against the far-reaching impacts of climate change.