Response of Two Glaciers in Different Climate Settings of the Tibetan Plateau to Climate Change Through Year 2100 Using a Hybrid Modeling Approach

Glaciers in High Mountain Asia (HMA) have been continuously retreating over the past four decades under global warming, affecting water availability for humans and ecosystems. However, the potential differences in mass loss and glacier runoff between maritime and continental glaciers of HMA are poorly understood. To understand the response of both types of glaciers to climate change, this study developed a hybrid modeling approach suited to data-sparse regions, and applied the proposed approach to the Parlung No. 94 Glacier (a maritime glacier) and the Dongkemadi Glacier (a continental glacier) to project glacier change under climate change. Results show that the maritime glacier has a higher balance amplitude and more negative net balance than the continental glacier. Forced by model outputs from the sixth phase of the Coupled Model Intercomparison Project, both glaciers are projected to melt almost entirely by year 2100 under the highest emission scenario (SSP585). The projected year by which the continental glacier's volume (area) is expected to halve, relative to year 2018, is about 5-11 (14) years later than that of the maritime glacier due to lower glacier retreat rates. Glacier runoff projections indicate that the peak glacier runoff occurs later and is larger for higher emission scenarios and for the continental glacier than the maritime glacier. The peak water year for the Dongkemadi Glacier is projected to occur about 24-35 years later than for the Parlung No. 94 Glacier, for which it is expected to occur by the mid-21st-century.