The Third Pole (TP) is the world’s largest highland and has one of the biggest reservoirs of glacier ice mass and snow cover on the Earth. Three major Asian rivers (the Indus, Ganga and Brahmaputra) are nourished by the melting of glaciers and snow in Central Himalaya, which are inevitable for the socioeconomic sustainability and water security of South Asia. Here, we investigate the long-term (1980–2020) changes in snow depth and precipitation in TP, where major precipitation occurs in the form of rainfall in summer, and snowfall in winter and spring. The seasonal mean snow depth is deep (≥1 m) in winter and shallow (≤0.2 m) in summer. The average snowmelt and snow water equivalent are higher in the central and western Himalaya and Karakoram ranges in spring, which are the regions with most glaciers in TP. There is a significant positive trend in total precipitation, about 0.01–0.03 mm d⁻¹ yr⁻¹ in the central and eastern TP during the South Asian Summer Monsoon for the 1980–2020 period. Snowmelt is also increasing (>0.5 × 10⁻³mm yr⁻¹) in the western Himalaya during spring, which is consistent with the temperature rise (0.04–0.06 °C yr⁻¹) there. In addition, there is a notable increase in the annual mean glacier melt (here, the water equivalent thickness) in TP (−1 to −5 cm w.e. yr⁻¹), with its highest values in the eastern and central Himalaya (−3 to −5 cm w.e. yr⁻¹), as estimated for the period 2003–2020. On top of these, by the end of the 21^st century, the Coupled Model Intercomparison Project Phase 6 (CMIP6) projections show that there would be a significant decrease in snow depth and an increase in temperature of TP in all shared socioeconomic pathways (SSPs). Henceforth, the increasing trend in temperature and melting of snow/glaciers in TP would be a serious threat to the regional climate, water security and livelihood of the people of South Asia.

第三极（TP）是世界上最大的高地，拥有地球上最大的冰川冰块和积雪库之一。亚洲三大河流（印度河、恒河和布拉马普特拉河）的水源来自喜马拉雅山脉中部冰川和积雪的融化，这对于南亚的社会经济可持续性和水安全来说是不可避免的。在这里，我们研究了青藏高原雪深和降水的长期（1980-2020）变化，其中主要降水形式为夏季降雨，冬季和春季降雪。季节平均积雪深度冬季深（≥1 m），夏季浅（≤0.2 m）。喜马拉雅山中西部和喀喇昆仑山脉春季平均融雪量和雪水当量较高，是青藏高原冰川最多的地区。 1980—2020年南亚夏季风期间，青藏高原中东部地区总降水量呈显着正向变化趋势，约为0.01—0.03毫米·d ⁻¹ ·年 ⁻¹ 。春季期间喜马拉雅山西部的融雪量也在增加（每年 >0.5 × 10 ⁻³ 毫米 ⁻¹ ），这与气温上升（每年 0.04–0.06 °C ⁻¹ ）那里。此外，青藏高原年平均冰川融化（此处为水当量厚度）显着增加（-1至-5厘米w.e. yr ⁻¹ ），其最高值出现在东部和东部地区。喜马拉雅山中部（-3 至 -5 厘米 w.e. 年 ⁻¹ ），根据 2003 年至 2020 年期间的估计。除此之外，到21世纪末，耦合模式比对项目第六期（CMIP6）预测显示，青藏高原雪深将显着减少，气温将显着升高。所有共享的社会经济路径（SSP）。 今后，青藏高原气温上升和冰雪融化将严重威胁区域气候、水安全和南亚人民的生计。