Abstract Knowledge of the alpine glacier meltwater variations is fundamental prerequisite for understanding glacier dynamics and assessing the availability of freshwater resources. Glaciers on the Tibetan Plateau (TP) are sources of water for most major Asian rivers, but their melting history remains unclear, preventing in-depth understanding of their mechanisms. Here, we propose the authigenic carbonate δ 18 O from glacial lakes as a quantitative proxy to estimate variations of glacier meltwater. In the Western Kunlun Mountain, δ 18 O record at Guozha Co indicates that maximum glacier meltwater (− 28.62±25.76 Gt) occurred at 9.5–8.5 ka BP, and minimum glacier meltwater (24.53±25.02 Gt) at 1.3–0.5 ka BP. Nearly 20% of regional glaciers melted from the Early to Late Holocene, likely controlled by the summer temperature and accumulation of melting potential estimated by positive degree-day. Based on the projected temperature, this study suggests the TP glaciers likely face severe threats at the current rates of global warming.