Global warming has led to permafrost degradation worldwide. The Qinghai‐Tibet Plateau (QTP) hosts most of the world's alpine permafrost, yet its impending changes remain largely unclear, thereby affecting regional hydrological and ecological processes and the global carbon budget. By employing a land surface model adapted to simulate frozen ground, and using state‐of‐the‐art multi‐model and multi‐scenario data from the Coupled Model Intercomparison Project Phase 6, changes in permafrost distribution and its thermal regimes on the QTP are systematically predicted under various shared socioeconomic pathways (SSPs). Projections for SSP2‐4.5, SSP3‐7.0, and SSP5‐8.5 show that most of the continuous permafrost region of the QTP will persist through 2050. Much of the permafrost is likely to degrade in the late 21st century, with projected area losses of 44 ± 4%, 59 ± 5%, and 71 ± 7%, respectively, by 2100. In particular, the Three Rivers Source region in the central eastern part of the QTP is a key area of permafrost degradation, where permafrost is most vulnerable and degradation occurs earliest. The mean annual ground temperature of QTP permafrost will increase by 0.8 ± 0.2°C, 2.0 ± 0.3°C, and 2.6 ± 0.3°C under SSP2‐4.5, SSP3‐7.0, and SSP5‐8.5, respectively, and the active layer thickness will increase by 0.7 ± 0.1 m, 1.5 ± 0.3 m, and 3.0 ± 1.0 m, respectively. The surviving permafrost under SSP3‐7.0 and SSP5‐8.5 will be thermally unstable, which is a clear warning sign of complete disappearance. The analysis of permafrost sensitivity to climate change signifies that alpine permafrost on the QTP has low resilience to climate change, in contrast to permafrost in pan‐Artic high latitudes.

Winter warming is fast than summer warming on the Qinghai‐Tibet Plateau (QTP). However, no assessment of winter warming effects on permafrost has been attempted. Here we conducted hypothetical control experiments and used the Noah land surface model to evaluate the impacts of winter warming on the QTP permafrost. The results show that air temperature in winter (November–April) was increasing at a rate of 0.66 °C/decade during 1980s−2000s, over double that in summer (May–October). The mean annual ground temperature of permafrost increased by 0.13 °C/decade. The summer warming dominated the variations in thermal regime of permafrost before 2000. After that, the influence of winter warming on permafrost thermal regime has gradually grown and exceeded that of summer warming. Winter warming has amplified the thermal degradation of permafrost. Our findings reveal that alpine continuous permafrost on the northern QTP has experienced a prominent regional warming due to rapid winter warming since 2000.

Climate warming is thermally degrading permafrost. The climate warming over the Qinghai‐Tibet Plateau (QTP) is characterized by obvious seasonality and stronger winter warming in comparison with summer warming in 2000s. The contributions of seasonal climate warming to permafrost thermal responses remain unknown. Here, we isolated the seasonal warming contributions to permafrost thermal regimes through contrasting a series of specially designed numerical experiments that were composed of decadal seasonal data segments. The results reveal that permafrost thermal regime is highly sensitive to winter temperature change. Permafrost in the Three River Source region and on the Qiangtang High Plateau has undergone remarkable thermal degradation in the 2000s due to winter warming. It was estimated that each degree of rising in air temperature in summer could lead to an average increase of 0.35 m in the active layer thickness (ALT) and of 0.20°C in the mean annual ground temperature (MAGT), while for 1° winter warming, the active layer thickens by 0.16 m and the MAGT increases by 0.13°C. However, the overall impacts of winter warming have exceeded summer warming in 2000s due to a triple warming rate in winter than that in summer in this period.

Thermokarst lakes, serving as significant sources of methane (CH₄), play a crucial role in affecting the feedback of permafrost carbon cycle to global warming. However, accurately assessing CH₄ emissions from these lakes remains challenging due to limited observations during lake ice melting periods. In this study, by integrating field surveys with machine learning modeling, we offer a comprehensive assessment of present and future CH₄ emissions from thermokarst lakes on the Tibetan Plateau. Our results reveal that the previously underestimated CH₄ release from lake ice bubble and water storage during ice melting periods is 11.2 ± 1.6 Gg C of CH₄, accounting for 17 ± 4% of the annual total release from lakes. Despite thermokarst lakes cover only 0.2% of the permafrost area, they annually emit 65.5 ± 10.0 Gg C of CH₄, which offsets 6.4% of the net carbon sink in alpine grasslands on the plateau. Considering the loss of lake ice, the expansion of thermokarst lakes is projected to lead to 1.1–1.2 folds increase in CH₄ emissions by 2100. Our study allows foreseeing future CH₄ emissions from the rapid expanding thermokarst lakes and sheds new lights on processes controlling the carbon-climate feedback in alpine permafrost ecosystems.

Global warming has caused widespread permafrost degradation, but the geographic regularity of permafrost degradation is unknown. Here, we investigated the three-dimensional features of future permafrost degradation on the Qinghai-Tibetan Plateau. Our findings show that permafrost degradation under shared socioeconomic pathways (SSPs) has obvious three-dimensional characteristics. In comparison to latitude and aridity, permafrost degradation is closely related to elevation, i.e. it slows with elevation, a phenomenon known as elevation-dependent degradation. The pattern of elevation-dependent degradation is consistent across four subzones and is strongly linked to thermal conditions that vary with elevation. Under SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, remarkable elevation-dependent warming (EDW) is observed at 3600–4900 m, but changes in mean annual ground temperature of permafrost and EDW as altitude rises are anti-phase. Under any SSP, the magnitude of mean annual air temperature along altitude belts determines the degree of permafrost degradation (R ² > 0.90). This research provides new insight on the evolution of permafrost.