Amplified Expansion of Permafrost-Affected Lakes on Tibetan Plateau impacted by the Triple-Dip La Niña Event (2020–2023)

In the year 2023, much of the world experienced record-breaking extreme heat and drought following the Triple-Dip La Niña. However, the Tibetan Plateau witnessed anomalous wetting but milder cooling, and the impact of these changes on the dynamics of permafrost-affected lake areas remains unclear. Here, we integrated lake maps from 2020 to 2023 and permafrost distribution to analyze the spatiotemporal heterogeneity of permafrost-affected lakes over Tibetan Plateau. The results showed that the area of permafrost-affected lakes increased by 2.1 % year^-1 (1245.89 km²) from 2020 to 2023 over Tibetan Plateau, representing a 25% higher growth rate compared to the period from 1990 to 2020. Moreover, the expansion of permafrost-affected lakes exhibited strong spatial heterogeneity. Specifically, the 95% (1159.48 km²) of the total increase area occurred in endorheic basins with larger permafrost coverage and increased net precipitation (precipitation minus evaporation). In contrast, the exorheic basins with fragmented permafrost coverage instead exhibited a markable slowdown expansion by only 0.98% year^-1, due to the decrease in net precipitation. These findings highlighted the compounded effects of extreme precipitation events and permafrost degradation on lake expansion over Tibetan Plateau.