Recent heat wave across the Yunnan-Guizhou plateau and its impact on alpine lakes

Lakes are integral components of the global terrestrial ecosystem, with lake water temperature serving as a key parameter influencing the physical and biogeochemical processes within lake systems. In recent years, however, the intensification of global warming has significantly impacted lake water temperatures, resulting in a range of environmental consequences, including the increased frequency and intensity of algal blooms (ABs). This study focused on the Yunnan-Guizhou (YG) Plateau, a region sensitive to climate change, as the research area. The warming trends of the whole area were analyzed since the establishment of 234 meteorological stations. The trends in land surface water temperature (LSWT) and the ABs risk in 14 plateau lakes over the past 25 years were assessed using MODIS land surface temperature dataset, water quality monitoring data, and key climatic parameters, an evaluation framework was developed using machine learning algorithms (random forest, RF) and logistic regression (LR) models. The main findings of this study are as follows: 1. The YG Plateau has undergone significant warming since 1960 (0.20 °C/10a), with the most rapid temperature increase occurring after 2000 (0.37 °C/10a) and 2023 recorded as the warmest year on record; 2. All 14 lakes in the region have exhibited significant warming, although the rate of increase in LSWT is lower than that of the surrounding air temperature (0.26 °C/10a lower); 3. The ABs risk range is influenced by the lakes' water quality characteristics, all lakes have shown a significant increase in higher risk levels of ABs over the past 25 years. This study aims to provide a scientific basis for the development of climate change adaptation strategies and holds practical significance for the management of local aquatic environments.