Global assessment and hotspots of lake drought

Many lakes have exhibited substantial variability in recent years, making “lake drought” a growing concern. However, there is no established framework for identifying and studying lake droughts. Here, we propose a reliable definition for it and provide a global assessment of over 160,000 lakes (≥1 km2) using monthly area data from 1985 to 2018. Our findings show that 15.7% of lakes have experienced statistically significant increasing trends in drought frequency (p < 0.05), with hotspots in the Southern United States at 52.7% and Southeast Australia at 70.4%. Furthermore, we identify two severe lake drought events in the Southern United States (2012–2014) and Southeast Australia (2007–2010), posing dramatic threats to water supplies, biodiversity, and ecological health. Rising trends in lake drought are driven by increasing temperature, vapor pressure deficit, and factors associated with the lake water cycle, such as precipitation deficit, increased evaporation, and excessive water withdrawal. During 1985–2018, over 15% of lakes experienced increasing drought frequency, with hotspots in the southern US and southeast Australia posing significant threats to water supplies, biodiversity, and ecological health, according to a global assessment of over 160,000 lakes using monthly lake area data.