Natural lakes dominate global water storage variability

Although land surface water only covers a small portion(～3.7％)of our planet,it plays many essential roles:e.g.,freshwa-ter storage,industrial consumption,agricultural irrigation,and biodiversity maintenance[1,2].Water storage variability is associ-ated with various natural processes and human activities on the Earth[3,4]and it is well known that reservoir regulation is the most widely distributed and fundamental human activity capable of altering the global water cycle.In recent years,through reservoir regulation,humans have been able to obtain more freshwater from the Earth's surface,with great benefits to human wellbeing.Cur-rently,however,the extent to which human activities affect the global water cycle remains unknown.As a result,there is an urgent need to quantify and understand the role of human activities in the global water cycle to ensure that freshwater resources are man-aged sustainably at the global scale.