New findings from studying over two decades of satellite observations reveal that Earth's continents have experienced unprecedented freshwater loss since 2002, driven by climate change, unsustainable groundwater use and extreme droughts. The study, led by Arizona State University and published today in Science Advances, highlights the emergence of four continental-scale "mega-drying" regions, all located in the northern hemisphere, and warns of severe consequences for water security, agriculture, sea level rise and global stability.