Over the last four decades, the area covered by lakes globally has grown by close to 18,000 square miles, an expanse nearly twice the size of Lake Erie. Scientists used satellite imagery and artificial intelligence to map 3.4 million lakes around the world between 1984 and 2019, finding that lake area grew as reservoirs expanded and rising temperatures melted glaciers and permafrost, particularly in Greenland, the Rocky Mountains, and the Tibetan Plateau.