More than half a percent of Earth’s nonglaciated land surface—about 773,000 km2—is covered with rivers and streams, according to a new analysis of satellite images. The estimate, which appears today (June 28) in Science, is about 44 percent higher than the previously accepted number.
“If you look around the world, rivers look different from place to place,” coauthor George Allen of Texas A&M University tells Gizmodo. “They might be braided, or sinuous, or meandering. And for the most part, current technology doesn’t take into consideration the actual morphology of rivers. This data set is the first of its kind to do this at a global scale on high resolution.”
Allen and Tamlin Pavelsky of the University of North Carolina, Chapel Hill, used software to pick out and measure the surface area of rivers in images from NASA’s Landsat satellite. They found that Earth’s rivers and streams collectively cover an area ...
