http://www.sciencemag.org/news/2018/07/new-map-reveals-just-13-world-s-oceans-are-still-wild

“Wilderness” might bring to mind sprawling forests in national parks like Yosemite and Yellowstone, but there is a second wilderness—the world’s seas. Now, for the first time, researchers have systematically mapped out that wilderness (in blue, above) by identifying what fraction of the ocean remains largely unaffected by humans. Their answer? Just 13%.

To produce the map, the team didn’t conduct on-the-sea-floor surveys, but instead investigated the regional impacts of 15 human-caused ecosystem stressors, including pollution, fishing, and commercial shipping, all of which have been shown to degrade habitats by disrupting food chains and reducing biodiversity. Areas that were the least affected by all 15 stressors qualified as wilderness. When the numbers were in, just 13% of the ocean—or 54 million square kilometers—met that definition, the researchers report today in Current Biology.