National Geographic created this map to show how potential relative sea level rise in the Chesapeake Bay may make certain areas vulnerable to inundation. The Chesapeake Bay is the largest estuary in the United States and one of the world’s most biologically rich and productive. For decades, because of the high population of its watershed, the bay has been degraded by toxic contaminants, excessive nutrients, and sedimentation that have shrunk critical habitats. Now climate change threatens to undo conservation efforts. Bay water is two degrees warmer than in the 1960’s, and while global seawater has risen at the rate of six inches in 100 years, the bay has risen nearly a foot because of its naturally subsiding coastal land.