Fifty miles south of the U.S.- Mexico border, the Colorado River Delta and its once-rich estuary wetlands --€” reduced by 95 percent since the river was restricted by dams --€” are now as parched as the surrounding Sonoran Desert. Peter McBride hide caption

itoggle caption Peter McBride

Researchers measure the Eklutna glacier in Alaska to see how long the water it provides will last. The glacier supplies Anchorage with both drinking water and hydro power. Annie Feidt for NPR hide caption

itoggle caption Annie Feidt for NPR

U.N. General Assembly President Nassir Abdulaziz Al-Nasser, United Nations Secretary General Ban Ki-Moon, Brazilian President Dilma Rousseff, Brazil's Secretary of the Conference Luis Figueiredo Machado and Rio+20 Secretary General Sha Zukang attend the closing ceremony of the Conference on Sustainable Development in Rio de Janeiro on Friday. Andre Penner/AP hide caption

itoggle caption Andre Penner/AP

Shell says it hopes to never need to use its new 300-foot-long, $100 million oil recovery ship named Nanuq for anything other than drills and training. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

A nearly 70-foot dock that was torn loose from a fishing port in northern Japan by last year's tsunami washed ashore on Agate Beach in Oregon. Marine scientists have found potentially invasive species among the 100 tons of marine life that traveled aboard the dock. Oregon Department of Parks and Recreation/AP hide caption

itoggle caption Oregon Department of Parks and Recreation/AP