Located in the South Pacific, the Carteret Islands are fighting a losing battle against the ocean. It's estimated the six islands will disappear into the water by 2015. Papua New Guinea plans to relocate the Carteret's 2,000 residents.

But a debate centers on what is causing these islands to disappear: Is global warming to blame, or are the islands sinking into the sea, or have the residents permanently damaged the reefs that help to protect the islands from the ocean?

CNN Image courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.