This is from a recent Lindblad-National Geographic trip to French Polynesia to some very remote islands including
Millennium Atoll, Flint Island and Rangiroa.  The undersea specialist was able to see extensive changes is the lagoon
of Millennium Atoll from his visit only 3 years ago. All the "clam towers" were dead and coral bleaching was present.
The southern line islands belong to the Republic of Kiribati. You can see from the map in the video that the country is
vast and is made up predominantly of atolls. The government is buying land in New Zealand and elsewhere in the hope
to be able to relocate as their country disappears with the rising ocean.