Most of these mid-Pacific islands are very little above sea level. So, if the ocean water rises 6 inches, it could take 10 or 20 feet away from the island. Same if the water level falls.
But they are atop volcanoes and even if those volcanoes are long dormant, we know enough about the earths crust to realize that some degree of upheaval and retreat is entirely possible. Let’s not forget that a few 7.x earthquakes have taken place in Indonesia (?) over the past few months and indeed, one today in Fiji. These are big damn earthquakes!
So to conclude that ocean water is rising or falling because that coconut tree over there used to be ten feet from the water and now it is only 3 feet from the water is....goofy. I don’t see how people can be so silly. Unless they are looking for study money.
Our Hawaii cruise ship visited Fanning Island in the Republic of Kiribati, 1000 miles south of Hawaii. This 9 mile by 6 mile atoll with a huge central lagoon averaged 10 feet above sea level!