From what I understand, Tuvalu sinks at a rate of .5 inches a year, which means that perhaps in the next 30 years a large part of the island systems, which comprises of mostly low lying atolls and reefs, will have disappeared. The main islands itself may last much longer than its neighbors who occupy the same country, but not by much.
It will not be the current generation living there that will have to worry, it will be their children who will have to go move.
On another note, I'd like to point out that every volcanic island in both the Atlantic and Pacific is sinking. The reason being that volcanic islands, such as the Hawaiian Islands, are formed by basaltic lava flows, which over the eons build upon each other, layer by layer, until eventually they reach sea level. Mauna KEa, on the Big ISland, had to climb 16,000 feet before it pierced the ocean, and then another 16,000 to reach its current altitude of 32,000 feet above the sea floor. That's alot of lava.
Now if you've ever seen a smooth laval flow, you know that it forms caves and hollows inderground, lava tubes if you will. IT does the same thing under the ocean, and as millions of tons of rock build up, these hollows collapse from the weight. Now as long as the volcano is still erupting, it will continue to build, and the island will not appear to sink, however, as soon as the volcano dies out, the island's fate is set.
the enourmous wieght of the rock pushes down on the sea floor and the submarine lava rock, craks anf fractures it, as the islands begins to sink form its own weight. In time, a coral reef begins to develop, one lat creat memorial to a fantastic, majestic island. The island sinks more, and the coral reef grows. This process is already beginning on the island of Kauai, in the Hawaiian Islands. Near tunnels beach, a great reef is beignning to form, whcin in a million years will have circles 3/4 of the island if not more, though now it only covers a small area.
An island in the middle stages of its own death is Bora Bora Island in French Polynesia, part of the Archipel de la Societe, or Society Islands, whcih also contain the island of Tahiti.
All that is left of the original island of Bora Bora is the volcanic core, the peak if you will, rising charply out of the water, most of what the island was now lies underwatwer, and the reef, having submeserd rock on which to grow, has erected on of the most bautiful and mature coral reefs in the world. The barrier reef of Bora Bora has actualyl grown out of the water, creating a sand bar that encircles the entire island, and protects its shallow waters. Thsi in effect slows the erosion process by water on the island, leaving the wind, rain, and gravity to finish off the island.
And island in the last stages of its life woudl be Midway Atoll on the Hawaiian Islands. The actualy volcanic rock of the island lies over 500 feet below sea level, whicl the only land that remains above sea level is that created by the coral reefs. San Is, Eastern Is, and Spit Is, all found within the Midway Atoll, are piles of coral sand. Eventually they, too will fall below the ocean, leaving nothing but a reef, as evidenced by Maro Reef in the Leeward Hawaiian chain. Maro is nothing but a speck of coral in the middle of nowhere.
Thus an island's fate. A once proud, majestic island with towering volcanic peaks clothed in green splenour is lost, leaving behind warm shallow waters, protected by the ocean's wrath, and equally as bautiful, but even that eventually disappears, below the merciless sea.....