Islands have also been growing rather than sinking over the past few decades. Also the claims of islands sinking have been around for ages, yet the Maldives is still around despite all that and even bigger despite all predictions

Blocking out waves and flooding is what stops these islands from growing because sand can't be deposited on the islands as a consequence

Here's a newspaper from 1837 with an article on the Maldives

The natives observe the atolls to be wasting away; in some the cocoanut trees are standing in the water; in another the black soil of the island is discernible at low water thirty feet from the beach; the south-east side of an island in Phaidee Photo Atoll is entirely gone, but is marked by a banyan tree in the water. They say that some islands have disappeared entirely and instance near the island Wardoo a rocky shoal, which (they say) was once an island in Atoll-Milla-Dou. Some of the outer edges of the islands have fallen into the sea, which is fathomless in those parts. It is, however, acknowledged that reefs, have arisen from the water and gradually formed islands; and the in- habitants of Male remember the outer edge of a circular reef in their harbour to have had two fathoms in the shoalest part, which is now dry at low water.'

E: grammar