About 20,000 years ago, the islands of what is now Tuvalu were just above sea level, just as they are today. Since that time, sea level has risen more than 400 feet (130 meters) and yet, the islands remained above sea level.
The reason that these islands grew is a geologic process known as
"accretion." This process transfers
sediment from the beachface to the island surface and allows the islands to keep up with rising seas. In fact, over the last four decades, there has been a net increase in land area of the islands of nearly 3 percent (33 acres).