Since the mid-19th century, in fact, Tangier has seen more than half of its square footage vanish into the surrounding seas. Nowadays, the island covers a little over 1 square mile, and annually a further 15 feet of its coastline is disappearing beneath the ocean. Without a reversal in climate change, then, scientists say Tangier could be underwater in a quarter-century, which will leave residents needing to create new lives on the mainland. Other islands in danger of suffering the same fate include the Seychelles and the Maldives.
And yet, with many islands facing the threat of encroaching waters, geographers have also noticed new ones popping up, too. For instance, the Pakistani city of Gwadar experienced a 7.7-magnitude earthquake in September of 2013. In the aftermath, the island of Zalzala Koh rose from the waters just off of the coast.
Zalzala Koh didn’t last long, however – by 2016, it had sunk back into the waters. Shelly Island, off the coast of North Carolina’s Outer Banks region, also appeared and disappeared quickly. In April of 2017 the extra-large sandbank started to form thanks to strong winds and a relatively mild storm season. But by February of 2018, the island had been submerged.