What anime is this?
Well, the title shows an English translation as "Children of the Whales" (Google Translate- "The Sons of the Whale Sing on the Sand"); the website given in the video indicates a TV show starting on October, and some of the other images show it might be based on a light novel series.
Time for more knowledgeable people to chime in.
"Based on Umeda Abi's shoujo manga.
Chakuro is the 14-year-old archivist of the Mud Whale, a nigh-utopian island that floats across the surface of an endless sea of sand. Nine in ten of the inhabitants of the Mud Whale have been blessed and cursed with the ability to use saimia, special powers that doom them to an early death. Chakuro and his friends have stumbled across other islands, but they have never met, seen, or even heard of a human who wasn't from their own. One day, Chakuro visits an island as large as the Mud Whale and meets a girl who will change his destiny."
This is something I've been looking forward to. And, I hope Funimation can get it for use.