Or something darker.. R'yleh where dead Cthulu lies dreaming is out there near Point Nemo too ;)

Or something even darker than that...

What if this story took place on a planet where the inhabitants collectively decided to value at-all-costs economic growth over a sustainable ecosystem, resulting in a situation where they were losing over a trillion metric tons of ice per year and that is what caused the mysterious island to be revealed...?

That scenario is so unrealistic that nobody would be able to suspend their disbelief enough to get into it.