A time in the future where, for whatever reason, the Earth has become entirely or partially flooded by rising seas. This kind of setting can be brought about by various reasons, although most involve some kind of natural or unnatural disaster. In modern fiction, this often takes the form of a Green Aesop about Global Warming, as potentially catastrophic rise in sea levels are a very real danger of greenhouse conditions melting the polar ice caps and sending their meltwater into the ocean.