So I'm thinking of writing a novel and I've come up with this quick premise/background for a story. The idea would be that the melting of the Arctic ice-caps have caused oceans to rise to extreme heights and wipe out most of the major cities in the world. Those who have survived have been forced to move to the mountains where humanity is reverted back to the stone age. Food and resources are scarce and survivors have been split into clans who fight over each other to take whatever scraps they can find. The story would focus on a certain group of people who struggle to stay alive whilst looking for a way to restart human civilization.