Remember Kevin Costner's gills in Waterworld? They could come in useful should the polar ice caps ever melt, as London, New York and numerous other major cities across the world would be submerged beneath the rising tides.
The harrowing future our environmentally-unfriendly behaviour is setting us up for has been visualised in all its worrying glory by National Geographic. With all the ice melted on the planet, London and New York would be joined by Amsterdam, Copenhagen, Venice, San Francisco, New Orleans and the whole of Florida in gaining new Atlantean status, with sea levels rising some 216 feet. The average global temperature would also rise, from 58 degrees Fahrenheit to a scorching 80.
Thankfully, it's unlikely to happen any time soon -- scientists estimate that it would take 5,000 years at current ice cap melting rates to hit this doomsday scenario. But if our reliance upon fossil fuels doesn't shift soon, even that distant date could creep much closer. [National Geographic]