The warnings were all there but we chose not to listen. In the end, corporate greed won out and our planet paid the price. The polar ice caps melted, moving beach-front properties several hundred miles inland, and solar radiation microwaved anything left on land. The brightest and wealthiest were able to escape to the Lunar Colonies and the Orbital Space Station. The rest were forced below the surface. Some burrowed ever deeper underground while the rest were taken in by the merfolk.