(4) Rising ocean waters, scorching temperatures, food scarcity and disease – here’s how humans could ultimately be responsible for the end of the world.

Population growth has been so rapid that there is no real precedent we can turn to for clues about the possible consequences. In other words, while the planet might hold over 11 billion people by the end of the century, our current level of knowledge does not allow us to predict whether such a large population is sustainable, simply because it has never happened before. Credit: NOW THIS