Sea level rise will hit the coasts the hardest. Over the coming centuries, land that is today home to between 470 and 760 million coastal residents will be inundated by sea level rise associated with a 4 degree Celsius warming that will occur if we fail to curb the amount of carbon dioxide in the atmosphere. Much of this population lives in cities. Sea level rise already makes storms more dangerous, causing more flooding and damage in areas crowded with people. And it will affect different parts of the world differently, with some parts of the planet being particularly hard hit.