Seeing how many people here would be flooded by rising sea levels made me wonder about the population distribution by elevation. I found this figure
Now I have to wonder why civilization is so clustered at low altitudes. There are certainly historical reasons for it. In the past, cities sprung up and grew the most where trade was concentrated, i.e. where ships could come to shore to offload goods. I suppose water may be more plentiful at lower elevations as well, enabling more food production. Now, though, with modern shipping people can live just about anywhere and get the things they need, so those issues shouldn't be significant factors anymore. Are people now living at those altitudes primarily because that's where the cities are?