Sure, not too many though. Feel free to take a polar icecap one or make an australian one. (crikey amirite)

Oh, they need one because the earth has three biomes right now, in rough fractions: 3/4 FUCKING SAND JESUS ITS EVERYWHERE, 1/8th minor snowyness, and 1/8th Oasis. Nuclear war would do that to a planet, I think. Also, it's a big hovering train-battleship-tank! Who doesn't love those? 

Oh, and PM me about plot points you might be deviously devising about your own corporations. [s]Sorry but as GM I'm pretty sure I should assume direct control of all of the Ruling Companies.[/s]