Europa was terraformed in the 21st century. It is mostly a desert with the landscape littered with "Land for Sale" signs. Inside walled cities on Europa, temperate climates are artificially produced. The walls of the cities actually keep the climate within the cities themselves sort of like a giant refrigerator, except the inside is warm and the air is not arid. It seems that the reason that this moon is mostly desert is because it's in the early stages of being terraformed.
Europa was part of some trucking lines.