The Greens were a somewhat diverse international political group on Earth during the beginning of the Diaspora who used environmental restoration as their guiding principle.
Most came from more developed areas and nations. Along with the Neo-Luddites, they formed a coalition which rose to power around 50 PD which would transform the old United Nations into the Earth Union. This coalition would remain in power until the Economic Winter of 252 PD. Although generally techno-illiterate, only the most extreme Greens were actually technophobes. (HHA6.1: BTB)
By the early 4th Century PD, the Greens had become increasingly irrevelant, their more extreme members being considered "crackpots". These extremists in no way distinguished between colonization and other space activity, wanting man to live the way they were "supposed to" without artificial technological aids. (HH2)