To become an immortal posthuman or something in line with that, that could be labeled as a (medium range) high tech of the future. But this is in a deep conflict with the Green vision which wants us to be born and to die like every other decent animal, until Mother Nature decides to wipe us all out.

Human immortality is uncomfortable to almost all non-transhumanists. Almost everyone has convinced themselves that getting hit with a baseball bat is a good thing (to use Eliezer's metaphor). This isn't specifically a Green problem. Greens might have some unique objections to immortality, such as fear of overpopulation, but they aren't uniquely opposed to immortality per se.