I am an environmentalist, specifically a follower of the "bright green" ideas. Bright greens are not techno-utopians, but we lean in that direction. Bright green is basically the opposite of the "Dark green" back to nature ideas. Going "back to nature" would solve many environmental issue, but that preindustrial lifestyle would support only a much smaller population (world population did not reach 1 billion until ~1830). Further, even if everyone agreed to that lifestyle and we ignore the death toll, each generation would be tempted to advance technology again. Another common green approach is to just be a little better. Put some regulation on pollutants, recycle a little, don't litter, use CFLs. This is tempting because it seem relatively easy.
But there are no easy solutions to our environmental problems. Many don't seem to realize the magnitude of what must be done. We must undergo an all-encompassing, huge shift in our economy, our habits, and in the very fabric of our lives. The change is as big as the Industrial Revolution. Just as our lives have little resemblance to the lives of pre-industrial people, so post-Green Revolution lives will not much resemble our current lifestyle. The good news, though, is that we don't give up modern technology, modern medicine, or even many modern comforts. Bright green living also has many goals and results that parallel social justice.
(more to come)