I am now reading Blue Mars after having finished Green and Red Mars. The second book, Green Mars, started off slow, ending with a long awaited and eventful climax. The last book, Blue Mars, continues the pace of the previous book's final chapters with a positive tone.
Putting aside the science fiction, the books basically speak of hope, the possibility of creating a new and better society out of the old. Tempered idealism essentially drives the story, and the ideas come from many places: astronomy, geology, robotics, climatology, ecology, genetics, psychology, sociology, religion, politics, planning, engineering, architecture, etc. I guess all the author needed was just the right situation to allow all the ideas to come together, and the first place that came to mind just so happened to be the fourth planet from the sun, Mars.
I wonder if we can find a similar place closer to home.