Blue Mars

The red planet is red no longer, as Mars has become a perfectly inhabitable world. But while Mars flourishes, Earth is  threatened by overpopulation and ecological disaster. Soon people look to Mars as a refuge, initiating a possible interplanetary conflict, as well as political strife between the Reds, who wish to preserve the planet in its desert state, and the Green terraformers.  The ultimate fate of Earth, as well as the possibility of new explorations into the solar system, stand in the balance.
The electrifying finale to the most award-winning and bestselling SF trilogy to appear in years--the sequel to Red Mars and Green Mars. The colonists on Mars have nearly succeeded in transforming or terraforming the red planet to produce a liveable Earth-like atmosphere, when a new ice age imperils the Martian civilization.