The Gaian Expedient

Time had run out for the twentieth century, and civilization disappeared in radioactivity, heat, and fire. But farsighted men had hidden a colony to help Man recover from the War—and, perhaps, even prevent future ones. Yet after several hundred years, time was running out for the colony as well—Yggdrasil's supplies were almost gone, the tribes she was to teach refused to learn, and nomads daily raided her borders. And as shortages became more desperate, radical solutions were proposed by those who had lost sight of Yggdrasil's goals. If something wasn't done soon, Yggdrasil would be reduced to using the same methods that had previously threatened the planet...