In Poul Anderson's There Will Be Time (New York, 1973), the nuclear war puts so much dust into the atmosphere that the Bering Strait freezes. Asian Mong cross and conquer North American plains "...for their own herds and ranches." (p. 80) Feudal societies grow among American survivors. The Glacier Folk, hunters, trappers, raiders and traders in furs, hides, ores and slaves, later join the emergent North West Union.
In the Pacific, the Maurai Federation builds a new civilization with:
fleets of efficient sailing ships and electric-powered dirigibles;
solar energy screens charging accumulators;
bacterial fuel cells using organic wastes;
new scientific developments, especially biological;
a spreading biotechnological culture;
political domination of other developing countries;
suppression of nuclear power;
eventual violent resistance;
an incomprehensible successor civilization with a dichotomy between contemplation and high energy technology.
A Maurai philosopher advises Jack Havig:
"'...you, poor time wanderer, you must think beyond the next century. Come, this evening know peace. Observe the stars tread forth, inhale the incense, hear the songbird, feel the breeze, be one with Earth.'" (p. 126)