"The Barren Earth" from Conqueror of the Barren Earth #3 (DC, 1985) by Gary Cohn and Ron Randall
The only time I bought Warlord was to support the Barren Earth back-up, which had a smokin' hot lead and an interesting techno-fantasy world to explore. The story ended in the pages of a 4-issue mini-series, and the whole thing was well outside the DC Universe. Can't the New52 work it back in? Or does Earth HAVE to survive as a civilized place for century upon century?