GreenHorns Showdown in Smart World by Richard C. Wagner

Crusty Texan Cactus "Rip" Hays, the prized prisoner of the environmental utopia of Smart World, secretly plots a revolt against his captors. His enemies, the Lords of Smart World and terrorists who reside within the walls of Smart World's super-skyscrapers, came to power in the Green Revolution in the early 21st century. The only souls to have escaped confinement in the super-skyscrapers are Hays' fellow Texans, a few thousand hardy and fierce rebels who dwell in freedom in the Great Wilderness and vow to retake their land seized by the greenhorns.