Cordes Junction, Ariz. --- In the high desert of central Arizona, more than five thousand miles from the global-warming summit in Copenhagen, sits an aging and unfinished vision of the enviro-friendly, sustainable life that some climate change activists foresee for us all. It's called Arcosanti, created in 1970 by the Italian architect Paolo Soleri, and it is the prototype of a green community of the future. The only problem is, it doesn't work. And it never did. Arcosanti is an "arcology," a word Soleri coined by combining "architecture" and "ecology." In Soleri's vision, an arcology is a self-contained city in...