THE GLOBAL CITY

Four main forces appear to be shaping urban growth and change at the e nd of the twentieth century: tertiarization, the shift from manufactur ing to services; informationalization, the increasing use of informati on as the basis of the economy; the resulting locational disarticulati on whereby command-and-control functions are carried out in places dif ferent from production locations; and constant innovation in both manu facturing and, increasingly, the generation and exchange of informatio n. The result is a new urban hierarchy dominated by a few global citie s. Their worldwide distribution depends a great deal on historical acc ident; there are fundamental and deep-seated differences between the u rban hierarchies of North America, Europe, and Japan. But in all, high er-level urban development is concentrated into quite small axial belt s: Boston-NewYork-Philadelphia-Baltimore-Washington, the Tokaido corri dor of Japan, and the complex pattern of transport corridors connectin g the major cities of North-West Europe. While on the macro scale ther e is increasing concentration into metropolitan areas and corridors, a t the level of the individual metro area there is simultaneous dispers al of homes and jobs, which further increases journeys and poses chall enges to sustainable urban development. Cities are just beginning to d evelop strategies to meet the resulting tension.