|The Mega-city in Latin America (UNU, 1996, 282 pages)|
|2 Demographic trends in Latin America's metropolises, 1950-1990|
Most urban planners in Latin America have long been concerned at the way metropolitan areas have spread outwards in apparently uncontrolled and explosive ways. The suburbs have spread like ink across blotting paper. In the process they have left enormous swathes of unused land within the urban perimeter and created vast low-income settlements with poor links to the rest of the metropolis (see chapter 4). This tendency has accentuated the problems of these cities, increasing transport problems, weakening infrastructure systems further, and putting impossible demands on local authorities with limited financial resources (Bähr and Mertins, 1993; CED, 1990; PREALC, 1990; Tulchin, 1993). Uncontrolled urban expansion has also led to the occupation of land quite unsuited to dense urban settlement. Major problems now face the settlers of low-income settlements located on land liable to flood, particularly in parts of Buenos Aires, Santiago, and São Paulo, and on steep hillsides subject to slippage, particularly in cities such as Caracas and Rio de Janeiro (Fadda, 1992; Ibarra et al. (eds.), 1986a; UNCRD, 1994).
Rapid metropolitan growth has caused additional problems when it has occupied fertile agricultural land. This has been a major headache in Bogotá, where the city is located at the edge of a large plain producing much of Colombia's wheat, potato, and barley and the bulk of its flower exports (Rode, 1992). In Lima, where the urban area increased thirty times between 1940 and 1993, the Province of Lima has lost three-quarters of its agricultural land (de Llona, 1991; Muñoz, 1991).
As the cities have expanded outwards, population growth in the central areas has slowed down. Few of the old administrative centres of the megacities have grown much in recent years, and in the case of the Federal District of Mexico, its population actually declined by 600,000 people between 1980 and 1990. This tendency has been particularly marked in the oldest parts of the cities since around 1970 (see chapter 4). The populations of central Buenos Aires, Caracas, Lima, and Mexico City are now in decline, and in Santiago there is public concern about the "depopulation of the historic core of the city" (CED, 1990; Rodríguez, 1993). Only the two Brazilian mega-cities seem to have escaped this trend: a result of new skyscraper developments and the development of increasing numbers of low-income tenements.
Since the 1970s, and in accentuated form during the 1980s, metropolitan expansion has taken a very different form from that in the past. Much of the growth is no longer within the urban perimeter. It has shifted to a number of towns and secondary cities within the wider metropolitan region but some distance from the main urban centre. This process has been one sign of the "polarization reversal" discussed earlier and is a first step in the creation of conurbations like those of Europe, the United States, and Japan.
As transport and communication networks have improved, and as infrastructural provision has been extended to secondary centres, companies have been able to operate successfully beyond the confines of the region's principal city. The process is not new in Latin America but it has recently intensified (Garza, 1978; Sabatini, 1991). The economic hinterland of Mexico City, which has gradually embraced Cuernavaca, Pachuca, and Toluca, now extends as far as Puebla and Querétaro, 128 and 224 km respectively by motorway from the capital (CONAPO, 1992) (see chapter 8). In Brazil, São Paulo's hinterland now embraces Campinas, Cubatão, Santos and São Jose dos Campos. A discontinuous economic and urban complex now spreads hundreds of kilometres from the centre of São Paulo (Cano and Pacheco, 1991; de Mattos, 1992a; Kowarick and Jacobi, 1986; UN, 1993c; see also chapters 4 and 10). In Venezuela, a similar kind of process has been emerging for a number of years, with a chain of cities, including La Victoria, Maracay, and Valencia, spreading westwards from Caracas along the motorway to Puerto Cabello.
The tendency towards "concentrated deconcentration" has sometimes been encouraged by the state. In Argentina, the state has encouraged industrial companies to move to the outskirts of Greater Buenos Aires (Pesci and Ibañez, 1992). In Chile, there are plans to stimulate development in a wide area around Santiago, which include some population relocation and major improvements to the transportation system. The area concerned stretches 160 km to the west, 96 km to the north and 240 km to the south (Echeñique, 1992; Necochea, 1991; Sabatini, 1991).
Manufacturing industry has been the prime mover in this trend towards urban deconcentration and other sectors have lagged behind; indeed, tertiary activity has sometimes moved in the opposite direction, becoming more concentrated in the principal city. As manufacturing has moved out, however, the figures suggest that mega-cities have lost some of their national importance in this sector. Such figures are misleading in that, while the principal city often has a lower share of manufacturing employment and value added, its wider region has often strengthened its hold.
Only rarely has this trend been fully reflected in terms of the distribution of people. In Brazil, the area around São Paulo has grown more slowly than urban areas generally, the combined population share falling from 21 per cent of the state's population to 19 per cent between 1980 and 1991. Similarly, in Chile, the Santiago macro-region has grown more slowly than the nation's urban population. In the case of Mexico, the main metropolitan region has lost out even more dramatically, the combined urban population of the area between Mexico City, Puebla-Tlaxcala, Toluca, and Cuernavaca falling from 36 per cent in 1970 to 32 per cent in 1990 (Ruiz, 1993).