sustainable development 20 years on from the ... - José Eli da Veiga

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Box I.7
URBAN SUSTAINABILITY IN SIX METROPOLITAN CITIES IN LATIN AMERICA
AND THE CARIBBEAN
At present, one fifth of urban residents in the region live in metropolitan cities, that is cities with five million or
more inhabitants. An overview of six of these cities in Latin America and the Caribbean, namely Mexico City, São
Paulo, Buenos Aires, Lima, Santiago and Bogota, reveal the following advances and challenges in terms of urban
sustainability.
(a)
Water consumption, pollution and treatment
Between 1996 and <strong>20</strong>05, Bogota cut water consumption by nearly <strong>20</strong>%, thanks to such factors as tighter
controls on water use, steep price increases, a new law on rational water use and the impact of the 1997 economic
crisis. São Paulo, meanwhile, has reported that water losses have been reduced as a result of the renovation of
infrastructure and tighter controls on illicit water use. Santiago, Chile, has a much higher installed capacity and
much more extensive wastewater treatment coverage than the other cities. In Lima, nearly 30% of the drinking water
supply is lost, and the ratio of potable water hook-ups is the lowest of all of these cities. Buenos Aires and Bogota
have high pollution levels due, primarily, to the volume of untreated household wastewater. All six of these cities
have high biological pollution indices for their watercourses. Mexico City dumps most of its wastewater without
running it through even primary treatment processes.
(b)
Electric power and electricity use
Bogota, Lima and Mexico City have high carbon-efficiency levels per dollar of GDP. The mass transit
systems of Santiago, Buenos Aires and Bogota are the most energy-efficient. Mexico City has the most energyefficient
economic system, while the coefficients for the rest of the cities are fairly similar (between US$ 0.30 and
US$ 0.40 per kWh). Buenos Aires, São Paulo and Santiago have extremely high levels of carbon emissions per
dollar of GDP. Residential and total electricity use is highest in Santiago, São Paulo, Buenos Aires and Bogota,
while use rates are considerably lower for Lima and Mexico City.
(c)
Solid waste management
In Santiago, Chile, about 50% of landfills gases are flared. Waste management in these six cities is in large
part outsourced by municipalities to private companies. Informal garbage collection is a major factor in Bogota,
Mexico City and Lima, but in all six mega-cities, a great deal of garbage is left uncollected and has a direct impact
in terms of water, soil and air pollution. Formal recycling systems in these cities are poorly developed, and are not
being used to their full potential. Greenhouse gas emissions, especially of methane, are highest in Mexico City and
São Paulo. Systems for the appropriate management, disposal and recycling of solid wastes are not yet being
successfully implemented in many cities of the region.
(d)
Air pollution and greenhouse gas emissions
Automobile traffic and industry are the mains sources of air pollution. Because Mexico City and São Paulo
are so much larger, their carbon monoxide emissions are about 10 times greater than the level for Santiago. As of
<strong>20</strong>05, standards for sulphur concentrations in diesel fuels were quite different in these six cities. In Lima, for
example, the ceiling was 3,000 ppm, while Santiago had the most rigorous standard (50 ppm). The aim for <strong>20</strong>10
was for all six of these cities to introduce legal ceilings of between 15 and 50 ppm, but this target has not been
met in all cases. Extremely high levels of air pollution are undermining the health of the population, and the
economic cost of combustion-engine vehicles is not reflecting their actual costs. The growing use of automobiles,
unsuitable land-use patterns, lax regulations, weak enforcement and an inadequate pricing system are some of the
main contributing factors.
Source: Ricardo Jordán, Johannes Rehner and Joseluis Samaniego, “Regional panorama Latin America: megacities and
sustainability”, Project documents, No. 289 (LC/W.289), Santiago, Chile, Economic Commission for Latin America
and the Caribbean (ECLAC)/German Agency for International Cooperation (GTZ), <strong>20</strong>10.