AVALIAÇÃO DA SUSTENTABILIDADE BIOFÍSICA DO SOCIOECOSSISTEMA SÃO LUIS, ATRAVÉS DO ÍNDICE PEGADA ECOLÓGICA.

Abstract

The 7,4 billion hectares of lands ecologically productive available for human use are decreasing in an abrupt way, since last century and, more intensely, in the last decades, mainly due to the significant increase of the world human population and the consumption produced by that. From this fact, the concept of sustainability began to be part of the scientific economic, social and political world agendas. Indicators and indexes of environmental sustainability were created with the objective of measuring the production and the consumption of the essential natural elements to life, to follow the loss/degradation levels to minimize, to replace or to optimize their use. The Ecological Footprint it is one of those sustainability indexes created in 1996, recognized as analytic and educational, that measures how much of the land and sea areas are necessary to reach the consumption of products and services of a population, of a process or of an individual. The results are compared with the available bioproductive area and expressed in balance terms or ecological deficit. The cities are recognized as playing a decisive part in the development of the civilization as something between 58 and 61% of the world population live in cities. São Luís is included in the dynamic and historical processes that happened in Brazil and in the world, with an average annual growth higher than Brazil´s and the Northeast region in the period of 1991-2000. The major objective of this study is to calculate the Ecological Footprint Index of the municipal district of São Luís in the years 2000 and 2004, evaluating the biophysical sustainability of that urban socio-ecosystem through the analysis of the consumption of fuel, water, electricity, food, wood, emissions of CO2, green house effect gas, and the productive natural areas necessary to sustain and to assimilate the generated solid residues. Moreover, to compare the result obtained with the one of other municipal districts of Brazil where this index was already established, to estimate the municipal contribution to the global environmental changes and to contribute to improve the planning, management and the generation of policies. Additionally, the analysis of CO2 captured by a water body (Bacanga) was made and the index of environmental preservation of the area was calculated. As the result, São Luís showed an ecological deficit, and needs an area about 20 times larger than the available to maintain its activities. The element that more contributed to that result was the fuel consumption and the one that less influenced was the water. Only as the consequence of fuel consumption, about 2.087.179.546 tons of CO2 were emitted to the atmosphere in the years of the study. Therefore, facing the population growth that causes decrease of the areas of environmental protection that provide ecological services of life maintenance, it is necessary that public decision makers and each São Luis citizen, review their consumption habits, look for the use of ecologically correct technologies and the conservation of the ecosystems.