Use este identificador para citar ou linkar para este item:
Título: Toward's a water balance in Central Amazon.
Autor(es): P.R. Leopoldo
E. Salati
M. de N.G. Ribeiro
Wolfram Karl Franken
Assunto: ciclo das aguas / floresta tropical
Revista: Experiencia
Volume: 43 (3)
Resumo: The possible effect of the Amazonian forest ecosystem on the regional, or even on the global, climate, is a subject discussed with much polemical ado. Until the 1960s the Amazonianforest cover remained essentially intact 4. However, with the construction of roads in the 70s colonization, accompanied by defor- estation, set in with ever-increasing speed. Under the auspices of the 'Instituto Nacional de Coloniza~fio e Reforma Agrfiria', the government alone removes an av- erage of 25,000 km 2 of forest per year s~ As a result of this process, national and international concern has intensified. In the absence of hard scientific data, and nurtured by conjecture and hypotheses only, the discussion has acquired a rather unrealistic and per-haps even polemical tenor, and contradictory views are defended with equal conviction. Thus, some authors claim that the energy liberated by the condensation of water vapors from the Amazon Basin, which is transported in the higher atmospheric strata to the polar regions, represents an important contribution to the thermal equilibrium of the earth 35. If this were proven to be true, the deforestation of this region would result in a higher temperature contrast between polar and more central latitudes of the globe. Others hypothesize that even complete deforestation would have little global impact. Sellers 47 estimates that the effect would merely be a reduction of the annual rainfall in Amazonia by 250 mm, and, on the other hand, the arid Brazilian Northeast would benefit from in- creased precipitation. Conclusions of global irrelevance have also issued from the Centre for Informatics, God- dard Institute, New York, which is considered to be one of the most sophisticated agencies for simulation prog- nostication. In this model, the climatological parameters of the forest, such as surface temperature, evapo- transpiration, light reflection, etc. were replaced by the respective values for tropical pastures. The modeP ~, how- ever, omits important factors such as the release of CO2 by the burning of the forest; this is one of the major preoccupations of climatologists, because it mightlead to higher global temperatures and thus could even cause partial melting of the polar ice caps 47. As for regional effects, the Goddard futurologists admit that pastures would retain less rainwater and that, therefore, erosion would intensify and cause an equivalent increase of sedi- ments in rivers, and that this, in turn, could endanger the plankton and the entire aquatic fauna 5~. Fortunately, though, matters have moved beyond mere conjecture and dispute. National and international agen- cies have cooperated in setting up a number of research programs on the interaction between vegetation and at- mosphere throughout the northern Brazilian states and through the Amazon Basin as a whole, including the eighboring countries (fig. 1). For example, the Instituto Nacional de Pesquisas da Amaz6nia (INPA), the Centro de Energia Nuclear na Agricultura (CENA), the Instituto Nacional de Pesquisas Espaciais (INPE),ORSTOM (France), the American States Organization (OEA), the International AtomicEnergy Agency (IAEA), and the IVIC (Venezuela-San Carlos), are only a few of them. Some results of the OEA-project, at Model Basin, are summarized by Walker and Franken 53. However, in view of the enormous problems, that would arise from a possible destabilization of the Amazonian ecosystem, these efforts must be considered as a modest beginning and as an incentive for continued research.
Local de publicação: Brasil
Aparece nas coleções:Coordenação de Dinâmica Ambiental (CDAM)

Arquivos associados a este item:
Arquivo Descrição TamanhoFormato 
towards_a_water.pdf1,12 MBAdobe PDFVisualizar/Abrir

Este item está licenciada sob uma Licença Creative Commons Creative Commons