-Carbon sequestration in wood products in Portugal was estimated for the 1990-2000 period using two accounting approaches: the stock-change and the atmospheric-flow. Calculations rely on historical data for production and trade of wood products, and on typical values for their lifetimes. Carbon sequestration in wood products, calculated by the stock-change approach, increased from 310 Gg C yr -1 in 1990 to 611 Gg C yr -1 in 2000. The estimates of carbon sequestration using the atmospheric-flow approach, in the same period, varied from 322 Gg C yr -1 to 783 Gg C yr -1 , and do not show the same increasing trend given by the stock-change approach, as they depend not only on the change in the stocks of wood products but also on their trade. The sensitivity analysis performed shows that the results are significantly affected by the parameters related with the lifetime of the products, the carbon fraction in paper and the biomass conversion factor. carbon sequestration / wood products / stock-change approach / atmospheric-flow approach / Portugal Résumé -Contribution des produits du bois à la séquestration du carbone au Portugal. La séquestration de carbone par les produits du bois au Portugal a été estimée pour la période 1990-2000, par deux approches de calcul: le stock-change et l'atmospheric-flow. Les calculs se basent sur des données historiques de production et de commerce de produits du bois, ainsi que sur les durées de vie caractéristiques de ces produits. La séquestration de carbone par les produits du bois, calculée par l'approche stock-change, a augmenté de 310 Gg C an -1 à 611 Gg C an -1 entre 1990 et 2000. La séquestration de carbone, estimée par l'approche atmospheric flow, pour la même période, a varié entre 322 Gg C an -1 à 783 Gg C an -1 , et ne présente pas la même tendance d'augmentation obtenue par l'approche stock-change, vu qu'elle dépend non seulement de la variation des stocks des produits du bois, mais aussi du commerce des produits du bois. Une analyse de sensitivité réalisée montre que les résultats sont significativement affectés par les paramètres liés à la durée de vie des produits, la fraction de carbone dans le papier et le facteur de conversion de la biomasse. séquestration de carbone / produits du bois / stock-change approach / atmospheric-flow approach / Portugal
The potential environmental burdens over the whole life cycle of printing and writing paper produced in Portugal from Eucalyptus globulus were quantified, using Life Cycle Assessment (LCA) methodology. The main stages considered in the life cycle were: forest, pulp production, paper production, final disposal, energy production, chemical production and transports. The results suggest that pulp production processes have an important contribution to water emissions, resulting in a major contribution to eutrophication. Besides, it plays a major role in renewable energy consumption. Energy production in the grid, printing and writing paper production and transports contribute significantly to air emissions and to non-renewable energy consumption, and, consequently to global warming, acidification and non-renewable resource depletion. Wastepaper landfilling assumes the predominant role in photochemical oxidant formation.
Through a historical description of the human occupation of Lisbon since the twelfth century BC and its reorganization around the natural presence of the estuary of the river Tagus, this chapter explores concepts like tourism, naturalization, and city. In this sense, the chapter made a critical perspective on the changes occurred in the last years, discussing the contemporary contingency of competitiveness and urban places transformation related to sustainability and tourism pressure in the revaluation of centralities. This can be considered an awareness of the need to reflect on a kind of search for the loss of its authenticity.
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