Publicações

Contemporary societies are being transformed by growing preoccupation with global environmental risks. The scientific basis for worries about human-induced climate change has consolidated, but many dimensions and implications remain uncertain and imprecise. In this area of what has been called post-normal science, facts are uncertain, values in dispute, stakes high, and decisions urgent. Plurality is its essence, and meaning-making fills gaps left by uncertainties. Actors – scientists, decision-makers, industry representatives, and members of environmental groups and the general public – variously clash and converge in their attempts to shape how societies understand the threat and what should be done about it. Among those favoring preventive action, some downplay or deny the uncertainties. Others – often with important leadership and financing by vested interests – exaggerate the uncertainties, or define them and the sociopolitical and economic implications of action to reduce carbon emissions in ways that undermine policy. Although everyone involved tends to focus on scientific arguments, choices of explanation by all the involved actors, and their very engagement in the debate, reveal political arrangements, moral commitments, and sociocultural ties as much as individual or group interests.

We used a climate-vegetation-natural fire (CVNF) conceptual model to evaluate the sensitivity and vulnerability of forest, savanna, and the forest-savanna transition to environmental changes in tropical South America. Initially, under current environmental conditions, CVNF model results suggested that, in the absence of fires, tropical forests would extend c. 200 km into the presently observed savanna domain. Environmental changes were then imposed upon the model in temperature, precipitation and lightning strikes. These changes ranged from 2 to 6 degrees C warming, +10 to -20% precipitation change and 0 to 15% increase in lightning frequency, which, in aggregate form, represent expected future climatic changes in response to global warming and deforestation. The most critical vegetation changes are projected to take place over the easternmost portions of the basin, with a widening of the forest-savanna transition. The transition width would increase from 150 to c. 300 km, with tree cover losses ranging from 20 to 85%. This means that c. 6% of the areas currently covered by forests could potentially turn into grass-dominated savanna landscapes. The mechanism driving tree cover reduction consists of the combination of less favorable climate conditions for trees and more fire activity. In addition, this sensitivity analysis predicts that the current dry shrubland vegetation of northeast Brazil could potentially turn into a bare soil landscape.

Irrigation with treated domestic sewage wastewater (TSE) is an agricultural practice to reduce water requirements of agroecossystems and the nutrient load impact on freshwaters, but adverse effects on soil chemical (salinization, sodification, etc.) and soil physical properties (alteration in soil porosity and hydraulic conductivity, etc.) have been reported. This study aimed to define some relationships among these changes in an Oxisol using multivariate analysis. Corn (Zea mays L.) and sunflower (Helianthus annuus L.) were grown for two years, irrigated with TSE. The following soil properties were determined: Ca2+; Mg2+; Na+; K+ and H + Al contents, cationic exchangeable capacity (CEC), sum of bases (SB), base saturation (V), texture (sand, silt and clay), macro-, micro-, and cryptoporosity (VMA, VMI and VCRI), water content at soil saturation (θS) and at field capacity (θFC), residual water content (θR), soil bulk density (ds), water dispersed clay (WDC) and saturated hydraulic conductivity (KSAT). Factor analysis revealed the following six principal factors: Fine Porosity (composed of Na+; K+; WDC, θR, θRFC, and VCRI); Large Porosity (θS, ds, VMA, Vs); Soil CEC (Ca2+; Mg2+; CEC, SB, V); Soil Acidity (H + Al); and Soil Texture (factors 5 and 6). A dual pore structure appears clearly to the factors 1 and 2, with an apparent relationship between fine porosity and the monovalent cations Na+ and K+. The irrigation (with potable sodic tap water or sewage wastewater) only had a significant effect on Fine Porosity and Large Porosity factors, while factors 3 and 4 (Soil CEC and Soil Acidity) were correlated with soil depth. The main conclusion was a shift in pore distribution (large to fine pores) during irrigation with TSE, which induces an increase of water storage and reduces the capacity of drainage of salts.

The Intergovernmental Panel on Climate Change (IPCC) projections for this century would certainly result in a suite of biophysical and socio-economic impacts on the Brazilian coastal zone that would ultimately affect several sectors, including natural ecosystems, fisheries, transportation, tourism and recreation, infrastructure and local communities.

Composições de 16 dias de índices de vegetação do sensor Moderate Resolution Imaging Spectroradiometer (MODIS), com resolução espacial de 250 metros, a bordo do satélite TERRA, foram utilizadas para caracterizar a dinâmica sazonal, no período de 2008, de duas fitofisionomias do bioma Mata Atlântica e analisar a sua dinâmica espectral. Os índices Normalized Difference Vegetation Index (NDVI) e Enhanced Vegetation Index (EVI), calculados a partir dos dados do sensor MODIS, e uma base comum de pixels, foram comparados entre si e com uma base de dados de ordem climática (temperatura e precipitação), para cada fitofisionomia. Os resultados indicaram que os fragmentos de floresta estacional decídua e floresta ombrófila mista apresentam um padrão sazonal comum, porém, com variações de amplitude em relação a cada índice. O EVI apresentou-se mais sensível às variações anuais da vegetação em relação ao NDVI, mostrando-se mais eficiente. Para ambas as formações florestais, se estabelece uma relação positiva entre o perfil EVI e NDVI com as variações de temperatura. A dinâmica espectral/temporal revelou um contraste marcante sob condições sazonais distintas, convergindo com o padrão apresentado pelos índices de vegetação. Os dados produzidos indicam potencialidades da utilização do sensor MODIS para o monitoramento contínuo das formações florestais de Mata Atlântica, com resolução espacial moderada e alta resolução temporal.

A modelagem numérica é uma importante ferramenta para a estimativa e previsão dos recursos de energia solar, imprescindíveis para o desenvolvimento, implementação e operação de projetos para aproveitamento dessa fonte energética limpa e de caráter renovável. O artigo apresenta o estudo realizado para desenvolvimento e adaptação de modelos empíricos para estimativa de irradiação solar em superfície em dois âmbitos: com abrangência local para localidades específicas e com abrangência regional para todo o território brasileiro. Os baixos desvios estatísticos entre as estimativas dos modelos e as medidas coletadas em superfície (RMSE de 17% a 23% para o modelo regional e de 15% a 26% para os modelos locais) mostraram a boa confiabilidade das estimativas fornecidas pelos mesmos. Adicionalmente, o desempenho de dois modelos clássicos da literatura (Ruth e Chant, 1976; Collares-Pereira e Rabl, 1979)foram comparados com o modelo local para São Martinho da Serra RS, verificando-se boa concordância entre suas estimativas, com exceção dos períodos de céu limpo (Kt > 0,7), nos quais o modelo local mostrou-se superior aos modelos clássicos.

A disponibilidade de dados hiperespectrais trouxe expectativas nos meios acadêmicos e empresariais quanto à potencialidade de sua aplicação no setor florestal. O objetivo deste trabalho foi avaliar a aplicação de dados hiperespectrais do sensor Hyperion EO-1 na caracterização espectral de plantios de Eucalyptus spp. e os efeitos da geometria de iluminação nesse processo. Para avaliar a geometria de iluminação foram utilizados dados topográficos provenientes do SRTM (Shuttle Radar Topography Mission) e as condições de iluminação presentes no momento da aquisição da imagem de satélite, gerando assim um fator de iluminação para a área de estudo. Os dados hiperespectrais foram convertidos para valores de FR de superfície, os quais passaram a constituir os dados fundamentais de todo o trabalho. A área de estudo contemplou os plantios do gênero Eucalyptus spp., pertencentes à empresa Fibria S.A., localizados no município de Capão Bonito (SP). Foram coletados dados de diferentes espécies e em diferentes etapas de desenvolvimento, o que caracteriza diferenças estruturais nos dosséis dos plantios. As componentes principais foram aplicadas nos dados e foram confeccionados gráficos dos fatores referentes às duas primeiras componentes, dos quais foram extraídas informações estruturais sobre os plantios.

Pyritic coal wastes produced by a coal beneficiation plant in the state of Santa Catarina in Southern Brazil are acid generating. Here we report the second part of a study evaluating the use of a dry cover to minimize acid mine drainage generation and its release into the environment. This part encompasses the construction and initial monitoring of an experimental pilot-scale unit. Local clays and ash from a power station were used as cover materials. Monitoring started in October 2007 and will extend for at least 4 years. Initial results of the dry cover system constructed using compacted locally available clay and ash look promising. The pH of the drainage ranged from 6.0 to 7.0, within the legal limits for discharge into the environment.

Countries considered in this section include: Brazil, east Bolivia, Paraguay, and north Argentina. La Niña-like conditions were present in early 2009, followed by the development of El Niño patterns starting in June 2009. During June September, sea surface temperatures were generally about 1°C warmer than the long-term average across the central and eastern equatorial Pacific. Considering the summertime mean of the 200009 decade for the tropical region east of the Andes, this decade showed less rainfall (about 200 mm below normal) as compared to 198090 (about 350 mm above than normal), while air temperatures were 0.5°C to 2°C warmer.

Countries considered in this section include: Brazil, east Bolivia, Paraguay, and north Argentina. La Niña-like conditions were present in early 2009, followed by the development of El Niño patterns starting in June 2009. During June September, sea surface temperatures were generally about 1°C warmer than the long-term average across the central and eastern equatorial Pacific. Considering the summertime mean of the 200009 decade for the tropical region east of the Andes, this decade showed less rainfall (about 200 mm below normal) as compared to 198090 (about 350 mm above than normal), while air temperatures were 0.5°C to 2°C warmer.

Os rios intermitentes do semiárido nordestino são apropriados para o teste de hipóteses ecológicas. Este artigo apresenta um estudo com isótopos de carbono e nitrogênio que mostrou que os animais aquáticos obtêm energia de fontes do próprio sistema, e não externas.

Portions of northern Uruguay, southern Brazil and northeastern Argentina experienced significant positive precipitation anomalies during November (fig. 7.15). Northern and western Uruguay, Rio Grande do Sul (state in Brazil), and Entre Rios (province in Argentina) felt the impacts of the flooding that affected all cities along the lower basin of Rio Uruguay River. Estimates indicated that more than 5000 people were evacuated from Uruguay alone. November 2009 was the wettest November in the last 30 years, since the Salto Grande dam was built (fig. 7.16). Overall, more than 350 mm of rain felt in the region between 25°S-35°S and 50°W-60°W. The monthly average is 150 mm, but in some places the record exceeded 600 mm. The National Institute of Meteorology of Brazil (INMET) and the National Institute for Space Research (INPE) reported that the November precipitation surpassed 400 mm at 19 meteorological stations of Rio Grande do Sul State, and average rainfall in all states was about 300 mm above normal. In Sao Luiz Gonzaga, the rainfall was 640 mm while the historical monthly average was 154 mm, a record for November since observations began in 1912.