904 resultados para Amazonia droughts


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It is analyzed, in this paper, the conflicts involving a family of small dairy cattle breeders, faced with the opposition of society and restrictions imposed by the local authorities, against the livestock grazing on public lands in peri-urban zone of a medium-sized Amazonian city. The case study employed participant observation, interviews and document research. Despite the subordinate position occupied by the focused group in the credibility hierarchy of versions issued on the conflict, the group maintains a resistance conduct, based both in the need for sustenance, and in an attempt to preserve a way of life cherished by its members

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El artículo analiza la organización social y la utilización de los recursos naturales por las familias beneficiadas por el programa de reforma agraria en la Amazonía brasileña, considerando aspectos de las prácticas recolectoras y del manejo comunitario de la floresta. El objeto de análisis es el Proyecto de Desarrollo Sustentable (PDS) Nova Bonal, ubicado en la provincia de Acre. La organización del territorio y de la producción en el PDS Nova Bonal al articular orientaciones direccionadas tanto para el atendimiento de las prácticas de agricultura convencional cuanto agro-recolectoras, tiene diferencias de otros asentamientos rurales creados por el gobierno brasileño. El trabajo analiza las posibilidades de esa modalidad de proyecto proporcionar el desarrollo socioeconómico de las familias beneficiadas y, al mismo tiempo, mejores condiciones de sustentabilidad en el uso de los recursos naturales. También son analizados los aspectos legales y formales que direccionan este modelo de proyecto de reforma agraria en el uso y manejo de los recursos naturales en la Amazonia.

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It is analyzed, in this paper, the conflicts involving a family of small dairy cattle breeders, faced with the opposition of society and restrictions imposed by the local authorities, against the livestock grazing on public lands in peri-urban zone of a medium-sized Amazonian city. The case study employed participant observation, interviews and document research. Despite the subordinate position occupied by the focused group in the credibility hierarchy of versions issued on the conflict, the group maintains a resistance conduct, based both in the need for sustenance, and in an attempt to preserve a way of life cherished by its members

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Las sequías se caracterizan por tener un comportamiento cíclico, lo que permite prever, en cierto modo, la probabilidad de su ocurrencia. Sin embargo, en el sudoeste bonaerense las medidas preventivas para mitigar sus efectos en la actividad agropecuaria son insuficientes. La Ley de Emergencia Agropecuaria (LEA) considera la sequía como un fenómeno puramente meteorológico, mientras que nuestro enfoque la aborda como producto de la vulnerabilidad social, consecuencia de una gestión deficiente y de la imprevisión por parte de los productores agropecuarios afectados. El recorte espacial de esta presentación abarca los partidos que conforman el Plan de Desarrollo del Sudoeste Bonaerense; y el temporal, el período 2001-2006, por la significativa ocurrencia de sequías. La sequía no necesariamente es un hecho catastrófico, sino que se da como una 'construcción social de riesgos' (García Acosta, 2005; Lavell, 2000), resultado de la falta de previsión y de la incertidumbre.

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It is analyzed, in this paper, the conflicts involving a family of small dairy cattle breeders, faced with the opposition of society and restrictions imposed by the local authorities, against the livestock grazing on public lands in peri-urban zone of a medium-sized Amazonian city. The case study employed participant observation, interviews and document research. Despite the subordinate position occupied by the focused group in the credibility hierarchy of versions issued on the conflict, the group maintains a resistance conduct, based both in the need for sustenance, and in an attempt to preserve a way of life cherished by its members

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El artículo analiza la organización social y la utilización de los recursos naturales por las familias beneficiadas por el programa de reforma agraria en la Amazonía brasileña, considerando aspectos de las prácticas recolectoras y del manejo comunitario de la floresta. El objeto de análisis es el Proyecto de Desarrollo Sustentable (PDS) Nova Bonal, ubicado en la provincia de Acre. La organización del territorio y de la producción en el PDS Nova Bonal al articular orientaciones direccionadas tanto para el atendimiento de las prácticas de agricultura convencional cuanto agro-recolectoras, tiene diferencias de otros asentamientos rurales creados por el gobierno brasileño. El trabajo analiza las posibilidades de esa modalidad de proyecto proporcionar el desarrollo socioeconómico de las familias beneficiadas y, al mismo tiempo, mejores condiciones de sustentabilidad en el uso de los recursos naturales. También son analizados los aspectos legales y formales que direccionan este modelo de proyecto de reforma agraria en el uso y manejo de los recursos naturales en la Amazonia.

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It is analyzed, in this paper, the conflicts involving a family of small dairy cattle breeders, faced with the opposition of society and restrictions imposed by the local authorities, against the livestock grazing on public lands in peri-urban zone of a medium-sized Amazonian city. The case study employed participant observation, interviews and document research. Despite the subordinate position occupied by the focused group in the credibility hierarchy of versions issued on the conflict, the group maintains a resistance conduct, based both in the need for sustenance, and in an attempt to preserve a way of life cherished by its members

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Las sequías se caracterizan por tener un comportamiento cíclico, lo que permite prever, en cierto modo, la probabilidad de su ocurrencia. Sin embargo, en el sudoeste bonaerense las medidas preventivas para mitigar sus efectos en la actividad agropecuaria son insuficientes. La Ley de Emergencia Agropecuaria (LEA) considera la sequía como un fenómeno puramente meteorológico, mientras que nuestro enfoque la aborda como producto de la vulnerabilidad social, consecuencia de una gestión deficiente y de la imprevisión por parte de los productores agropecuarios afectados. El recorte espacial de esta presentación abarca los partidos que conforman el Plan de Desarrollo del Sudoeste Bonaerense; y el temporal, el período 2001-2006, por la significativa ocurrencia de sequías. La sequía no necesariamente es un hecho catastrófico, sino que se da como una 'construcción social de riesgos' (García Acosta, 2005; Lavell, 2000), resultado de la falta de previsión y de la incertidumbre.

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El artículo analiza la organización social y la utilización de los recursos naturales por las familias beneficiadas por el programa de reforma agraria en la Amazonía brasileña, considerando aspectos de las prácticas recolectoras y del manejo comunitario de la floresta. El objeto de análisis es el Proyecto de Desarrollo Sustentable (PDS) Nova Bonal, ubicado en la provincia de Acre. La organización del territorio y de la producción en el PDS Nova Bonal al articular orientaciones direccionadas tanto para el atendimiento de las prácticas de agricultura convencional cuanto agro-recolectoras, tiene diferencias de otros asentamientos rurales creados por el gobierno brasileño. El trabajo analiza las posibilidades de esa modalidad de proyecto proporcionar el desarrollo socioeconómico de las familias beneficiadas y, al mismo tiempo, mejores condiciones de sustentabilidad en el uso de los recursos naturales. También son analizados los aspectos legales y formales que direccionan este modelo de proyecto de reforma agraria en el uso y manejo de los recursos naturales en la Amazonia.

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Explanations for the demise of the Classic Maya civilization on the Yucatán Peninsula during the Terminal Classic Period (TCP; CE 750-1050) are controversial. Multiyear droughts are one likely cause, but the role of the Caribbean Sea, the dominant moisture source for Mesoamerica, remains largely unknown. Here we present bimonthly resolved snapshots of reconstructed sea surface temperature (SST) and salinity (SSS) variability in the southern Caribbean from precisely dated fossil corals. Our fossil coral results from Bonaire indicate strong interannual to decadal SST and SSS variability in the southern Caribbean Sea during the TCP with multiyear extremes of high SSS and high SST that coincide with droughts on the Yucatán Peninsula. The results are best explained by changed Caribbean SST gradients affecting the Caribbean low-level atmospheric jet with consequences for Mesoamerican precipitation, possibly linked to changes in Atlantic Meridional Overturning Circulation strength. Our findings provide a new perspective on the anomalous hydrological changes on the Yucatán Peninsula during the TCP that complement the often-suggested southward displacement of the Intertropical Convergence Zone. We advocate for a strong role of ocean-atmosphere interactions in the Caribbean Sea related to the multiyear variations in Caribbean Sea surface conditions as an important driver of the spatially complex pattern of hydrological anomalies during the TCP.

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The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an important role in seasonal climate extremes such as hurricanes, floods and droughts at the present day, are not well known for this period that led into the last glacial. Here we present a monthly resolved snapshot of reconstructed sea surface temperature in the tropical North Atlantic Ocean for 117.7±0.8 kyr ago, using coral Sr/Ca and d18O records. We find that temperature seasonality was similar to today, which is consistent with the orbital insolation forcing. Our coral and climate model results suggest that temperature seasonality of the tropical surface ocean is controlled mainly by orbital insolation changes during interglacials.

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We present a suite of new high-resolution records (0-135 ka) representing pulses of aeolian, fluvial, and biogenic sedimentation along the Senegalese continental margin. A multiproxy approach based on rock magnetic, element, and color data was applied on three cores enclosing the present-day northern limit of the ITCZ. A strong episodic aeolian contribution driven by stronger winds and dry conditions and characterized by high hematite and goethite input was revealed north of 13°N. These millennial-scale dust fluxes are synchronous with North Atlantic Heinrich stadials. Fluvial clay input driven by the West African monsoon predominates at 12°N and varies at Dansgaard-Oeschger time scales while marine productivity is strongly enhanced during the African humid periods and marine isotope stage 5. From latitudinal signal variations, we deduce that the last glacial ITCZ summer position was located between core positions at 12°26' and 13°40'N. Furthermore, this work also shows that submillennial periods of aridity over northwest Africa occurred more frequently and farther south than previously thought.

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Millennial-scale dry events in the Northern Hemisphere monsoon regions during the last Glacial period are commonly attributed to southward shifts of the Intertropical Convergence Zone (ITCZ) associated with an intensification of the northeasterly (NE) trade wind system during intervals of reduced Atlantic meridional overturning circulation (AMOC). Through the use of high-resolution last deglaciation pollen records from the continental slope off Senegal, our data show that one of the longest and most extreme droughts in the western Sahel history, which occurred during the North Atlantic Heinrich Stadial 1 (HS1), displayed a succession of three major phases. These phases progressed from an interval of maximum pollen representation of Saharan elements between ~19 and 17.4 kyr BP indicating the onset of aridity and intensified NE trade winds, followed by a millennial interlude of reduced input of Saharan pollen and increased input of Sahelian pollen, to a final phase between ~16.2 and 15 kyr BP that was characterized by a second maximum of Saharan pollen abundances. This change in the pollen assemblage indicates a mid-HS1 interlude of NE trade wind relaxation, occurring between two distinct trade wind maxima, along with an intensified mid-tropospheric African Easterly Jet (AEJ) indicating a substantial change in West African atmospheric processes. The pollen data thus suggest that although the NE trades have weakened, the Sahel drought remained severe during this time interval. Therefore, a simple strengthening of trade winds and a southward shift of the West African monsoon trough alone cannot fully explain millennial-scale Sahel droughts during periods of AMOC weakening. Instead, we suggest that an intensification of the AEJ is needed to explain the persistence of the drought during HS1. Simulations with the Community Climate System Model indicate that an intensified AEJ during periods of reduced AMOC affected the North African climate by enhancing moisture divergence over the West African realm, thereby extending the Sahel drought for about 4000 years.

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Here we present evidence that the Holocene African monsoon system (AMS) varied in response to the eastern equatorial Atlantic sea-surface temperature (SST). Several short-term episodes of decreased moisture availability as a result of low eastern equatorial Atlantic SST are suggested by planktonic foraminiferal Mg/Ca ratios. These episodes promoted a weakening of the AMS and thus determined the timing and intensity of arid periods. Local sea-surface salinities also reveal regional patterns of precipitation in equatorial western Africa. The high eastern equatorial Atlantic SSTs occur in concert with seasonally increased insolation at low latitudes, suggesting a strong response of African monsoonal precipitation to oceanic conditions at low latitudes.

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Data compiled within the IMPENSO project. The Impact of ENSO on Sustainable Water Management and the Decision-Making Community at a Rainforest Margin in Indonesia (IMPENSO), http://www.gwdg.de/~impenso, was a German-Indonesian research project (2003-2007) that has studied the impact of ENSO (El Nino-Southern Oscillation) on the water resources and the agricultural production in the PALU RIVER watershed in Central Sulawesi. ENSO is a climate variability that causes serious droughts in Indonesia and other countries of South-East Asia. The last ENSO event occurred in 1997. As in other regions, many farmers in Central Sulawesi suffered from reduced crop yields and lost their livestock. A better prediction of ENSO and the development of coping strategies would help local communities mitigate the impact of ENSO on rural livelihoods and food security. The IMPENSO project deals with the impact of the climate variability ENSO (El Niño Southern Oscillation) on water resource management and the local communities in the Palu River watershed of Central Sulawesi, Indonesia. The project consists of three interrelated sub-projects, which study the local and regional manifestation of ENSO using the Regional Climate Models REMO and GESIMA (Sub-project A), quantify the impact of ENSO on the availability of water for agriculture and other uses, using the distributed hydrological model WaSiM-ETH (Sub-project B), and analyze the socio-economic impact and the policy implications of ENSO on the basis of a production function analysis, a household vulnerability analysis, and a linear programming model (Sub-project C). The models used in the three sub-projects will be integrated to simulate joint scenarios that are defined in collaboration with local stakeholders and are relevant for the design of coping strategies.