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1.
Sci Rep ; 14(1): 5131, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38429332

RESUMO

Land use change and atmospheric composition, two drivers of climate change, can interact to affect both local and remote climate regimes. Previous works have considered the effects of greenhouse gas buildup in the atmosphere and the effects of Amazon deforestation in atmospheric general circulation models. In this study, we investigate the impacts of the Brazilian Amazon savannization and global warming in a fully coupled ocean-land-sea ice-atmosphere model simulation. We find that both savannization and global warming individually lengthen the dry season and reduce annual rainfall over large tracts of South America. The combined effects of land use change and global warming resulted in a mean annual rainfall reduction of 44% and a dry season length increase of 69%, when averaged over the Amazon basin, relative to the control run. Modulation of inland moisture transport due to savannization shows the largest signal to explain the rainfall reduction and increase in dry season length over the Amazon and Central-West. The combined effects of savannization and global warming resulted in maximum daily temperature anomalies, reaching values of up to 14 °C above the current climatic conditions over the Amazon. Also, as a consequence of both climate drivers, both soil moisture and surface runoff decrease over most of the country, suggesting cascading negative future impacts on both agriculture production and hydroelectricity generation.

2.
PLoS One ; 12(2): e0172330, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28222159

RESUMO

BACKGROUND: This study aims to describe the role of mobility in malaria transmission by discussing recent changes in population movements in the Brazilian Amazon and developing a flow map of disease transmission in this region. METHODOLOGY/PRINCIPAL FINDINGS: This study presents a descriptive analysis using an ecological approach on regional and local scales. The study location was the municipality of Porto Velho, which is the capital of Rondônia state, Brazil. Our dataset was obtained from the official health database, the population census and an environmental database. During 2000-2007 and 2007-2010, the Porto Velho municipality had an annual population growth of 1.42% and 5.07%, respectively. This population growth can be attributed to migration, which was driven by the construction of the Madeira River hydroelectric complex. From 2010 to 2012, 63,899 malaria-positive slides were reported for residents of Porto Velho municipality; 92% of the identified samples were autochthonous, and 8% were allochthonous. The flow map of patients' movements between residential areas and areas of suspected infection showed two patterns of malaria transmission: 1) commuting between residential areas and the Jirau hydropower dam reservoir, and 2) movements between urban areas and farms and resorts in rural areas. It was also observed that areas with greater occurrences of malaria were characterized by a low rate of deforestation. CONCLUSIONS: The Porto Velho municipality exhibits high malaria endemicity and plays an important role in disseminating the parasite to other municipalities in the Amazon and even to non-endemic areas of the country. Migration remains an important factor for the occurrence of malaria. However, due to recent changes in human occupation of the Brazilian Amazon, characterized by intense expansion of transportation networks, commuting has also become an important factor in malaria transmission. The magnitude of this change necessitates a new model to explain malaria transmission in the Brazilian Amazon.


Assuntos
Doenças Endêmicas , Malária/transmissão , Dinâmica Populacional , Animais , Brasil/epidemiologia , Cidades , Conservação dos Recursos Naturais , Geografia Médica , Humanos , Malária/epidemiologia , Ocupações , Centrais Elétricas , População Rural , Migrantes , Meios de Transporte , População Urbana
3.
Glob Chang Biol ; 22(5): 1821-40, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26511401

RESUMO

Following an intense occupation process that was initiated in the 1960s, deforestation rates in the Brazilian Amazon have decreased significantly since 2004, stabilizing around 6000 km(2) yr(-1) in the last 5 years. A convergence of conditions contributed to this, including the creation of protected areas, the use of effective monitoring systems, and credit restriction mechanisms. Nevertheless, other threats remain, including the rapidly expanding global markets for agricultural commodities, large-scale transportation and energy infrastructure projects, and weak institutions. We propose three updated qualitative and quantitative land-use scenarios for the Brazilian Amazon, including a normative 'Sustainability' scenario in which we envision major socio-economic, institutional, and environmental achievements in the region. We developed an innovative spatially explicit modelling approach capable of representing alternative pathways of the clear-cut deforestation, secondary vegetation dynamics, and the old-growth forest degradation. We use the computational models to estimate net deforestation-driven carbon emissions for the different scenarios. The region would become a sink of carbon after 2020 in a scenario of residual deforestation (~1000 km(2) yr(-1)) and a change in the current dynamics of the secondary vegetation - in a forest transition scenario. However, our results also show that the continuation of the current situation of relatively low deforestation rates and short life cycle of the secondary vegetation would maintain the region as a source of CO2 - even if a large portion of the deforested area is covered by secondary vegetation. In relation to the old-growth forest degradation process, we estimated average gross emission corresponding to 47% of the clear-cut deforestation from 2007 to 2013 (using the DEGRAD system data), although the aggregate effects of the postdisturbance regeneration can partially offset these emissions. Both processes (secondary vegetation and forest degradation) need to be better understood as they potentially will play a decisive role in the future regional carbon balance.


Assuntos
Poluentes Atmosféricos/análise , Carbono/análise , Conservação dos Recursos Naturais , Florestas , Brasil , Simulação por Computador , Monitoramento Ambiental
4.
Biota neotrop. (Online, Ed. port.) ; 10(4): 323-330, Oct.-Dec. 2010. graf, tab
Artigo em Português | LILACS | ID: lil-578510

RESUMO

Este artigo mostra através da análise de dados censitários sobre uso da terra no Brasil que a possível dicotomia entre a preservação da vegetação natural e a produção de alimentos na realidade não existe. Demonstramos que o Brasil já tem uma área desprovida de vegetação natural suficientemente grande para acomodar a expansão da produção agrícola. Demonstramos também que a maior expansão se dá nas áreas ocupadas pelas chamadas culturas de exportação - soja e cana-de-açúcar - e não propriamente nas áreas ocupadas por arroz, feijão e mandioca, que são consumidos de forma direta pelo mercado nacional. Pelo contrário, a área colhida de arroz e feijão tem inclusive decrescido nas últimas décadas, enquanto a área colhida de mandioca encontra-se praticamente constante há quatro décadas. Os maiores entraves para a produção de alimentos no Brasil não se devem a restrições supostamente impostas pelo Código Florestal, mas, sim, à enorme desigualdade na distribuição de terras, a restrição de crédito agrícola ao agricultor que produz alimentos de consumo direto, a falta de assistência técnica que o ajude a aumentar a sua produtividade, a falta de investimentos em infraestrutura para armazenamento e escoamento da produção agrícola, a restrições de financiamento e priorização do desenvolvimento e tecnologia que permita um aumento expressivo na lotação de nossas pastagens,.


Through the analysis of census data on land use in Brazil this article shows that the dichotomy between food production and preservation of natural vegetation used as the main driver to change the Forest Code is false. We showed here that Brazil has already cleared an area large enough that support the production of food, fiber and bioenergy to meet the requirements of the country and global markets. We also showed the area of export-oriented crops like soybean and sugar cane have been expanded significantly in the last decades, while staple crops like rice and bean have decreased and the area planted with cassava has been stable for the last four decades. At the same time we show that the productivity of export-oriented crops has increased in a much more significant rate than staple crops or cattle stocking rate, which in average is extremely low in Brazil. We concluded by stating that the real constraint for food production in Brazil does not rely on the Forest Code environmental restrictions but instead in inequalities in land distribution and income, coupled with lack of credit to small producers and investment in research and development in the staples crops of the country.

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