Critical transitions in the Amazon forest system.

The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern1-3. For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, the region is increasingly exposed to unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central and remote parts of the system1. Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition. Here we analyse existing evidence for five major drivers of water stress on Amazonian forests, as well as potential critical thresholds of those drivers that, if crossed, could trigger local, regional or even biome-wide forest collapse. By combining spatial information on various disturbances, we estimate that by 2050, 10% to 47% of Amazonian forests will be exposed to compounding disturbances that may trigger unexpected ecosystem transitions and potentially exacerbate regional climate change. Using examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories, involving different feedbacks and environmental conditions. We discuss how the inherent complexity of the Amazon adds uncertainty about future dynamics, but also reveals opportunities for action. Keeping the Amazon forest resilient in the Anthropocene will depend on a combination of local efforts to end deforestation and degradation and to expand restoration, with global efforts to stop greenhouse gas emissions.

Human impacts outpace natural processes in the Amazon.

Amazonian environments are being degraded by modern industrial and agricultural activities at a pace far above anything previously known, imperiling its vast biodiversity reserves and globally important ecosystem services. The most substantial threats come from regional deforestation, because of export market demands, and global climate change. The Amazon is currently perched to transition rapidly from a largely forested to a nonforested landscape. These changes are happening much too rapidly for Amazonian species, peoples, and ecosystems to respond adaptively. Policies to prevent the worst outcomes are known and must be enacted immediately. We now need political will and leadership to act on this information. To fail the Amazon is to fail the biosphere, and we fail to act at our peril.

Epidemiology and georeferencing of squamous cell carcinoma cases and their relationship with pesticides / Epidemiologia e georreferenciamento dos casos de carcinoma epidermóide de boca e sua relação com agrotóxicos

ABSTRACT Objective To assess the prevalence of epidermoid carcinoma cases, georeference their locations, and seek to correlate them to areas with higher agricultural production and use of pesticides. Methods This was a cross-sectional, descriptive and retrospective study conducted by searching the histopathological reports with confirmed diagnosis of epidermoid carcinoma of the mouth issued from August 2005 to December 2011 by the public oral pathology laboratory of the State of Mato Grosso, Brazil. Data were plotted with the IBM SPSS Statistics software and spatial analysis used the ArcGIS 10.1 software. Results There were a higher number of diagnoses in 2007 (26.6%); 99 cases (75%) of patients were male; 96 cases (72.8%) were patients aged between 41 and 70 years; and the cities of Cuiabá, Várzea Grande and Rondonópolis respectively showed the highest number of occurrences. Conclusion No relationship was found between the occurrence of cases of epidermoid carcinoma and the municipalities with high agricultural production and pesticide use.

RESUMO Objetivo Analisar a prevalência dos casos de carcinoma epidermóide e fazer seu georreferenciamento, buscando correlaciona-los às áreas de maior produção agrícola e utilização de agrotóxicos. Métodos Trata-se de um estudo transversal, descritivo e retrospectivo realizado por meio de pesquisa dos laudos histopatológicos com diagnóstico confirmado de carcinoma epidermóide de boca emitidos de agosto de 2005 a dezembro de 2011 pelo serviço de patologia bucal do laboratório público do Estado de Mato Grosso. Os dados foram tabulados com o software IBM SPSS Statistics e a análise espacial utilizou o software ArcGIS 10.1. Resultados Houve um maior número de diagnósticos no ano de 2007 (26,6%), 99 casos (75%) eram de pacientes do sexo masculino; 96 casos (72,8%) eram de pacientes na faixa etária compreendida entre 41 e 70 anos e os municípios de Cuiabá, Várzea Grande e Rondonópolis apresentam respectivamente o maior número de ocorrências. Conclusão Não foi encontrada relação entre a ocorrência dos casos de carcinoma epidermóide de boca e os municípios com grande produção agrícola e elevado uso de agrotóxicos.