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The Amazon has a well-defined wet austral summer monsoon and dry winter monsoon precipitation regime and experienced a sequence of drought events in the last 13 years. This study performs a comparative assessment of observed and predicted climate conditions during the three most recent drought events in the Amazon, in 19971998, 20042005 and 20092010, with emphasis on how these events affected the regional monsoon-like precipitation regime. A century long Negro River level time series at Manaus is investigated, applying extreme values theory for estimating return periods of these major drought events. Possible teleconnections of river levels at Manaus and sea surface temperature at remote regions are explored. Large scale oceanic and atmospheric conditions are investigated to highlight the mechanisms associated with the observed drought conditions, particularly during the dry monsoon season. Satellite estimates are used for diagnosing biomass burning aerosol and discuss possible contributions to the observed precipitation deficits in the 2005 and 2010 drought events during the dry monsoon season. The study is concluded with an analysis of the performance of seasonal precipitation predictions for the dry monsoon seasons of July to September 1998, 2005 and 2010 produced with the operational seasonal prediction system used at the Center for Weather Forecasts and Climate Studies (CPTEC) of the Brazilian National Institute for Space Research (INPE). This system was capable of producing 1 month in advance drought warning for the three investigated events, relevant for helping the government and local population make decisions for reducing drought impacts in the Amazon region.

The controversy dubbed Climategate erupted in late 2009 exactly as diplomats around the world were preparing their positions for the negotiations at the especially high-profile 15th Conference of the Parties under the United Nations Framework Convention on Climate Change (UNFCCC). This meeting was deemed by many commentators as especially crucial for the definition of an international agreement about post-2012 measures to limit emissions of greenhouse gases. The controversy concerned the leaking or stealing of thousands of private e-mails and documents sent and received by climate researchers at the Climatic Research Unit (CRU) at the University of East Anglia in the United Kingdom. The materials content provided a rare, uncensored glimpse into the fractious world of climate science, including frank conversations among scientific leaders of the United Nations Intergovernmental Panel on Climate Change (IPCC), the scientific body which evaluates the evidence of anthropogenic climate change to inform decision making under the UNFCCC. The e-mails discussed sensitive topics such as possible holes in key scientific evidence and expressions of the scientists desires and strategizing to avoid granting countervailing science scientific legitimacy, weight, and public visibility.

This work analysed heavy rainfall events and their predictability on Rio de Janeiro, Brazil, using rain gauge data from 2000 to 2010, atmospheric model outputs, and an artificial neural network based on adaptive resonance theory. The latter was applied on top of atmospheric simulations for 2009 and 2010, and we were able to predict 55% of the heavy rainfall events using a combination of relative humidity at 900 hPa and meridional winds at 10 m for a domain covering central and southern Brazil, which represents a relative gain of 67% on predictability when compared to the model predicted rainfall.

The potential impact of deforestation in the Brazilian Amazon on greenhouse gas emissions to the atmosphere calls for policies that take account of changes in forest cover. Although much research has focused on the location and effects of deforestation, little is known about the distribution and reasons for the agricultural uses that replace forest cover. We used Landsat TM-based deforestation and agricultural census data to generate maps of the distribution and proportion of four major agricultural land uses throughout the Brazilian Amazon in 1997 and 2007. We built linear and spatial regression models to assess the determinant factors of deforestation and those major agricultural land uses e pasture, temporary agriculture and permanent agriculture e for the states of Pará, Rondônia, and Mato Grosso. The data include 30 determinant factors that were grouped into two years (1996 and 2006) and in four categories: accessibility to markets, public policies, agrarian structure, and environment. We found an overall expansion of the total agricultural area between 1997 and 2007, and notable differences between the states of Pará, Rondônia, and Mato Grosso in land use changes during this period. Regression models for deforestation and pasture indicated that determinant factors such as distance to roads were more influential in 1997 than in 2007. The number of settled families played an important role in the deforestation and pasture, the effect was stronger in 2007 than 1997. Indigenous lands were significant in preventing deforestation in high-pressure areas in 2007. For temporary and permanent agricultures, our results show that in 1997 the effect of small farms was stronger than in 2007. The mapped land use time series and the models explain empirically the effects of land use changes across the region over one decade.

South America has experienced signifi cant land use transitions in the past, especially due to the expansion of large-scale agriculture in countries such as Brazil and Argentina. This expansion has supported economic growth, but has caused serious environmental consequences. Therefore, countries in South America will continue to face major public policy decisions if they are to combine economic growth, income distribution, and environmental sustainability. Against this background, scientists came together in November 2011 in Ilhabela, Brazil for a GLP sponsored workshop to discuss four main topics linked to the sustainable future of the region: governance and institutions, vulnerability, environmental services and modeling and data provision & analysis. This article provides a general overview of the workshop outcomes.

LuccME is an open-source framework for the development of spatially explicit land use and cover change models, built as an extension of the TerraME programming environment. LuccME simplifi es the creation of deforestation, agricultural expansion, urban sprawl and other land change processes at different scales by combining basic components or developing new ones. The goals are to provide a collaborative platform for scientifi c advances in fi eld, and to disseminate the use of dynamic models beyond the academic world. The framework was released last November during the GLP Workshop on Land Use Transitions in South America, and can be freely downloaded from http://www.terrame.org/luccme.

The objective of this work is to evaluate climate simulations over South America using the regional Eta Model driven by four members of an ensemble of the UK Met Office Hadley Centre HadCM3 global model. The Eta Model has been modified with the purpose of performing long-term decadal integrations and has shown to reproduce present climatethe period 19611990reasonably well when forced by HadCM3. The global model lateral conditions with a resolution of 2.5 latitude 9 3.75 longitude were provided at a frequency of 6 h. Each member of the global model ensemble has a different climate sensitivity, and the four members were selected to span the range of uncertainty encompassed by the ensemble. The Eta Model nested in the HadCM3 global model was configured with 40-km horizontal resolution and 38 layers in the vertical. No large-scale internal nudging was applied. Results are shown for austral summer and winter at present climate defined as 196190. The upper and low-level circulation patterns produced by the Eta-CPTEC/HadCM3 experiment set-up show good agreement with reanalysis data and the mean precipitation and temperature with CRU observation data. The spread in the downscaled mean precipitation and temperature is small when compared against model errors. On the other hand, the benefits in using an ensemble is clear in the improved representation of the seasonal cycle by the ensemble mean over any one realization. El Nino and La Nina years were identified in the HadCM3 member runs based on the NOAA Climate Prediction Center criterion of sea surface temperature anomalies in the Nino 3.4 area. The frequency of the El Nino and La Nina events in the studied period is underestimated by HadCM3. The precipitation and temperature anomalies typical of these events are reproduced by most of the Eta-CPTEC/HadCM3 ensemble, although small displacements of the positions of the anomalies occur. This experiment configuration is the first step on the implementation of Eta-CPTEC/HadCM3 upcoming experiments on climate change studies that are discussed in a companion paper.

We evaluated how land use change affected the nitrogen cycle and greenhouse gas fluxes. We measured soil temperature and water-filled pore space (WFPS), as well as nitrate and ammonium concentrations, mineralization and nitrification rates, and flux of CH4, CO2 and N2O in soils of pasture catchment and in soils of a forest catchment located on the north coast of the State of São Paulo. The main vegetation type in the forest catchment is primary Atlantic Montane Forest, while the pasture is an unfertilized 40-year old area planted with Brachiaria humidicola. Four plots were used for monthly sampling in each land use for an entire year. Soil temperature was always higher in pasture than in forest soils, while WFPS was lower in the pasture in relation to forest soils. Pasture soils were a weak source of CH4 during the winter months and a less strong sink of methane than the forest soils during the rainy summer months of the year. The annual median CH4 uptake was -1.8±1.0mgm-2d-1 in the forest in contrast to -0.6±0.9mgm-2d-1 in pasture soils. CO2 emissions were similar in the winter, but higher in the summer months in pasture soils in relation to forest soils. The annual median flux in the forest was 4.2±1.5μmolm-2s-1 and increased in the pasture to 6.5±2.9μmolm-2s-1. In contrast, N2O fluxes were smaller in the pasture (0.3±0.7ngcm-2h-1) than in forest soils (0.5±0.5ngcm-2h-1).

El Informe Especial sobre la Gestión de Riesgos de Eventos Extremos y Desastres en América Latina y el Caribe (SREX) fue encargado por el Panel Intergubernamental sobre el Cambio Climático (IPCC) en respuesta a la necesidad de proporcionar una asesoría específica sobre el cambio climático y los eventos meteorológicos y climáticos extremos (‘extremos climáticos’). El informe fue elaborado durante los últimos dos años y medio (2009-2011) con la participación de 220 autores expertos/as, 19 editores revisores/as y tomando en cuenta casi 19.000 comentarios. Es producto de tres rigurosos procesos de redacción, con revisión por parte de expertos/as y funcionarios/as gubernamentales. Los resultados, conclusiones y recomendaciones fueron aprobados por 194 gobiernos después de una reunión de cuatro días, en la que se aprobó el Resumen para Formuladores/as de Políticas.

O Relatório Especial sobre Gerenciamento de Riscos de Eventos Extremos e Desastres para Promover Adaptação à Mudança do Clima (SREX) foram comissionados pelo Painel Intergovernamental sobre Mudança do Clima (IPCC) em resposta a uma reconhecida necessidade de fornecer conselhos específicos sobre mudança do clima, condições meteorológicas extremas e eventos climáticos (‘extremos climáticos’). O relatório SREX levou mais de dois anos e meio para ser escrito, foi compilado por 220 autores especialistas, 19 editores revisores, e levou em conta mais de 19.000 comentários.

This paper reviews recent progress made in our understanding of the functioning and variability of the South American Monsoon System (SAMS) on time scales varying from synoptic to long-term variability and climate change. The SAMS contains one of the most prominent summertime climate patterns in South America, featuring a strong seasonal variability in a region lying between the Amazon and the La Plata Basin. Much of the recent progress is derived from complementary international programs, such as the Monsoon Experiment South America (MESA), as well as from ongoing international programs such as the Large Scale Biosphere Atmosphere Experiment in the Amazon Basin (LBA) and the La Plata Basin (LPB) Regional Hydroclimate Project, which includes the CLARIS LPB Europe-South America Network for Climate Change Assessment and Impact Studies in La Plata Basin Project. The latter assesses atmosphere-land surface interactions, the role of land use changes and aerosols from biomass burning considered as sources of variability and change in the SAMS functioning, characteristics and behaviour. The SAMS region is particularly susceptible to variations of climate due to the importance of hydroelectricity generation and the agricultural base of local economies. Also addressed in this report are projections of climate change and extremes, which are important for impact and vulnerability assessments. This discussion includes the need to identify and understand important processes that control the monsoonal climate, how these processes may vary and change, and how they may interact with key societal sectors, including water resource management, hydroelectric generation, agriculture, and agribusiness. This paper reports on the major contributions of MESA to the knowledge of characteristics, functioning and variability of the SAMS, and is based on recent studies and publications, and can be considered as an update of a previous review by C. S. Vera et al. (2006a).