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This study discusses the climatological aspects of the most severe drought ever recorded in the semiarid region Northeast Brazil. Droughts are recurrent in the region and while El Nino has driven some of these events others are more dependent on the tropical North Atlantic sea surface temperature fields. The drought affecting this region during the last 5 years shows an intensity and impact not seen in several decades in the regional economy and society. The analysis of this event using drought indicators as well as meteorological fields shows that since the middle 1990s to 2016, 16 out of 25 years experienced rainfall below normal. This suggests that the recent drought may have in fact started in the middle-late 1990s, with the intense droughts of 1993 and 1998, and then the sequence of dry years (interrupted by relatively wet years in 2007, 2008, 2009 and 2011) after that may have affected the levels of reservoirs in the region, leading to a real water crisis that was magnified by the negative rainfall anomalies since 2010.

Disasters have been affecting several municipalities listed as cultural heritage sites, as highlighted by the media stories of the 2010 January floods in Sao Luiz do Paraitinga city, Sao Paulo state. This paper shared some findings related to two phases of research. The first phase occurred from January 2010 to June 2013, when of the authors studied the long term disaster recovery process. The second phase was developed from October 2014 to October 2016, when an educational project was run to create intergenerational capacities of disaster risk prevention, articulating the early warning system and educational sectors. The findings denote the need of strengthening the linkages between cultural heritage sector and disaster risk prevention.

Context: Global environmental change and disasters pose several challenges to governments, society and science. These challenges occurred in social contexts were information and communication technologies can be used to share data and information, engaging citizen scientists in multidirectional and decentralized knowledge creation initiatives. Often referenced as participatory (or people-centered) early warning systems, this has been of a great potential to improve decisions taken by both emergency institutions and exposed and/or affected communities. Several methodologies have been proposed, mainly in natural science, redefining traditional ways of transferring knowledge about scientific process to the public. Gap: However, practice and research still lack studies that investigate how citizens can be involved in citizen science to support early warning systems. From a social science perspective, this is important as these works do not fill the gap between citizen science and disaster prevention. While, on a technological perspective, efforts have been concentrated on developing systems, methodologies, and approaches rather than understanding citizens requirements or ways of better engaging citizens. Objective: This paper provides a social science framework to determine the elements of how citizen science and participatory early warning systems can be bridged. Method: For doing so, we will conduct a systematic mapping for examining the literature on citizen science and disaster management, in particular, those focused on social science and participatory approaches for early warning systems. Results: This review showed that only 3,43% (14 of 408) articles were related to citizen science and P-EWS, which indeed indicate that much effort is needed to disseminate what is citizen science and how it can be mainstreamed in DRM field. Furthermore, the proposed framework can contribute by enhancing stakeholders reflexivity about EWS.

The objective of this work is to assess changes in three metropolitan regions of Southeast Brazil (Rio de Janeiro, São Paulo, and Santos) based on the projections produced by the Eta Regional Climate Model (RCM) at very high spatial resolution, 5 km. The region, which is densely populated and extremely active economically, is frequently affected by intense rainfall events that trigger floods and landslides during the austral summer. The analyses are carried out for the period between 1961 and 2100. The 5-km simulations are results from a second downscaling nesting in the HadGEM2-ES RCP4.5 and RCP8.5 simulations. Prior to the assessment of the projections, the higher resolution simulations were evaluated for the historical period (19611990). The comparison between the 5-km and the coarser driver model simulations shows that the spatial patterns of precipitation and temperature of the 5-km Eta simulations are in good agreement with the observations. The simulated frequency distribution of the precipitation and temperature extremes from the 5-km Eta RCM is consistent with the observed structure and extreme values. Projections of future climate change using the 5-km Eta runs show stronger warming in the region, primarily during the summer season, while precipitation is strongly reduced. Projected temperature extremes show widespread heating with maximum temperatures increasing by approximately 9 °C in the three metropolitan regions by the end of the century in the RCP8.5 scenario. A trend of drier climate is also projected using indices based on daily precipitation, which reaches annual rainfall reductions of more than 50 % in the state of Rio de Janeiro and between 40 and 45 % in São Paulo and Santos. The magnitude of these changes has negative implications to the population health conditions, energy security, and economy.

In Lyra et al. (2017), regarding the sentence in page 4, section 2.4, first column, second paragraph: The MRRJ is located in the state of Rio de Janeiro.This area of approximately 5 million km2 with a population of almost 12 million people (CEPERJ 2010) is the second largest urban agglomeration in Brazil and the twentieth largest in the world (IBGE 2010). The MRSP is approximately 8 million km2 with a populationof approximately 21 million people (IBGE 2010).The sentence should read: TheMRRJ is located in the state of Rio de Janeiro. This area of approximately 5 thousand km2 with a population of almost 12 million people (IBGE 2010). million people (CEPERJ 2010) is the second largest urban agglomeration in Brazil and the twentieth largest in the world (IBGE 2010). TheMRSP is approximately 8 thousand km2 with a population of approximately 21 million people (IBGE 2010)..2.4, first column, second paragraph: The MRRJ is located in the state of Rio de Janeiro. This area of approximately 5 million km2 with a population of almost 12 million people (CEPERJ 2010) is the second largest urban agglomeration in Brazil and the twentieth largest in the world (IBGE 2010). The MRSP is approximately 8 million km2 with a population of approximately 21 million people (IBGE 2010). The sentence should read: BTheMRRJ is located in the state of Rio de Janeiro. This area of approximately 5 thousand km2 with a population of almost 12 million people (CEPERJ 2010) is the second largest urban agglomeration in Brazil and the twentieth largest in the world (IBGE 2010). TheMRSP is approximately 8 thousand km2 with a population of approximately 21 million people (IBGE 2010).

One of the main barriers to increasing the solar energy share is its intermittency. Solar energys large variability in different timescales is driven by natural solar astronomical cycles and weather. Ground-based measurements are important for evaluating variability at high temporal resolutions, but they are only representative of small areas close to the measurement sites. Satellite observations come as an alternative to analysis over large areas. However, they have coarse temporal and spatial resolutions. In our study, we first evaluated the variability in different time steps, using one-year of 1-min resolution ground-based irradiance measured at three sites located in different Brazilian climate regimes. The results showed that more humid months have the largest variability. By contrast, the driest locations presented more variability on short timescales, probably due to the presence of a large number of clouds, even in very dry conditions. This characteristic can be of concern to Brazilian energy planning since the site is located in the most prominent region for solar energy generation. We also compared ground observations with satellite cloud variability, with 30-min resolution. For the same timescale, the results were promising, with a Pearson correlation of up to 0.93, depending on the site. However, when the frequency of the solar irradiance measurements increased, the correlation decreased. A solution may be to analyze a larger pixel area around the sites. Another option would be the use of downscaling methods. This topic, however, will be the subject of the future study. The most important result achieved in this study was the development of a simple methodology for evaluating the surface solar irradiance variability using cloud cover obtained from visible satellite imagery.

Clouds are the major modulator of the shortwave and longwave radiation components of the Earth’s energy balance and, as such, help to regulate the planet’s temperature. In the energy sector, clouds are a source of instability in the generation of energy using solar technologies. This study aims at comparing three approaches to get cloud cover information in the Southeastern region of Brazil during the period of approximately three months. The first method, assumed as reference, uses all-sky camera pictures for the cloud cover estimation. The other two methodologies use downward longwave radiation with surface meteorological data and geostationary satellite data. Both methods presented good agreement with the camera for clear sky and overcast conditions, with probabilities of detection of 92.8% and 80.7% for the longwave method and 93.3% and 87.6% for the satellite method, respectively. The major problem occurs with the broken-clouds sky scenario, with probabilities of detection above 38%, where each method has its own specificity, such as, longwave emissivity of the atmosphere, spatial resolution and view geometry. The long-wave method has the minor R correlation with the camera (87%) when compared with the satellite method (93%) and requires a daily normalization, which make it not usable for instantaneous measurements. Regarding the satellite method, the most important issue is the spatial resolution, which has the major impact on the broken-clouds sky scenarios. The cloud masking works properly for large clouds with, at least, the size comparable to the satellite image pixel. Furthermore, the method using the all-sky camera also needs to be improved, because it presented some deficiencies, like very bright areas around the sun, sometimes identified as clouds, leading to cloud cover overestimation.

Large uncertainties still dominate the hypothesis of an abrupt large-scale shift of the Amazon forest caused by climate change [Amazonian forest dieback (AFD)] even though observational evidence shows the forest and regional climate changing. Here, we assess whether mitigation or adaptation action should be taken now, later, or not at all in light of such uncertainties. No action/later action would result in major social impacts that may influence migration to large Amazonian cities through a causal chain of climate change and forest degradation leading to lower river-water levels that affect transportation, food security, and health. Net-present value socioeconomic damage over a 30-year period after AFD is estimated between US dollar (USD) $957 billion (×109) and $3,589 billion (compared with Gross Brazilian Amazon Product of USD $150 billion per year), arising primarily from changes in the provision of ecosystem services. Costs of acting now would be one to two orders of magnitude lower than economic damages. However, while AFD mitigation alternatives-e.g., curbing deforestation-are attainable (USD $64 billion), their efficacy in achieving a forest resilience that prevents AFD is uncertain. Concurrently, a proposed set of 20 adaptation measures is also attainable (USD $122 billion) and could bring benefits even if AFD never occurs. An interdisciplinary research agenda to fill lingering knowledge gaps and constrain the risk of AFD should focus on developing sound experimental and modeling evidence regarding its likelihood, integrated with socioeconomic assessments to anticipate its impacts and evaluate the feasibility and efficacy of mitigation/adaptation options.

National climate policies are shaped by international organizations (IOs) and global norms. Drawing from World Society Theory and the Advocacy Coalition Framework (ACF), we develop two related arguments: (1) one way in which IOs can influence national climate policy is through their engagement in mass-mediated national policy debates and (2) national organizations involved in the policy process may form advocacy coalitions to support or oppose the norms promoted by IOs. To examine the role of IOs in national policy debates and the coalitions that support and oppose them, we use discourse network analysis (DNA) on over 3500 statements in 11 newspapers in Canada, the United States (US), Brazil, and India. We find that in the high-income countries that are high per capita emitters (Canada and the US), IOs are less central in the policy debates and the discourse network is strongly clustered into competing advocacy coalitions. In the lower-income countries that are low per capita emitters (Brazil and India), IOs are more central and the discourse network is less clustered. Relating these findings to earlier research, we suggest that the differences we find between high and low per capita emitters may be to some extent generalizable to the relevant country groups beyond our four cases.

The tropical carbon balance dominates year-to-year variations in the CO2 exchange with the atmosphere through photosynthesis, respiration and fires. Because of its high correlation with gross primary productivity (GPP), observations of sun-induced fluorescence (SIF) are of great interest. We developed a new remotely sensed SIF product with improved signal-to-noise in the tropics, and use it here to quantify the impact of the 2015/2016 El Niño Amazon drought. We find that SIF was strongly suppressed over areas with anomalously high temperatures and decreased levels of water in the soil. SIF went below its climatological range starting from the end of the 2015 dry season (October) and returned to normal levels by February 2016 when atmospheric conditions returned to normal, but well before the end of anomalously low precipitation that persisted through June 2016. Impacts were not uniform across the Amazon basin, with the eastern part experiencing much larger (10-15%) SIF reductions than the western part of the basin (2-5%). We estimate the integrated loss of GPP relative to eight previous years to be 0.34-0.48 PgC in the three-month period October-November-December 2015.This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

The objective of this work is to assess the downscaling projections of climate change over Central America at 8-km resolution using the Eta Regional Climate Model, driven by the HadGEM2-ES simulations of RCP4.5 emission scenario. The narrow characteristic of continent supports the use of numerical simulations at very high-horizontal resolution. Prior to assessing climate change, the 30-year baseline period 19611990 is evaluated against different sources of observations of precipitation and temperature. The mean seasonal precipitation and temperature distribution show reasonable agreement with observations. Spatial correlation of the Eta, 8-km resolution, simulations against observations show clear advantage over the driver coarse global model simulations. Seasonal cycle of precipitation confirms the added value of the Eta at 8-km over coarser resolution simulations. The Eta simulations show a systematic cold bias in the region. Climate features of the Mid-Summer Drought and the Caribbean Low-Level Jet are well simulated by the Eta model at 8-km resolution. The assessment of the future climate change is based on the 30-year period 20212050, under RCP4.5 scenario. Precipitation is generally reduced, in particular during the JJA and SON, the rainy season. Warming is expected over the region, but stronger in the northern portion of the continent. The Mid-Summer Drought may develop in regions that do not occur during the baseline period, and where it occurs the strength may increase in the future scenario. The Caribbean Low-Level Jet shows little change in the future. Extreme temperatures have positive trend within the period 20212050, whereas extreme precipitation, measured by R50mm and R90p, shows positive trend in the eastern coast, around Costa Rica, and negative trends in the northern part of the continent. Negative trend in the duration of dry spell, which is an estimate based on evapotranspiration, is projected in most part of the continent. Annual mean water excess has negative trends in most part of the continent, which suggests decreasing water availability in the future scenario.

The outstanding tropical land climate characteristic over the past decades is rapid warming, with no significant large-scale precipitation trends. This warming is expected to continue but the effects on tropical vegetation are unknown. El Nino-related heat peaks may provide a test bed for a future hotter world. Here we analyse tropical land carbon cycle responses to the 2015/16 El Nino heat and drought anomalies using an atmospheric transport inversion. Based on the global atmospheric CO2 and fossil fuel emission records, we find no obvious signs of anomalously large carbon release compared with earlier El Nino events, suggesting resilience of tropical vegetation. We find roughly equal net carbon release anomalies from Amazonia and tropical Africa, approximately 0.5 PgC each, and smaller carbon release anomalies from tropical East Asia and southern Africa. Atmospheric CO anomalies reveal substantial fire carbon release from tropical East Asia peaking in October 2015 while fires contribute only a minor amount to the Amazonian carbon flux anomaly. Anomalously large Amazonian carbon flux release is consistent with downregulation of primary productivity during peak negative near-surface water anomaly (October 2015 to March 2016) as diagnosed by solar-induced fluorescence. Finally, we find an unexpected anomalous positive flux to the atmosphere from tropical Africa early in 2016, coincident with substantial CO release.