Environmental equity is a concept derived from the (un)equal exposure to environmental degradation by different social groups, usually minorities and low-income people exposed to major environmental risks, also known as environmental justice. It is assumed that no group of people, independent of race, ethnicity or socio-economic class, should support, either in concentrated or unevenly distributed form, the negative environmental impacts resulting from industrial, agricultural, commercial and infrastructure activities or government programs and policies. In this paper the concept of environmental equity is explored as a criterion for water management through the analysis of a typical coupled human–natural system: the Epitácio Pessoa Reservoir, located in the semi-arid region of Brazil. Inefficient water resource management has caused unequal access to water by the population, particularly during drought periods. However, census data indicate that population have practically the same access to water, which actually is not able to reflect the actual picture. This study argues that environmental equity can be an additional criterion to improve water management.

Water availability for a range of human uses will increasingly be affected by climate change, especially in the arid and semiarid tropics. The main objective of this study is to evaluate the infrastructure sufficiency in meeting water demand under climate-induced socio-hydrological transition in the Capibaribe River basin (CRB). The basin has experienced spatial and sectoral (agriculture-to-urban) reconfiguration of water demands. Human settlements that were once dispersed, relying on intermittent sources of surface water, are now larger and more spatially concentrated, which increases water-scarcity effects. Based on the application of linked hydrologic and water-resources models using precipitation and temperature projections of the IPCC SRES (Special Report: Emissions Scenarios) A1B scenario, a reduction in rainfall of 26.0% translated to streamflow reduction of 60.0%. We used simulations from four members of the HadCM3 (UK Met Office Hadley Centre) perturbed physics ensemble, in which a single model structure is used and perturbations are introduced to the physical parameterization schemes in the model (Chou et al., 2012). We considered that the change of the water availability in the basin in the future scenarios must drive the water management and the development of adaptation strategies that will manage the water demand. Several adaptive responses are considered, including water-loss reductions, wastewater collection and reuse, and rainwater collection cisterns, which together have potential to reduce future water demand by 23.0%. This study demonstrates the vulnerabilities of the infrastructure system during socio-hydrological transition in response to hydroclimatic and demand variabilities in the CRB and also indicates the differential spatial impacts and vulnerability of multiple uses of water to changes over time. The simulations showed that the measures proposed and the water from interbasin transfer project of the São Francisco River had a positive impact over the water supply in the basin, mainly for human use. Industry and irrigation will suffer impact unless other measures are implemented for demand control.

Background
New sources of hydroclimate information based on forecast models and observational data have the potential to greatly improve the management of water resources in semi-arid regions prone to drought. Better management of climate-related risks and opportunities requires both new methods to develop forecasts of drought indicators and river flow, as well as better strategies to incorporate these forecasts into drought, river or reservoir management systems. In each case the existing institutional and policy context is key, making a collaborative approach involving stakeholders essential.

Methods
This paper describes work done at the IRI over the past decade to develop statistical hydrologic forecast and water allocation models for the semi arid regions of NE Brazil (the “Nordeste”) and central northern Chile based on seasonal climate forecasts.

Results
In both locations, downscaled precipitation forecasts based on lagged SST predictors or GCM precipitation forecasts exhibit quite high skill. Spring-summer melt flow in Chile is shown to be highly predictable based on estimates of previous winter precipitation, and moderately predictable up to 6 months in advance using climate forecasts. Retrospective streamflow forecasts here are quite effective in predicting reductions in water rights during dry years. For the multi-use Oros reservoir in NE Brazil, streamflow forecasts have the most potential to optimize water allocations during multi-year low-flow periods, while the potential is higher for smaller reservoirs, relative to demand.

Conclusions
This work demonstrates the potential value of seasonal climate forecasting as an integral part of drought early warning and for water allocation decision support systems in semi-arid regions. As human demands for water rise over time this potential is certain to rise in the future.

Sustainable adaptation to climate change needs to be assessed beyond the present time and location to include the way that current forms of adaptation might influence future response options. An analysis of past dynamics of adaptation, what we call “trajectories,” might hold the key to understanding how the adaptive outcomes of past responses to climate stress constrain or open avenues to future adaptation. Adaptation research often focuses on particular actions, technologies, or institutions which may positively influence these relationships in order to build resilience and reduce vulnerability. However, relationships are complex and often behave in unexpected ways. There is no simple cause and effect, but rather actions are modified and transmitted through a web of linkages and feedbacks that are both physical and social. This complexity challenges our ability to predict the outcome of particular actions and there remain gaps in the understanding of system interactions that would permit a more accurate assessment of future development trajectories. The work presented here is an analysis of change in the climate vulnerability of dryland farmers in Northeast Brazil over four decades. The analytical framework, which links biophysical characteristics with a socio-economic context and indicators, permits an analysis that captures the dynamic relationship of adaptive capacities and consequent changes in vulnerability. The analysis of trajectories provides a foundation for future assumptions about human behavior and the relationship with the environment.

Os modelos globais do quarto relatório do Intergovernmental Panel on Climate Change (IPCC-AR4) são avaliados para o Nordeste Setentrional do Brasil (NEB) quanto à representação da variabilidade interanual e interdecadal da precipitação para o período de 1901 a 1999 e são analisadas as projeções do cenário A1B. Essa avaliação é realizada
utilizando-se os dados do Climatic Research Unit (CRU) e a reanálise 20th Century Reanalysis V2 do National Oceanic and Atmospheric Administration (NOAA). É aplicada a transformada em ondeletas à série de dados para detectar e analisar os padrões de variabilidades existentes no século XX. Os resultados sugerem que os modelos CSIRO_MK3_0_RUN2, GISS_MODEL_E_R_RUN8 e UKMO_HADCM3_RUN1 reproduziram de maneira satisfatória a variabilidade plurianual. Os modelos divergem quanto o futuro da precipitação no NEB, alguns indicam impactos positivos na média anual de até 12% e outros impactos negativos de até 42%.

O objetivo do presente estudo foi analisar a distribuição espacial dos componentes da evapotranspiração de referência modificada (ETr) no Brasil e, posteriormente, a variabilidade temporal por meio da técnica da análise harmônica. Para isso, foi feita inicialmente uma análise de variância, fase e amplitude para o tempo presente (1980-2000) e, em seguida, feita uma projeção com o tempo futuro (2080-2100), com base no cenário A2 do Painel Intergovernamental para as Mudanças Climáticas. A equação utilizada foi a de Penman-Monteith, padronizada pela Food and Agriculture and Organization of the United Nations (FAO) 1998. As simulações foram conduzidas com o modelo regional de clima (MM5), acoplado a um modelo de vegetação potencial (MVP). Os termos aerodinâmico e radiativo apresentaram um ciclo anual que é dominante na região amazônica e Sul do Brasil, enquanto na região Sudeste o ciclo semestral tem maior destaque. As maiores variações na amplitude da ETr foram identificadas no semiárido nordestino e no extremo sul do Brasil. As mudanças na ETr, devido ao aquecimento global, foram máximas na região central do Brasil e Amazônica. Ainda foi observado que, sob condições de aquecimento global, as variações do termo aerodinâmico tornam-se mais importantes do que as variações do termo radiativo para a ETr total.

Climate change is expected to alter a multitude of factors important to agricultural systems, including pests, diseases, weeds, extreme climate events, water respources, soil degradation, and socio-economic pressures. Changes to carbon dioxide concentrations ([CO2]), temperature and water (CTW) will be the primary drivers of climate change in crop growth and agricultural systems. Therefore, establishing the CTW-chnage sensitivity of crop yields is an urgent research need and warrants diverse methods of investigation.

As mudanças no uso e na ocupação do solo, provocadas pelas ações antrópicas, têm gerado grandes impactos nas paisagens. Esses impactos podem ser mitigados através do monitoramento do uso e da cobertura do solo utilizando-se informações espaço-temporais das modificações ocorridas na paisagem. Este trabalho apresenta uma análise espaço-temporal detalhada da dinâmica do uso e ocupação do solo da bacia hidrográfica do riacho São Paulo, localizada na região semiárida do Estado de Pernambuco, entre os anos de 1991 e 2010. Partindo da classificação de três imagens de satélite dos anos de 1991, 2000 e 2010, foram utilizadas matrizes de transição, associadas à álgebra de mapas e métricas da paisagem. Os resultados mostraram que durante o período estudado as classes de uso e ocupação do solo passaram por uma grande transição, com a substituição progressiva das áreas de vegetação de caatinga aberta por áreas com pastagem/agricultura. Junto com o rápido crescimento da classe pastagem/agricultura, a paisagem predominante de vegetação nativa foi sendo substituída por uma paisagem cada vez mais devastada, heterogênea e fragmentada, como mostraram os índices das métricas da paisagem.

Numerical studies on impacts of landscape fragmentation due to land use and land cover change (LUCC) on precipitation fields over the Ji-Paraná basin in the Amazon region are carried out using atmospheric Eta model. Experiments consider historical data about LUCC over the basin from 1978 to 2000 and compare simulations under LUCC conditions with simulations under pristine conditions. In agreement with previous observational studies, model results do not show statistically significant impacts on precipitation in the region. Results indicate that variability in precipitation in this region is mainly controlled by large-scale atmospheric characteristics and soil moisture conditions. However, some limitations are identified in the model simulations, mainly associated to the diurnal cycle of precipitation.