Migrant birds may be vulnerable to climate change at different stages of their annual cycles especially on the breeding grounds, where changes in phenology may affect their ability to synchronise breeding with the peak of resources availability. Understanding how phenology of breeding, survival and productivity varies between and within years is therefore crucial to understand migrant population dynamics. This thesis describes this variation in the Cyprus Wheatear Oenanthe cypriaca, with particular emphasis on a colour-ringed population at Troodos, Cyprus, 2010-2012. Our results suggest that the phenology of breeding of Cyprus Wheatear is variable with breeding onset and number of breeding attempts probably varying with annual temperature variation. Minimum true survival rates were very high for a small passerine migrant, although they were probably sufficiently annually variable to profoundly affect annual population dynamics. For productivity, nest survival was very high and did not vary between years, or nesting attempts, or with clutch initiation date but it was significantly higher in the chick stage versus the egg stage. Post-fledging survival in the first 4 weeks was very high. Renesting probability was significantly different in all years, yet total productivity per pair was the same in each of three years. Cyprus Wheatears at Troodos showed such high productivity and survival that the population must be a major source population and this was reflected in the very high density of breeding pairs at the study site. Finally we used altitude as a proxy for variation in temperature and investigated how abundance, productivity and phenology in Cyprus Wheatears varied between and within years, from sea level to 1952m, using transect surveys to record breeding birds across Cyprus. Cyprus Wheatears were common in all habitats and altitudes; altitudinal temperature variation probably affected the occurrence of double brooding and so the timing of chick production, but not the onset of breeding. The results suggest that Cyprus Wheatears are already very well adapted to high variation in temperature within and between seasons, changing investment accordingly.

Orientador: Jonas Teixeira Nery / Banca: Viviane Regina Algarve / Banca: Iris Amati Martins / Resumo: Alterações no clima causam impactos significativos sobre a estrutura e distribuição dos ecossistemas afetando a biodiversidade terrestre. O objetivo da pesquisa foi descrever os padrões da dinâmica da vegetação natural da Mata Atlântica Paulista na região da bacia hidrográfica do rio Paraíba do Sul (UGRHI 2) e identificar a relação que se estabelece entre a variabilidade climática e a vegetação. Dados de imagens de séries temporais de índices de vegetação como o EVI (Índice de Vegetação Melhorado), LSWI (Índice de umidade da vegetação) e LAI (Índice de Área Foliar) derivados de produtos de Sensoriamento Remoto (SR), foram adquiridos do sensor MODIS, pois são poderosas ferramentas indicadoras do desenvolvimento da vegetação. Dados de precipitação pluvial adquiridas por estações pluviométricas disponibilizadas pela ANA foram aplicados para cálculo dos índices climáticos como o SPI (Índice de Precipitação Padronizado) e RAI (Índice de Anomalia de chuva). Os índices conseguiram detectar a variação entre anos extremamente úmidos e anos extremamente secos. Destacaram-se os anos 2009 e 2014, sendo que o ano de 2009 representou um ano de anomalia positiva, com precipitação acima da média climatológica. Já em 2014, foi possível detectar uma condição de anomalia negativa, com condições mais severas com precipitação pluvial abaixo da média climatológica. Com a finalidade de avaliar como essa dinâmica climática influencia na dinâmica da vegetação, os índices EVI, LSWI e LAI foram analisa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Climate change causes significant impacts on the structure and distribution of ecosystems affecting terrestrial biodiversity. The objective of the research was to describe the patterns of the dynamics of the natural vegetation of the Atlantic forest in the region of the watershed of Rio Paraíba do Sul (UGRHI 2) and to identify the relationship that is established between climatic variability and vegetation. Image data from temporal series of vegetation indices as the improved Vegetation Index (EVI), Vegetation Humidity Index (LSWI) and foliar area index (LAI) derived from remote sensing products (SR), were acquired from the MODIS sensor, as they are Powerful tools indicating the development of vegetation. Rainfall precipitation data acquired by precipitation stations provided by the National Water Agency (ANA) were applied for calculating climatic indexes such as the Standardized Precipitation Index (SPI) and Rain Anomaly Index (RAI). The indexes were able to detect the variation between extremely humid years and extremely dry years. The years 2009 and 2014 were highlighted, and the year 2009 represented a year of positive anomaly, with precipitation above the average climatological. In 2014, it was possible to detect a negative anomaly condition, with harsher conditions with rainfall precipitation below the climatological average. For the purpose of evaluating how this climate dynamics influences the dynamics of vegetation, the indices EVI, LSWI and LAI were analyzed and sho... (Complete abstract click electronic access below) / Mestre

Spatial planning plays a significant role in enhancing climate change adaptation especially within an urban area. The alignment of spatial planning with climate change adaptation opens an opportunity to improve resilience in areas of high vulnerability and manage the unavoidable. This mini-dissertation examines township spatial planning and climate change adaptation in identifying potentialities for an integrated approach. Therefore, Mdantsane case study as one of the largest townships in South Africa was explored as a unique landscape with reminiscent of apartheid to improve the people’s climate change adaptation under urban poverty, lack of basic facilities and other environmental challenges. In keeping with a case study design, mixed methods were adopted in data collection and analysis making use of GIS and remote sensing techniques alongside pretested open and close-ended questionnaires. The study reveals that townships are extremely susceptible to the impacts of climate change due to their built-up and natural environment set up as well as the existing interrelations. Based on this study major findings, Mdantsane built up cover in year 1996 was 269.496 km2 followed by vegetation area of about 142.272 km2; the area covered by water body was 31.554 km2 while other land surface features cover about 317.277 km2. It was revealed that there was a drastic change in vegetation cover between 1996 and 2016, where built up cover area increased to 375.552 km2 and vegetation cover is 119.277 km2 while water body and other land features cover was about 29.889 and 235.881 km2 respectively. Furthermore, 66 percent of the respondents agreed that agriculture is the predominant land use activity been carried out in the study area, respondents at 74.4 percent affirmed that solid waste and sanitation problems are environmental issues which can lead to climate change over time as a result of the burning of garbage. It is worthy to note that 70 percent of the entire respondents have not participated in any spatial planning process in the past. Thus, comprehensive integration of spatial planning is essential for townships proofing, health, wellbeing and resilience. To this end, the five P’s model (Policy, Public participation, Programme implementation, Political will and Programme monitoring) integration was proposed to seek strategic intervention in sustaining adaptation of local residents to climate change in the future with specific focus to reduce climate and environmental risks in Mdantsane Township.

Climate change has posed significant challenges for the world's sustainable development, and the water cycle is highly dependent on the climate system. In particular, the arid zone fragile ecosystems in northwest China are highly vulnerable to the sophisticated hydrological variations. While ground-based measurements are less capable for large scale hydrological modelling, remote sensing techniques offer enhanced and effective alternatives for various hydrological states/fluxes. With the advancement of the Gravity Recovery and Climate Experiment (GRACE) satellites, the Terrestrial Water Storage (TWS), an integrative measurement of regional hydro-climatic environment, can now be measured as well for examining the overall hydrological response to recent climate change. TWS is an essential element of the water cycle and a key state variable for land surface-atmosphere interaction. Investigating the TWS change is important for understanding the response of the water cycle to climate change. In this study, the intra-annual and inter-annual spatio-temporal change pattern of TWS in Xinjiang Uyghur Autonomous Region of China during 2003-2015 are characterized from Gravity Recovery and Climate Experiment (GRACE) Tellus data products. Sub-regional re-analysis reveals that the increasing/decreasing rate in sub-regions, namely, Altay Mountains (ATM), Junggar Basin (JGB), Tianshan Mountains (TSM), Tarim Basin (TRB) and Kunlun Mountains (KLM), are - 3.41mm, -5.82mm, -6.76mm, -2.59mm and +3.05mm per year in unit of equivalent water height (EWH), respectively. The results suggest that TWS variation presents certain spatio-temporal patterns with spatial heterogeneity. The uncertainties from different GRACE products are also assessed. In conjunction with gridded meteorological data products and land surface model simulations of hydrological variables, the heterogeneous mechanisms of seasonal TWS change are analyzed. The correlation relationship among various hydrologic states/fluxes variables (e.g. snow water, soil water, snow amount) and climatic variables (e.g. temperature and precipitation) with GRACE-derived TWS variation in different sub-regions are investigated. The findings appear to indicate that 1) temperature month-over-month change and temperature anomaly with 4- month time lag, rather than precipitation, are more capable to explain the intra- annual TWS variation; 2) In most part of the study area, the TWS intra-annual change can be primarily attributed to the snow accumulation in winter and melt in spring. On the other hand, the glacier mass variation, which is particularly sensitive to recent climate change, could be a substantial contributor to inter-annual TWS change. The elevation trends over glaciers are estimated based on ICESat altimetry measurements. Correlation analysis results suggest that, during 2003- 2009, the inter-annual TWS loss in Tianshan Mountains (TSM) was tightly associated with glacier mass variation induced by temperature change, particularly in summer. In contrast, TWS gain in Kunlun Mountains (KLM) can be attributed to glacier mass increase. By utilizing remote sensing observation techniques/products, this study has characterized the spatio-temporal change pattern of TWS in northwest arid zone of China, as well as the underlying mechanism. It suggests that TWS is an effective indicator of regional climate change. This study contributes to a better understanding of the hydrologic and climatic processes in arid zone water cycle, and could be beneficial for regional water resources management and climate change adaptation effort.

The focus of this study is on understanding the multiple and interacting factors that hinder or enable municipal planned climate change adaptation, here called barriers and enablers respectively, and their implications for community based adaptation. To do this I developed a conceptual framework of barriers to and enablers of planned climate change adaptation, which informed a systematic literature review of barriers to planned community based adaptation in developing countries. In this framework barriers were grouped into resource, social and physical barriers. I then conducted empirical case study analysis using qualitative research methods in four South African municipalities to understand what barriers and enablers manifested in these contexts. In light of the reflexive nature of my methodology, my framework was adjusted based on my empirical findings, where contextual barriers were found to better represent the empirical results and subsumed physical barriers. I found my framework useful for analysis, but in the empirical cases, barriers and enablers overlaid and interacted so significantly that in reality it was often difficult to separate them. A key finding was that enablers tended to be more about the way things are done, as opposed to direct opposites of barriers. Comparison of barriers and enablers across the case studies revealed a number of key themes. Municipalities struggle to implement climate change adaptation and community based adaptation within contexts of significant social, economic and ecological challenges. These contextual barriers, when combined with certain cognitive barriers, lead to reactive responses. Existing municipal systems and structures make it difficult to enable climate change adaptation, which is inherently cross‐sectoral and messy, and especially community based adaptation that is bottom‐up and participatory. Lack of locally applicable knowledge, funding and human resources were found to be significant resource barriers, and were often underlain by social barriers relating to perceptions, norms, discourses and governance challenges. Enablers of engaged officials, operating within enabling organisational environments and drawing on partnerships and networks, were able to overcome or circumvent these barriers. When these enablers coincided with windows of opportunity that increased the prioritisation of climate change within the municipality, projects with ancillary benefits were often implemented. Analysis of the barriers and enablers identified in the literature and case studies, informed discussion on whether municipalities are able to implement community based adaptation as defined in the literature, as well as the development of recommendations for how municipal planned climate change adaptation and community based adaptation can be further understood and enabled in the future. These recommendations for practice and research include: (a) To acknowledge and understand the conceptual framings of municipal climate change work, as these framings inform the climate change agenda that is pursued, and hence what municipal climate change adaptation work is done and how it was done. (b) The need for further research into the social barriers that influence the vital enablers of engaged officials, enabling organisational environments, and partnerships and networks. (c) To learn from pilot community‐level interventions that have been implemented by municipalities, as well as from other disciplines and municipalities. (d) To develop top‐down/bottom‐up approaches to enable municipal planned climate change adaptation and community based adaptation, that benefits from high level support and guidance, as well as local level flexibility and learning‐by‐doing. (e) To develop viable mechanisms for municipalities to better engage with the communities they serve.

Orientador: Ana Beatriz Lopes de Sousa Jabbour / Banca: Mônica Cavalcanti Sá de Abreu / Banca: Enzo Barbeiro Mariano / Resumo: O objetivo desta pesquisa é entender sob a perspectiva da teoria da contingência, como os fatores contingenciais climáticos e o gerenciamento interno organizacional realizado por um conjunto de empresas podem explicar a percepção de benefícios ao adotar práticas operacionais de baixo carbono. Para atingir este objetivo, o método de pesquisa escolhido foi entrevista, o qual foi conduzido com profissionais de seis empresas dividas em quatro setores industriais diferentes, utilizando para a análise dos dados o software NVivo a fim de entender as percepções dessas empresas estudadas. Os resultados encontrados foram: a) a percepção e o monitoramento de riscos climáticos disparam um gerenciamento interno organizacional mais estruturado pelas empresas; b) as empresas tendem a manter o modelo de gestão ambiental estabelecido para inserir fatores de mudanças climáticas em seus procedimentos; c) uma incipiente estrutura de gerenciamento interno organizacional presente nas empresas afeta suas percepções de benefícios ao adotarem práticas de baixo carbono, mesmo que diversifiquem suas ações; d) o gerenciamento de carbono sob os aspectos contingenciais pode explicar a inação das empresas neste contexto de mudança climática. Com isso, as contribuições deste trabalho consistem em fornecer à literatura evidências empíricas de como se estabelece a relação entre a percepção e o monitoramento de riscos com o gerenciamento de fatores climáticos organizacionais a partir do uso da teoria da contin... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this research is to understand, by the contingency theory perspective, how contingency climate factors and organizational internal factors management can explain the perception of benefits from adoption of low carbon operations practices by a set of enterprises. The research method chosen was interviews with specialists, which were made with professional of six enterprises in four different industries. The NVivo software was used to analyze data from interviews in order to understand the perceptions of those enterprises studied. The results found were: a) the perception and the monitoring of climate risks trigger organizational climate factors management better structured by enterprises; b) enterprises tend to keep the environmental management established to implant climate factors management in their procedures; c) incipient structure of climate factors management stand by in enterprises affect their perceptions of benefits when they have adopted low carbon operations practices, even they have diversified their actions; d) management carbon under contingencies aspects can explain the inaction of the enterprises in the climate change context. Therefore, this research contributes to literature through empirical evidences about how is the relationship between perception and monitoring of climate risks and organizational climate factors management by the perspective of contingency theory. Furthermore, the research contributes to discussion about the effectiveness of t... (Complete abstract click electronic access below) / Mestre

Orientador: Tiago Santana Balbuena / Banca: Gilberto Barbosa Domont / Banca: Pedro Luís da Costa Aguiar Alves / Resumo: A emissão de dióxido de carbono (CO2) pelas atividades humanas vem aumentando desde a revolução industrial. Previsões indicam que ocorrerá um aumento expressivo da concentração atmosférica deste gás nos próximos anos. Este fato deve resultar em alterações metabólicas nas plantas e, por consequência, impactar o setor florestal brasileiro. Os cloroplastos são as organelas-chave na fixação do CO2 e início do particionamento do carbono nas plantas. Alterações na disponibilidade de CO2 podem afetar o metabolismo dessas organelas. O objetivo do presente trabalho foi avaliar se o cultivo de plantas jovens de Eucalyptus urograndis em ambiente enriquecido com CO2 resulta em alterações no proteoma cloroplastidial. Para tanto, primeiramente foram avaliados diferentes métodos de isolamento de cloroplastos quanto aos seguintes parâmetros: morfologia dos cloroplastos observada em microscopia de luz (1); rendimento protéico após isolamento plastidial (2); grau de contaminação por proteínas não cloropastidiais (3); e abundância em número de proteínas identificadas e já descritas como plastidiais (4). Após a definição da melhor metodologia para obtenção do proteoma cloroplastidial, mudas de Eucalyptus urograndis de aproximadamente três meses de idade foram cultivadas sob concentrações atmosféricas controladas de CO2 (400 e 1000 ppm) durante dez semanas. A avaliação do proteoma plastidial, por buscas restringentes contra um banco de dados de sequências protéicas de Eucalyptus grandis, resultou... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Carbon dioxide (CO2) emissions from human activities have increased since the industrial revolution. Global projections indicate that there will be a significant increase in the atmospheric concentration of this gas in the coming years. This fact can result in metabolic changes in plants and, consequently, affect the Brazilian forest sector. Chloroplasts are key organelles in carbon fixation and early carbon partitioning in plants. Changes in the availability of CO2 may affect the metabolism of these organelles. The goal of the present study was to assess whether the cultivation of seedlings of Eucalyptus urograndis under a CO2 enriched environment could result in changes in the chloroplast proteome. For this purpose, different chloroplast isolation methods were evaluated to the following parameters: chloroplast morphology observed in bright-field microscopy (1); protein yield after plastid isolation (2); degree of contamination by non-plastidic proteins (3); and abundance in the number of identified proteins described as plastidic (4). After determining the best methodology for the isolation of the chloroplast proteome, E. urograndis seedlings about three months old were grown under CO2 controlled atmospheric concentrations (400 and 1000 ppm) for ten weeks. Evaluation of the plastid proteome, using stringent search against a protein sequence database from Eucalyptus grandis, resulted in the identification of 816 proteins in E. urograndis, from which 80% were already describe... (Complete abstract click electronic access below) / Mestre

Orientador: Ana Cláudia Ruggieri / Banca: Carlos Eduardo Pellegrino Cerri / Banca: Patrícia Perondi Anchão de Oliveira / Banca: Ricardo Andrade Reis / Banca: Mara Cristina Pessoa da Cruz / Resumo: Metano (CH4) e óxido nitroso (N2O) são dois dos mais importantes gases de efeito estufa emitidos pela pecuária. Eles são produzidos pelas excretas dos animais e fertilizantes. No Brasil, a quantidade emitida destes gases e opções para mitigação foram pouco exploradas. Uma sequência de 4 experimentos foram realizados em campo (em duas estações chuvosas e duas secas, 106 dias de duração cada) com o objetivo de quantificar as emissões de N2O e CH4, volatilização de NH3 e o fator de emissão (FE) quando aplicadas fezes, urina, fezes + urina e fertilizante ureia em Latossolo Vermelho cultivado com capim-marandu. Investigou-se o efeito da umidade do solo e compactação, composição da urina, volume urinário, e adição de fezes sobre as emissões de N2O em um Latossolo recebendo urina manipulada em condições controladas, bem como nas emissões de CH4. Como opção para mitigar as emissões de gases de efeito estufa (GEE) foram estudadas as variáveis como as alturas de pastejo que afetam a magnitude das emissões de GEE; a influência estacional na produção e consumo dos GEE; quais são as variáveis chaves associadas com as emissões de GEE em pastagens de capim-marandu. Adicionalmente, investigou se o efeito dietético dos níveis do sal mineral na concentração de N na urina, o volume urinário, a proporção dos compostos nitrogenados na urina e a concentração de N nas fezes em condições de campo. Os FEs de N2O quantificados diferiram de acordo com a excreta e estação do ano. O FEs foram 2,34%, 4.26% e 3,95% na estação chuvosa e 3.00%, 1.35% e 1.59% na estação seca, respectivamente, para fezes, urina e fezes + urina. O FE do fertilizante ureia foi 0,37%. As emissões médias do CH4 acumuladas foram 99,72, 7,82 e 28,64 (mg C-CH4 m2) para fezes, urina e fezes + urina nesta sequência. Quando manipuladas as condições do solo como umidade, compactação e adição de... / Abstract: CH4 and N2O are two of the most important greenhouse gas emitted by livestock. They are produced from animal excretes and the fertilizer. In Brazil the amount and options to mitigate these gases are little explored. We carried out a sequence of 4 field-trials (two rainy and two dry season, 106 days each) aimed to quantify the N2O and CH4 emissions, NH3 volatilization and emission factor (EF) after application of dung, urine, dung + urine and urea fertilizer on a Ferralsol of a marandu palisade-grass pastureland of Brazil. We aimed to investigate the effects of soil moisture, soil compaction, urine composition, urine volume, and dung addition on N2O emission from a urine-treated tropical Ferralsol under controlled conditions as well on CH4 emission. As option to mitigate greenhouse gas (GHG) emissions we studied how grazing heights affect the magnitude of GHG emissions; how season influence GHG production and consumption; what are the key driving variables associated with GHG emissions. Additionally, we investigated the effect of dietary mineral salt levels on urine-N concentration, urine volume, the proportion of N compounds in the urine and faeces-N concentration under field conditions. The emissions factor (EF) calculated differed according excretes and season. The EFs were 2.34%, 4.26% and 3.95% in the rainy season and 3.00%, 1.35% and 1.59% in the dry season, respectively, for the dung patches, urine patches and dung + urine. The N2O EF from urea was 0.37%. The averages of CH4 accumulated emissions were 99.72, 7.82 and 28.64 (mg CH4-C m2) for dung, urine and dung + urine in this sequence. The manipulated soil conditions moisture content, compaction, and dung addition affected N2O emissions when varying quantities of urine-N were applied (in equal urine volumes) being higher when added dung and did not affect when varying urine volumes were applied (containing equal quantities of urine-N) ... / Doutor

Orientador: Iandara Alves Mendes / Banca: Regina Célia de Oliveira / Banca: Cenira Maria Lupinacci da Cunha / Resumo: A Bacia do Ribeirão dos Poncianos, situada na região ocidental da Serra da Mantiqueira, porção Mineira. Na área são evidenciados controles estruturais que influenciam a drenagem e a disposição do relevo, bem como os depósitos fluviais encontrados na área. Estes fenômenos puderam ser comprovados pela análise dos dados morfométricos gerados nesta pesquisa. Além dos controles estruturais, também foram estudados materiais sedimentares que estruturam os colúvios existentes em algumas vertentes da área de estudo. Estes colúvios localizam-se a setores da vertente de anfiteatro suspenso desarticulado do nível de base atual e anfiteatro articulado ao nível de base. A análise das amostras destes materiais coluviais e das datas obtidas para estes indicam que são fruto de mudanças climáticas que ocorreram durante o Pleistoceno Superior. Suas origens estão vinculadas a movimentos gravitacionais lentos (colúvios) e soterramento de material vegetal (Turfeiras), os limites entre estes se fazem na forma de discordância erosiva e deposicional. Os materiais encontrados apresentam características diferenciadas o que proporcionou através de sua análise atribuir-lhes como sendo fruto de flutuação climáticas ocorridas no período Quaternário. / Abstract: The Basin of Ribeirão dos Poncianos, located on ocidental Serra da Mantiqueira, Minas Gerais side. The area show evidences of structural controls on drainage, relief and, fluvial deposits. This process could be proved by the analysis of morphometrical data produced in this research. Moreover the structural controls, also studied the sedimentary materials that structured the coluvium that appear in some slopes on the area. This colluvials material is located in sectors of slope of hollows unlinked to current base level and hollow linked to base level. The analyses of colluvial samples and the ages of this materials indicate that is consequence of climatic changes that occur during Upper Pleistocene. The materials origin its linked to gravitational slow movements (colluvium) and buried organic materials (peat), the limits between this materials is made by erosive and depositional discordance. The materials founded show differentiated characteristics that provided by the analysis to attribute than like a results of climatic changes occurred at Quaternary period. / Mestre

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Melon is one of the most economically important crops and increasing exports in the Brazilian Northeast region. Since most of the Brazilian melon is grown in the semiarid region and depends entirely on irrigation, it is likely that climate changes underway will have significant impacts on the crop water demand and on water resources of the main producing regions. The present study aimed at analyzing the possible impacts of climate change on water requirement of the melon crop, considering two climate change scenarios, applied on a local scale. The study covered the main producing region of melon in Brazil, formed by subregions Mossorà and AÃu, in state of Rio Grande do Norte state and Lower Jaguaribe in the state of CearÃ. It was used the system PRECIS (Providing Regional Climates for Impact Studies), with the regional climate model HadRM3P of the Hadley Centre. In applying the model we used a data set consisting of a baseline (basic climatology) for the period 1961 to 1990 and projections of future climate, for the year 2040, for the climate change scenarios A2 and B2. To interpolate the climatic variables for the geographic coordinates of the study area it was used a geographic information system (GIS) ARCGIS 9.3Â. Bearing in mind the crop season in the region, three crop cycles were considered (July to September, September to November, November to January). Reference evapotranspiration was estimated by FAO Penman-Monteith method with minimal data. Projections of climate change were mapped and showed elevations of average reference evapotranspiration of 6.2% and 7.6%, and reductions in rainfall of 38.3% and 55.9%, in the scenarios A2 and B2, respectively, at regional level. It was estimated a rise in average gross water requirement of 8.7% and 10.5% for the year 2040, in the scenarios A2 and B2, respectively. / O meloeiro à uma das horÂtaliÃas de maior importÃncia econÃmica e de maior crescimento nas exportaÃÃes na regiÃo Nordeste do Brasil. Como a maior parte da produÃÃo brasileira de melÃo ocorre na regiÃo semiÃrida e depende totalmente da irrigaÃÃo, à provÃvel que as mudanÃas climÃticas em curso tenham impactos significativos sobre a demanda hÃdrica da cultura e sobre os recursos hÃdricos das principais regiÃes produtoras. O presente estudo foi desenvolvido com o objetivo de analisar os possÃveis impactos das mudanÃas climÃticas na necessidade hÃdrica da cultura do melÃo, considerando dois cenÃrios de mudanÃas climÃticas, aplicados em escala local. O estudo abrangeu a principal regiÃo produtora de melÃo no Brasil, formada pelo Agropolo de Mossorà e AÃuâRN e o Agropolo do Baixo Jaguaribe-CE. Utilizou-se o sistema PRECIS (Providing Regional Climates for Impact Studies), empregando-se o modelo climÃtico regional HadRM3P do Hadley Centre. Na aplicaÃÃo do modelo foi utilizado um conjunto de dados composto de uma baseline (climatologia de base) do perÃodo de 1961 a 1990 e de projeÃÃes climÃticas futuras, para o ano de 2040, nos cenÃrios de mudanÃas climÃticas A2 e B2. Para interpolar as variÃveis climÃticas das coordenadas geogrÃficas da regiÃo em estudo foi empregado o sistema de informaÃÃes geogrÃfica (SIG) ARCGIS 9.3Â. Tendo por base o perÃodo em que se planta melÃo irrigado na regiÃo, consideraram-se trÃs ciclos de cultivo (1 de julho a 5 de setembro, 1 de setembro a 5 de novembro, 1 de novembro a 5 de janeiro). A evapotranspiraÃÃo de referÃncia foi estimada pelo mÃtodo Penman-Monteith FAO com dados mÃnimos. As projeÃÃes das mudanÃas climÃticas foram mapeadas e mostraram elevaÃÃes mÃdias da evapotranspiraÃÃo de referÃncia de 6,2% e 7,6%, e diminuiÃÃo da precipitaÃÃo pluviomÃtrica de 38,3% e 55,9% nos cenÃrios A2 e B2, respectivamente, a nÃvel regional. Foi estimada uma elevaÃÃo da necessidade hÃdrica bruta mÃdia de 8,7% e 10,5% para o ano de 2040, nos cenÃrios A2 e B2, respectivamente.