Conventional fossil fuels are widely used, however there are growing concerns about the security of their supply, volatility in their prices and the environmental impacts of their extraction and use. The objective of this research is to investigate the potential for replacing conventional fuels in various applications, focusing on the Alberta oil sands industry. Such investigations require systems-level approaches able to handle multiple criteria, uncertainty, and the views of multiple stakeholders. To address this need, the following are developed: life cycle assessment (LCA) and life cycle costing models of polygeneration systems; a life cycle-based framework for multi-sectoral resource use decisions; and a method combining LCA and real options analyses to yield environmental and financial insights into projects. These tools are applied to options for utilizing oil sands outputs, both the petroleum resource (bitumen) and by-products of its processing (e.g., asphaltenes, coke), within the oil sands industry and across other sectors. For oil sands on-site use, multiple fuels are assessed for the polygeneration of electricity, steam and hydrogen, in terms of life cycle environmental and financial impacts; asphaltenes gasification with carbon capture and storage (CCS) is the most promising option, able to reduce greenhouse gas (GHG) emissions to 25% of those of current natural gas-based systems. Coke management options are assessed with the life cycle-based framework; the most promising options are identified as: Electricity generation in China through integrated gasification combined cycle; and, hydrogen production in Alberta, either for sale or use by the oil sands industry. Without CCS, these options have amortized project values ranging from $21 to $160/t coke. The application of the combined LCA and real options analyses method finds that uncertainty in natural gas and potential carbon prices over time significantly impacts decisions on coke management; the formulated decision tree identifies increases of 29% and 11% in the financial and GHG emissions performance, respectively, of the overall coke management project compared to pursuing the decision identified by the life cycle-based framework. While promising options for replacing conventional fossil fuels are identified through systems-level analyses, there are trade-offs to be made among the financial, risk and environmental criteria.

One of the largest environmental threats believed to be facing us today is global warming due to the accumulation of green house gases (GHG). The concentrations of GHG in the atmosphere are a result of the net strength of different sinks and sources. Forests, in this context, are of particular interest because of their dual role as both sinks and sources. Most forests are net sinks for CO2 but others, such as drained forests, may be significant sources of both CO2 and N20. Consequently, it is essential to understand the fluxes of GHG between drained forests and the atmosphere in order to obtain accurate estimates of national GHG budgets. The findings reported in this thesis and the accompanying papers are based on dark chamber flux measurements of soil GHG fluxes and modelled annual net primary productions in five drained forest sites and two undrained sites situated on organic soil. Temporal variations in forest floor CO2, release could be explained, to a large extent, by differencies in temperature and groundwater level. The within-site spatial variation in soil GHG fluxes could only be explained to a very small extent by distance to tree stems. Much of the among-site variations in soil CO2 and CH4 release could be caused by differences in the mean annual groundwater table, while N20 emissions were strongly correlated to the carbon-to-nitrogen ratio of soil organic matter. Most poorly drained forested areas are probably net sinks for GHG as the CO2 uptake by trees more than compensates for the soil GHG emissions. However, the total drained forested area in Sweden was estimated to be a net source of GHG. The CO2 release from decomposition of soil organic matter stored before drainage was estimated to be substantial. Corresponding to 15% of the CO2 release from the consumption of fossil fuels. / <p>On the day of the public defence of the doctoral thesis the status of the articles I and II was: Conditionally accepted; article III was: Submitted and articles IV and V was: Manuscript. The title of article III was on the day of the public defence "Can the distribution of trees explain the spatial variation in N2O emissions from boreal forest soils?".</p>

Los suelos de los bosques tropicales desempeñan un papel importante en el clima de la Tierra mediante el intercambio con la atmosfera de grandes cantidades de gases de efecto invernadero (GEI). Sin embargo, esta importante función podría ser alterada por las actividades humanas causando el aumento en la deposición de nutrientes en los ecosistemas terrestres, especialmente en las regiones tropicales. Las causas de cómo el incremento de las cantidades de nutrientes está afectando los flujos de suelo de los GEI de los bosques tropicales es relativamente poco conocida, por ello los monitoreos de nutrientes in situ de los bosques montanos tropicales (BHT) son aún menos comprendidos. Ya que los BHT representan alrededor del 11-21% de la superficie forestal tropical, es de vital importancia predecir y cuantificar los cambios en los flujos de GEI del suelo en respuesta a la adición de nutrientes ya que podrían favorecer la retroalimentación a otros cambios globales. Esta tesis tiene como objetivo cuantificar el impacto de adición moderada de nitrógeno (N) y/o fósforo (P) en los flujos de tres GEI en suelo: dióxido de carbono (CO2), óxido nitroso (N2O) y el metano (CH4), a lo largo de un gradiente altitudinal (1000 m, 2000 m, 3000 m) de los BHT primarios en el sur de Ecuador. Desde hace más de cinco años, se ha medido los flujos de GEI del suelo en un experimento de manipulación de nutrientes (‘NUMEX’, por sus siglas en inglés), con replicas para control, y la adición de N (50 kg N ha-1 año-1), P (10 kg P ha-1 año-1) y N+P. Las mediciones in situ se realizaron mensualmente utilizando cámaras ventiladas estáticas, seguido por un análisis de cromatografía de gases para conseguir una perspectiva más profunda sobre los procesos implicados en el intercambio suelo-atmósfera de GEI. Se realizaron nuevas investigaciones incluyendo el monitoreo de factores básicos de control (i.e. temperatura del suelo, humedad y las concentraciones del N mineral), los diferentes componentes de los flujos de CO2 del suelo, tasas de reciclaje netos de N y fuentes de los flujos de N2O del suelo. Con este propósito, se utilizó la extracción de hojarasca y técnicas de excavación de zanjas (trenching technique), incubación de las muestras in situ (buried bag method) y el etiquetaje de 15N de corto plazo. Los flujos de GEI del suelo en los bosques que estudiados se mostraron en el rango de aceptado de los flujos de gases de otras BHT en elevaciones comparables, excepto para el N2O. Los flujos de N2O, que se derivan principalmente de la des nitrificación, fueron bajos para un TMF lo que se puede atribuir a los ciclos conservativos de N del suelo en nuestros sitios de estudios. Los suelos fueron fuentes de CO2 y N2O (la intensidad del recurso disminuye al aumentar la altitud) y en todas las elevaciones el CH4 es bajo. Encontramos efectos de los nutrientes en todos los flujos de GEI medidos en cada elevación. Las respuestas de los flujos de CO2 del suelo cambian con la duración y el tipo de nutrientes adicionado. En 1000 m, la adición del N no afecta los flujos de CO2 del suelo, mientras que las adiciones de P y N+P disminuyeron los flujos en el primer y cuarto a quinto año. En 2000 m., la adición de N y N+P incrementa los flujos de CO2 en el primer año; a partir de entonces, la adición del N disminuye los flujos mientras que la adición de N + P no mostro ningún efecto la adición de P carece de efectos. En 3000 m, la adición de N además incrementó los flujos de CO2 constantemente; la adición de P y N+P aumentaron los flujos sólo en el primer año a partir de entonces no existió ningún efecto. Los efectos diferenciales de los nutrientes estuvieron relacionados a un estatus del N y P y respuestas variadas de los componentes de la respiración del suelo. Las respuestas de los flujos de N2O y CH4 a la adición de nutrientes mostraron gran variabilidad entre años. Los flujos de N2O no se vieron afectados por la adición de tres a cinco años de N a pesar de las diferencias significativas observadas durante los dos primeros años del mismo experimento. Atribuimos la ausencia de las respuestas en años mas tardíos debido a los contenidos bajos de humedad del suelo en nuestro periodo de monitoreo 2010-2012. En todo el gradiente altitudinal, la adición de P disminuyó los flujos de N2O y las concentraciones de N mineral, presumiblemente debido a que alivió de la limitación del P en la producción primaria neta, lo que aumentó la captación de N a través de las plantas. La adición de N+P además mostró tendencias similares las respuestas a la adición de N solamente, pero con efectos menos fuertes debido a los efectos contrapuestos de la adición de P. Durante los dos primeros años de la adición de nutrientes, los flujos de CH4 no se vieron afectados en ninguna elevación, lo cual atribuimos a la combinación de cantidades moderadas de nutrientes añadidos, la fuerte inmovilización de nutrientes, y la separación de la más alta capacidad de absorción de CH4 en el subsuelo de la superficie del suelo donde se añaden fertilizantes. En el tercer a quinto año, la adición de nutrientes del suelo aumentaron la captación de CH4, aunque los efectos de N y P variaron a lo largo del gradiente altitudinal: en 1000 m, la adición de N y N+P aumentó la captación anual de CH4 a 20-60%; en 2000 m P y N+P incrementaron la captación a 21-50%; y en 3000 m la adición de P y N+P incrementó la captación de CH4 a 34-40%. Estos efectos diferenciales de la adición de nutrientes pueden estar relacionados con el estatus inicial de del suelo y respuesta diferenciales de otros componentes del ecosistema a la adición de nutrientes en cada elevación. Demostramos que los flujos de GEI del suelo y consecuentemente la red potencial de calentamiento global del suelo pueden cambiar considerablemente a lo largo de un gradiente de elevación, siguiendo una tendencia general de disminución con el aumento de la elevación. Los resultados indican además que la elevada deposición de N y P puede afectar los flujos de GEI del suelo en los BHT Andinos, pero las respuestas a los flujos de GEI a la adición de nutrientes depende del estatus inicial de los nutrientes del suelo, la duración de la adición de nutrientes y la variabilidad inter-anual de las condiciones climáticas. Puesto que los efectos de la adición de nutrientes fueron no lineares con el tiempo de exposición y a la par existen complejas interacciones con otros componentes del ecosistema, aún quedan muchas incertidumbres en la predicción exacta de los efectos de la deposición de nutrientes en los flujos de GEI. Sin embargo, ofrecemos los primeros datos sobre los efectos de nutrientes a medio plazo de N, P y N+P en los flujos de los tres principales gases de efecto invernadero del suelo a lo largo de un gradiente altitudinal de los BHT Andina. Nuestros resultados sugieren que la red potencial de calentamiento global de los suelos en todo el gradiente altitudinal podría aumentar ligeramente con la entrada contribución de N, mientras que podría disminuir con el aumento de la contribución de P y N+P.

Climate change is a critical sustainable development issue with implications for the environment, economies and society as we know it. The problem of climate change is caused by some countries in parts of the world that has a direct effect on people and natural resources in other parts of the world. Climate change is the effect of increased production of Greenhouse gases (GHGs). Due to the vast complexity of the climate change regime the study does not attempt to be comprehensive or conclusive. The aim of the study is to critically evaluate and determine the purpose, enforceability, legal nature, shortcomings and strengths of the non-binding Copenhagen Accord and how the international climate change regime will evolve after the Copenhagen Accord. The study starts with a brief explanation of the international climate change regime and its development, including international environmental law principles, specifically the common but differentiated responsibility principle. The United Nations Framework Convention on Climate Change (UNFCCC) has the ultimate objective to achieve the stabilisation of GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The Conference of the Parties (COPs) is the ultimate decision-making and supreme body of the UNFCCC and is authorised to make and implement decisions to promote the implementation of the UNFCCC, it further has the power to adopt new protocols under the UNFCCC and plays a substantial role in the development of new obligations by the parties to the convention. Various COPs, their respective adopted decisions and resolutions which played an important role in the development of the climate change regime are discussed. This includes COP 1 that lead to the Berlin Mandate; COP 3 and the Kyoto Protocol; COP 7 and the Marrakech Accords; COP 11 that marked the entry into force of the Kyoto Protocol; COP 13 and the Bali Action Plan. COP 15 in Copenhagen was internationally expected and intended to be the breakthrough in addressing the post 2012 period. As is evident from the content of this study the result of COP 15 at Copenhagen means different challenges for different countries and the “bottom up” architecture of the accord could help encourage and reinforce national actions. An overview of the effect of the Copenhagen Accord on the climate change regime, with specific reference to COP 16 in Cancun, is then done. The “bottom up” architecture of the Copenhagen Accord was brought into the official UNFCCC process by the Cancun Agreements that were reached at COP 16. The study mostly comprised of a literature study, which reviewed the relevant international environmental law dealing with climate change, taking into account customary international law; international treaties and conventions; government documents, policies and reports; textbooks and academic journals as well as electronic material obtained from various internet sources. / Thesis (LLM (Environmental Law and Governance))--North-West University, Potchefstroom Campus, 2012

Climate change is a critical sustainable development issue with implications for the environment, economies and society as we know it. The problem of climate change is caused by some countries in parts of the world that has a direct effect on people and natural resources in other parts of the world. Climate change is the effect of increased production of Greenhouse gases (GHGs). Due to the vast complexity of the climate change regime the study does not attempt to be comprehensive or conclusive. The aim of the study is to critically evaluate and determine the purpose, enforceability, legal nature, shortcomings and strengths of the non-binding Copenhagen Accord and how the international climate change regime will evolve after the Copenhagen Accord. The study starts with a brief explanation of the international climate change regime and its development, including international environmental law principles, specifically the common but differentiated responsibility principle. The United Nations Framework Convention on Climate Change (UNFCCC) has the ultimate objective to achieve the stabilisation of GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The Conference of the Parties (COPs) is the ultimate decision-making and supreme body of the UNFCCC and is authorised to make and implement decisions to promote the implementation of the UNFCCC, it further has the power to adopt new protocols under the UNFCCC and plays a substantial role in the development of new obligations by the parties to the convention. Various COPs, their respective adopted decisions and resolutions which played an important role in the development of the climate change regime are discussed. This includes COP 1 that lead to the Berlin Mandate; COP 3 and the Kyoto Protocol; COP 7 and the Marrakech Accords; COP 11 that marked the entry into force of the Kyoto Protocol; COP 13 and the Bali Action Plan. COP 15 in Copenhagen was internationally expected and intended to be the breakthrough in addressing the post 2012 period. As is evident from the content of this study the result of COP 15 at Copenhagen means different challenges for different countries and the “bottom up” architecture of the accord could help encourage and reinforce national actions. An overview of the effect of the Copenhagen Accord on the climate change regime, with specific reference to COP 16 in Cancun, is then done. The “bottom up” architecture of the Copenhagen Accord was brought into the official UNFCCC process by the Cancun Agreements that were reached at COP 16. The study mostly comprised of a literature study, which reviewed the relevant international environmental law dealing with climate change, taking into account customary international law; international treaties and conventions; government documents, policies and reports; textbooks and academic journals as well as electronic material obtained from various internet sources. / Thesis (LLM (Environmental Law and Governance))--North-West University, Potchefstroom Campus, 2012

No description available.

Intercropping, defined as two or more crops grown on the same land area at the same time, is a sustainable alternative to sole crops. Intercropping has been associated with multiple benefits, such as increased nutrient and soil organic carbon (SOC) cycling, decreased soil erosion and increased carbon (C) sequestration. A common intercropping practice is to integrate cereal and legume crops such as maize (Zea mays L.), and soybean (Glycine max (L.) Merr.). Most studies on intercropping have focused on yield, weed control, and land use efficiency in the tropics. Few studies have researched C and nitrogen (N) dynamics in temperate intercrops, with respect to soybean and maize residue stabilization. Soil from Balcarce, Argentina, was incubated for 140 days with soybean, maize, or no residue. Throughout the incubation, results illustrated the effect of residue application upon the soil, specifically through significantly higher amounts of light fraction (LF) C and LFN concentrations, soil microbial biomass (SMB) C and SMBN concentrations, higher microbial diversity, lower N2O production rates, in addition to distinct isotopic values in soil fractions and CO2 (p<0.05). Furthermore, it was observed from δ15N-TN and δ15N-LF that treatments with soybean residues included had higher N cycling (p<0.05), emphasizing the importance of including N-fixing legumes in complex agroecosystems. Significant changes over time in SMB and SMCS characteristics, and isotope values (p<0.05) indicated the preferential utilization of relatively young and easily accessible litter. Furthermore, the loss of labile material over the incubation resulted in more recalcitrant forms (such as older C and lignin) to be utilized. Slightly higher SOC, TN, LFC and LFN concentrations, as well as lower CO2 production rates suggested 2:3 (rows of maize:rows of soybean) as a more desirable intercrop design for C sequestration. The 1:2 intercrop design was observed to be more beneficial for microbial community structure, furthering the idea that intercropping is a beneficial alternative to sole cropping. This study improves knowledge in residue stabilization and C sequestration in complex agroecosystems, providing encouragement for the implementation of more sustainable management practices.

CNPq; Fundação Araucária / A região do Sudoeste do Paraná apresenta o setor agrário bem desenvolvido, com ênfase na produção leiteira de pela agricultura familiar. A base nutricional dessas propriedades são as pastagens formadas por gramíneas tropicais, as quais apresentam uma diminuição em sua produção de fitomassa em determinada época do ano, com a queda na intensidade luminosa e temperatura. A implantação de pastagens temperadas, principalmente de aveia, é uma estratégia comum na região para a atividade. Avaliou-se os efeitos dos níveis de nitrogênio no crescimento, desenvolvimento, acúmulo de fitomassa, composição química, cinética ruminal e produção de gases de efeito estufa. O trabalho foi conduzido na UTFPR-DV nos anos de 2013 e 2014, em blocos ao acaso com quatro níveis de adubação N (0,60, 120 e 240 KgN.ha-1) com 3 repetições, em períodos de corte a cada 21 dias, usando-se cultivares de aveia branca (Avena sativa L.) URS Guapa e IPR126. Foram analisados taxa de assimilação de CO2, concentração intracelular de CO2, taxa de transpiração, temperatura da folha, teor de clorofila, produção de fitomassa, proteína, FDN, lignina, EE, produção de gás em relação aos teores de carboidratos de rápida degradação e de degradação lenta, bem como CH4, CO2 e N2O.Para IPR 126 no ano de 2013 houve efeito significativo nas variáveis PB, CT, k1, eficiência do uso da água, transpiração e temperatura foliar, enquanto que para o ano de 2014, as variáveis foram CT, vf1, k1, vf2, número de perfilhos e eficiência do uso da água. Para a cultivar URS Guapa, no ano de 2013, houve efeito significativo para as variáveis peso das folhas (em gramas) e temperatura foliar, enquanto que no ano de 2014, número de perfilhos, transpiração e temperatura foliar foram significativos.Observou-se que a cultivar IPR 126 foi mais influenciada pelos níveis de adubação que a cultivar URS Guapa, em todos os anos e os gases de efeito estufa não foram afetados. / The Southwest region of Paraná presents the well-developed agrarian sector, with emphasis on dairy production from family farming. The nutritional base of these properties are pastures formed by tropical grasses, which present a decrease in their phytomass production at a given time of year, with the decrease in luminous intensity and temperature. The implementation of temperate pastures, mainly of oats, is a common strategy in the region for the activity. The effects of nitrogen levels on growth, development, phytomass accumulation, chemical composition, ruminal kinetics and greenhouse gas production were evaluated. The work was conducted in UTFPR-DV in the years of 2013 and 2014, in randomized blocks with four levels of N fertilization (0.60, 120 and 240 KgN.ha-1) with 3 replications, in cut-off times every 21 Days, using white oats (Avena sativa L.) URS Guapa and IPR126. Were analysed CO2 assimilation rates, intracellular CO 2 concentration, transpiration rate, leaf temperature, chlorophyll content, phytomass production, protein, NDF, lignin, EE, gas production in relation to fast-degraded carbohydrate. In the year of 2013, there was a significant effect on the variables PB, CT, k1, water use efficiency, transpiration and foliar temperature, while for the year 2014, Variables were CT, vf1, k1, vf2, number of tillers and water use efficiency. For the cultivar URS Guapa, in the year 2013, there was a significant effect for the variables leaf weight (in grams) and leaf tempreture, while in the year 2014, number of tillers, transpiration and leaf temperartura were significant. It was observed that The cultivar IPR 126 was more influenced by levels of fertilization than the cultivar URS Guapa, in all years and greenhouse gases were not affected.

Este trabalho tem por objetivo avaliar a viabilidade técnica de processos de separação de gás carbônico em correntes de gases de combustão. Neste sentido, a separação por meio de membranas e por criogenia são avaliadas por meio de simulação de sistemas. As propostas envolvendo membranas avaliam arranjos de membranas em série, os quais são otimizados para condições de maior fluxo permeado e maior beneficio econômico. A corrente de alimentação é de 5 kmol/s e as respectivas frações molares de CO2 e N2 que compõem esta corrente são 0,15 e 0,85. Os resultados obtidos da otimização, para um arranjo de três membranas em série de polyimida de 9000 m² de área superficial, foram uma corrente de permeado de 443,1 mol/s de CO2 a 41,6%, correspondendo a aproximadamente 59% do CO2 da corrente de alimentação. Já com um arranjo de 6 membranas de 9000 m², onde a função objetivo é o maior lucro, foi selecionado o material kapton e a quantidade de CO2 separada é 161,12 mol/s, cuja concentração na mistura é de 79%, e a função objetivo tem um valor de 24.405,30 €/ano. Na outra parte do trabalho, propõe-se e avalia-se um ciclo para o aproveitamento da disponibilidade térmica na regasificação do gás natural líquido, para liquefação de CO2. Obtém-se como resultando em CO2 líquido com fração molar igual a 94%. Este processo consta de uma corrente proveniente da combustão completa de 1 mol/s de metano, contendo 1 mol/s de CO2 e 7,52 mol/s de N2. Esta corrente é comprimida e resfriada até atingir a pressão de 4000 kPa e 25 °C, posteriormente uma membrana enriquece a corrente de gases de combustão, que novamente é comprimida e resfriada até se obter a condensação e separação do CO2. Realiza-se o cálculo de equilíbrio líquido-vapor da mistura utilizando as equações de Peng-Robinson e a regra de mistura de Van der Waals no software VRTherm. A vazão molar do CO2 líquido obtida é de 0,3207 mol/s na concentração declarada. A intensidade energética do processo é de 1,135 kWh/kg de CO2 liquefeito. / The objective of this work is to evaluate the technical feasibility of carbon dioxide separation processes of flue gases streams. In this way, separation processes due membrane and cryogenics are evaluated by system simulation. The systems using membranes evaluates setup of those membranes in series, these setups are optimized for the largest permeate molar flow and the largest economic profit. The feed stream is a 5 kmol/s CO2 – N2 mixture, with molar fraction of 0.15 and 0.85 respectively. The result obtained from the optimization for a setup of three polyimide membranes of 9000 m² is a permeate stream of 443.1 mol/s with CO2 at 41.6%, corresponding to aproximadely 59% of the CO2 contained in the feed stream. When a setup of six 9000 m² membranes is analyzed using an objective function that results in the largest profit, kapton was selected as the material for the membranes. The quantity of CO2 captured is 161.12 mol/s, at 79% of concentration in the mixture, and the objective function has a value of 24,405.30 €/year. The second part of this work, proposes and evaluates a cycle that takes the thermal availability of the regasification of liquid natural gas in advantage for CO2 liquefaction. The product of the cycle is liquid CO2, with a molar fraction of 0.94. The process is fed with a stream that comes from the stoichiometric combustion of 1 mol/s of methane, that stream is composed by 1 mol/s of CO2 and 7.52 mol/s of N2. The stream is then compressed up to the pressure of 4000 kPa and cooled down to 25 °C. After that a membrane concentrates the CO2 in one stream, which is again compressed and cooled down until the condensation of CO2 is achieved. Calculations of liquid – vapor are performed with the Peng- Robinson’s equations and the Van der Waals mixture rule using the software VRTherm. The molar flow rate of liquid CO2 obtained is of 0.3207 mol/s in the concentration mentioned before. The energy intensity of the process is of 1.135 kWh/kg of liquid CO2.

Made available in DSpace on 2016-08-12T19:18:36Z (GMT). No. of bitstreams: 1 VivianeSB_TESE.pdf: 3169033 bytes, checksum: 502e3e06c40421e419b1e2cd13178f58 (MD5) Previous issue date: 2015-10-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study evaluates the environmental impact of melon production systems on climate change, integrating the research lines of the Brazilian Agricultural Research Corporation (Embrapa). It is the result of partnership held among Embrapa - Tropical Agroindustry, the Federal Rural University of Semi-Arid (UFERSA), and the University of Massachusetts (UMass). The research is based on an evaluation of the product life cycle (melon), focusing on climate change impact category. The study was conducted in two stages, one held in Brazil, in 2011, and the second, in the US, between 2014 and 2015. In Brazil, data were collected in the experimental area located in Agricola Famosa farm, located in the municipality of Tibau, RN, with order to determine the efficiency of farming systems practiced today (conventional) and conservation, based on the use of green manure. In the conventional system, the melon (Goldex) was cultivated after the merger of spontaneous vegetation and conservation system, after overturning or incorporation of plant biomass from the green manure with maize intercropped with braquiária and Guandu beans. The product system refers to melon production in Brazil covered production in conventional and conservation systems considering the following processes: production of green fertilizers seeds and melon, biomass production of green manure production melon seedlings production melon field, packaging and transport of melons to Europe, as well as production and transportation of supplies for the experimental area. The stage of the research conducted in the United States sought to determine the conventional cultivation system efficiency currently practiced in the experimental farm of UMass. Thus, this product system included the production of seeds and melon seedlings production in melon field, packaging and transport of melon, production and transport of inputs for the experimental area of UMass. In Brazil, the best result of carbon footprint was the conservationist corn intercropping system with braquiária with incorporation that generates an average carbon footprint of 647.82 CO2-eq / t melon, while the footprint of Brazilian conventional system is 756, 90 kg CO2-eq / t. Detailing the process, we observe that the change of land use and melon transportation Port of Pecém, CE, to the port of Rotterdam, in the Netherlands, are the processes that most contribute to the carbon footprint of melon produced in Brazil. The change of land use, due to the increasing number productive melon areas in Northeast Brazil, including Jaguaribe-Açu polo, we consider the emissions for the transformation of land with scrub vegetation to melon producing area. In the US, the footprint is 356 kg CO2-eq/t, and the packaging process is the largest contributor to this result. It is important to note that the land use change impact was not considered in the US, because this change has occurred more than 20 years ago on the farm UMass. We conclude that in terms of environmental efficiency, the best result in Brazil occurs in the conservation system, showing that green manure increases soil organic matter, thus reducing the carbon footprint. In order to reduce the footprint of Brazilian melons, making it as competitive as the US, it is necessary to held to melon production in agricultural areas with natural vegetation removed for more than 20 years before. The results of this research subsidize actions to improve the competitiveness of Brazilian melons front of potential non-tariff barriers related to reducing emissions of greenhouse gases by agriculture and adoption of low carbon practices / Esse estudo avalia o impacto ambiental de sistemas de produção de melão sobre as mudanças climáticas, integrando as linhas de pesquisa da Empresa Brasileira de Pesquisa Agropecuária (Embrapa). É resultado de parceria realizada entre a Embrapa - Agroindústria Tropical, a Universidade Federal Rural do Semi-Árido (UFERSA), e a University of Massachusetts (UMass). A pesquisa é baseada na avaliação do ciclo de vida do produto (melão), com foco na categoria de impacto Mudança Climática. O trabalho foi realizado em duas etapas, uma realizada no Brasil, em 2011, e a segunda, nos EUA, entre 2014 e 2015. No Brasil, dados foram coletados na área experimental localizada na fazenda Agrícola Famosa, situada no município de Tibau-RN, com o objetivo de determinar a eficiência de sistemas de cultivo atualmente praticados (convencional) e conservacionistas, fundamentados no uso de adubação verde. No sistema convencional, o melão (Goldex) foi cultivado após a incorporação da vegetação espontânea, e no sistema conservacionista, após o tombamento ou incorporação da biomassa vegetal proveniente dos adubos verdes milho consorciado com braquiária e feijão guandu. O sistema de produto referente à produção de melão no Brasil abrangeu a produção em sistemas convencional e conservacionistas, considerando os seguintes processos: produção de sementes de adubos verdes e de melão, produção da biomassa de adubo verde, produção de mudas de melão, produção em campo de melão, embalagem e transporte do melão à Europa, bem como produção e transporte dos insumos para a área experimental. A etapa da pesquisa realizada nos Estados Unidos buscou determinar a eficiência do sistema de cultivo convencional atualmente praticado na fazenda experimental da UMass. Assim, esse sistema de produto abrangeu a produção de sementes e mudas de melão, produção em campo de melão, embalagem e transporte do melão, produção e transporte dos insumos para a área experimental da UMass. No Brasil, o melhor resultado de pegada de carbono foi do sistema conservacionista milho consorciado com braquiária com incorporação que gera uma pegada de carbono média de 647,82CO2-eq/t de melão, ao passo que a pegada do sistema convencional brasileiro é de 756,90 kg CO2-eq/t. No detalhamento dos processos, observa-se que a mudança do uso da terra e o transporte do melão do Porto do Pecém, CE, para o porto de Roterdam, na Holanda, são os processos que mais contribuem para a pegada de carbono do melão produzido no Brasil. Na mudança do uso da terra, devido ao crescente aumento de áreas produtoras de melão no Nordeste Brasileiro, incluindo o polo Jaguaribe-Açu, consideram-se as emissões referentes à transformação da terra com vegetação de caatinga para área produtora de melão. Nos EUA, a pegada é de 356 kg CO2-eq/t, sendo o processo de embalagem o que mais contribui com esse resultado. É importante salientar que o impacto da mudança do uso da terra não foi considerado nos EUA, em virtude de essa mudança ter ocorrido há mais de 20 anos na fazenda UMass. Conclui-se que, em termos de eficiência ambiental, o melhor resultado no Brasil ocorre no sistema conservacionista, demonstrando que a adubação verde incrementa a matéria orgânica no solo, reduzindo, consequentemente, a pegada de carbono. Para reduzir a pegada do melão brasileiro, tornando-o tão competitivo quanto o americano, deve-se realizar a produção de melão em áreas agrícolas com vegetação natural removida há mais de 20 anos. Os resultados desse trabalho subsidiam ações visando à melhoria da competitividade do melão brasileiro frente às potenciais barreiras não tarifárias relacionadas à redução das emissões de gases de efeito estufa pela agricultura e adoção de práticas de baixo carbono