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Treballs Finals del Màster d'Economia, Facultat d'Economia i Empresa, Universitat de Barcelona. Curs: 2021-2022, Tutor: Josep Maria Izquierdo Aznar; Pedro Calleja Cortes, Greenhouse gas(GHGs) emissions have resulted in global warming which further leads to climate change. To reduce GHGs emissions, governors make attempts to create multilateral agreements among countries. Their failure of establishing sustainable agreements drives researchers to find fair and equitable distribution rules. Based on Emission Egalitarianism for each individual, this paper creatively generates the generalized constraint equal awards rule (GEA), provides corresponding algorithm to compute emission allocations from the GEA rule and points out several characteristics of this rule. To determine a fairer rule, this paper introduces Lorenz dominance and proved in n-agent case that the allocation provided by the GEA rule is Lorenz-undominated by all other allocations from any other rules. Furthermore, in a simplified 2-agent case this paper confirmed the allocations derived from the GEA rule Lorenz dominates all other allocations from any other rules.

This research aims at defining a model to assess the Greenhouse Gases emissions of an entire vehicle fleet, from a life cycle perspective, based on the results of specific traffic simulations. The environmental performance of the City of Rome private transport network was evaluated in terms of carbon dioxide equivalent (CO2 eq), was based on the life cycle impacts of the different vehicle categories in circulation and based on the vehicle flow on the road net-work. In terms of life-cycle environmental impact, fully electric vehicles were found to be those with the highest emission values as regards construction, maintenance, and dis-posal, both compared to internal combustion vehicles and hybrid vehicles. Nevertheless, a 100% penetration of electric vehicles in the circulating fleet can potentially generate a reduction of GHG of the order of 39% at transport network level.

[eng] Over the recent decades, several studies revealed the precarious climate situation which is threatening all Life forms on earth, including mankind, even if sometimes we tend to ignore the actual fragility of our situation. Ironically, the human species is at the origin of the rapid change on climate, mostly by practicing unsustainable activities, such as the unregulated consumption of fossil fuels, excessive deforestation, extensive agriculture, and intensive livestock. All these practices have increased the concentration of greenhouse gases in the atmosphere, producing a rapid increase in the average Earth temperature with noticeable consequences in our lifetime. Nevertheless, several efforts have been conducted by the scientific community in order to revert the actual climate situation, even if society acts delayed. One of the actual work routes implies the use of catalysts to capture and convert greenhouse gases into less harmful and more useful chemicals. This route has found in transition metal carbides (TMCs) proficient candidates that could have an important impact in the aforementioned matter. An interesting aspect of TMCs is their capacity to catalyse such transformation reactions at low temperatures and to withstand several reaction cycles without degrading. Precisely, the present Thesis unveils and discusses several reaction mechanisms involved in the greenhouse gases transformation reactions held by TMCs, particularly, focusing on MoCy nanoparticles, a largely unexplored field. This Thesis combines experimental and theoretical approaches to explain the observed experimental evidences, where custom synthetized MoC nanoparticle supported on Au(111) are able to activate methane at room temperature, hydrogenate CO2, and act as superior H2 sponges with respect to clean MoC extended surfaces. Moreover, other important findings are revealed, such as the reconstruction held by some transition metal carbides and nitrides surfaces and the intrinsic nature of clean MoC nanoparticles towards hydrogenation reactions. Overall, the present dissertation intends to encourage further efforts on developing TMC based catalyst able to be used at industrial levels. The experimental section of this thesis has been carried out at the Brookhaven National Laboratory by the group of Prof. J. A. Rodriguez, while the computational part and results analysis has been carried out in the present institution, the Universitat de Barcelona. The results obtained have led to several joint publications., [cat] En els darreres dècades, diversos estudis han revelat la precària situació climàtica que està amenaçant totes les formes de vida a la terra, inclosa la humanitat, encara que de vegades tendim a ignorar la fragilitat de la nostra situació. Irònicament, l’espècie humana és l’origen del ràpid canvi climàtic, principalment per practicar activitats insostenibles, com el consum no regulat de combustibles fòssils, la desforestació excessiva, l’agricultura extensiva i la ramaderia intensiva. Totes aquestes pràctiques han augmentat la concentració de gasos d’efecte hivernacle a l’atmosfera, produint un ràpid augment de la temperatura mitjana de la Terra amb conseqüències notables fins i tot durant la nostra vida. No obstant això, la comunitat científica està realitzant diversos esforços per revertir la alarmant situació climàtica, fins i tot si la societat actua amb retard. Una de les rutes de treball implica l’ús de catalitzadors per capturar i convertir els gasos d’efecte hivernacle en productes químics menys nocius i més útils. Aquesta ruta ha trobat en els carburs de metalls de transició (TMC) candidats competents que podrien tenir un impacte important en la reactivitat esmentada. L’aspecte més interessant dels TMCs és la seva capacitat per catalitzar aquestes reaccions de transformació a baixes temperatures i per suportar diversos cicles de reacció sense degradar-se. Precisament, aquesta Tesi revela i analitza diversos mecanismes de reacció implicats en les reaccions de transformació dels gasos d’efecte hivernacle catalitzades pels TMC, concretament, centrant-se en les nanopartícules de MoCy, que encara romanen inexplorades. Aquesta tesi combina enfocaments experimentals i teòrics per explicar les evidències experimentals observades, on les nanopartícules de MoC sintetitzades suportades sobre Au (111) són capaces d’activar el metà a temperatura ambient, hidrogenar CO2 i actuar com a esponges H2 superiors respecte a les superfícies netes de MoC. A més, altres descobriments importants han estat revelats, com ara la reconstrucció d’algunes superfícies de TMC/TMN i la naturalesa química intrínseca de les nanopartícules de MoC netes pel que fa a les reaccions d’hidrogenació. En general, la present dissertació té la intenció de fomentar nous esforços en el desenvolupament de catalitzadors basats en TMCs que puguin ser utilitzats a nivell industrial. La secció experimental d’aquesta tesi s’ha dut a terme al Brookhaven National Laboratory pel grup del professor J. A. Rodriguez, mentre que la part computacional i l’anàlisi de resultats s’ha dut a terme a la present institució, la Universitat de Barcelona. Els resultats obtinguts han donat lloc a diverses publicacions conjuntes.

The COVID-19 pandemic is having an enormous negative impact on human health, with more than 4.44 million deaths worldwide; on the economy, with an unprecedented deep and abrupt crisis; and on society, with millions of people facing unemployment and dependent, in the best-case scenario, on public welfare or social aid systems. Home confinement, measures to limit non-essential economic activity and travel restrictions in many countries during the spring of 2020 led to rapid air quality improvements in cities. A detailed analysis of Barcelona's daily immissions of seven pollutants (CO, SO2, NO, NO2, NOx, PM10 and O3) shows a clear decrease from mid-March to June, with the peak in April and the nitrogen oxides. For these pollutants the reduction of traffic density is very likely the main cause of their immissions decrease. On another note, the global reduction of CO2 emissions derived from the use of fossil fuels was estimated at approximately 8 % in 2020, which, despite constituting an unprecedented drop, will have little impact on concentrations of CO2 and other greenhouse gases in the atmosphere. The current situation must be seen as an opportunity to push, without delay, for a drastic change in the energy and economy models towards a socio-environmental paradigm based on sustainability, economic efficiency and solidarity between peoples. Resumen. La pandemia de la COVID-19 está teniendo un enorme impacto negativo en la salud humana, con más de 4,44 millones de muertos en todo el mundo; en la economía, con una profunda y abrupta crisis sin precedentes; y en la sociedad, con millones de personas en situación de desempleo y dependientes, en el mejor de los casos, de los sistemas de asistencia social o de bienestar público. El confinamiento domiciliario, las medidas para limitar la actividad económica no esencial y las restricciones de los viajes en muchos países durante la primavera de 2020 llevaron a mejoras rápidas en la calidad del aire de las ciudades. Un análisis detallado de las inmisiones diarias de Barcelona de siete contaminantes (CO, SO2, NO, NO2, NOx, PM10 y O3) muestra una clara disminución desde mediados de marzo hasta junio, con el pico en abril y en los óxidos de nitrógeno. Para estos contaminantes, la reducción de la densidad del tráfico es muy probablemente la principal causa de la disminución de sus inmisiones. Por otro lado, la reducción global de las emisiones de CO2 derivadas del uso de combustibles fósiles se estimó en aproximadamente un 8 % en 2020, lo que, a pesar de constituir una caída sin precedentes, tendrá poco impacto en las concentraciones de CO2 y de otros gases de efecto invernadero en la atmósfera. La situación actual debe ser vista como una oportunidad para impulsar, sin demora, un cambio drástico en los modelos energético y económico hacia un paradigma socioambiental basado en la sostenibilidad, la eficiencia económica y la solidaridad entre los pueblos.

This review focuses on the use of metal–organic frameworks (MOFs) for adsorbing gas species that are known to weaken the thermal self-regulation capacities of Earth’s atmosphere. A large section is dedicated to the adsorption of carbon dioxide, while another section is dedicated to the adsorption of other different gas typologies, whose emissions, for various reasons, represent a “wound” for Earth’s atmosphere. High emphasis is given to MOFs that have moved enough ahead in their development process to be currently considered as potentially usable in “real-world” (i.e., out-of-lab) adsorption processes. As a result, there is strong evidence of a wide gap between laboratory results and the industrial implementation of MOF-based adsorbents. Indeed, when a MOF that performs well in a specific process is commercially available in large quantities, economic observations still make designers tend toward more traditional adsorbents. Moreover, there are cases in which a specific MOF remarkably outperforms the currently employed adsorbents, but it is not industrially produced, thus strongly limiting its possibilities in large-scale use. To overcome such limitations, it is hoped that the chemical industry will be able to provide more and more mass-produced MOFs at increasingly competitive costs in the future.

Treballs finals del Màster "Estudios Internacionales: organizaciones internacionales y cooperación – Colección Memorias MEI", Facultat de Dret, Universitat de Barcelona, Curs: 2019-2020. Tutora: Marta Ortega Gómez., En el presente trabajo se examinará la política medioambiental europea, se informarán las emisiones de gases de efecto invernadero que genera la aviación comercial dentro de la UE, para luego desarrollar aquellas políticas comunitarias que contribuyen a su reducción, además de proponer algunas otras que podrían contribuir a su disminución.

This study proposes, through weighted averages and ordered weighted averaging operators, a new aggregation system for the investigation of average gases emissions. We present the ordered weighted averaging operators gases emissions, the induced ordered weighted averaging operators gases emissions, the weighted ordered weighted averaging operators gases emissions and the induced probabilistic weighted ordered weighted averaging operators gases emissions. These operators represent a new way of analyzing the average gases emissions of different variables like countries or regions. The work presents further generalizations by using generalized and quasi-arithmetic means. The article also presents an illustrative example with respect to the calculations of the average gases emissions in the European region.

Surface mass balance (SMB) variations of the Greenland ice sheet (GrIS) have been identified as an important contributor to contemporary and projected global mean sea level variations, but their impact on the regional sea level change pattern is still poorly known. This study proposes estimates of GrIS SMB over 1900–2100 based on the output of 32 atmosphere–ocean general circulation models and Earth system models involved in phase 5 of the Climate Model Intercomparison Project (CMIP5). It is based on a downscaling technique calibrated against the Modèle Atmosphérique Régional (MAR) regional climate model and it provides an ensemble of 32 Greenland SMB estimates for each Greenland major drainage basin. Because the GrIS SMB does not respond uniformly to greenhouse gas (GHG) emissions, the southern part of the GrIS is more sensitive to climate warming. This study shows that this part should be in imbalance in the twenty-first century sooner than the northern part. This regional variability significantly affects the associated relative sea level pattern over the entire ocean and particularly along the U.S. East Coast and the northern coast of Europe. This highlights the necessity of taking into account GrIS regional SMB changes to evaluate accurately relative sea level changes in future projections.

Renewable Portfolio Standards (RPSs') require that a certain fraction of the electricity generated for a given region be produced from renewable resources. California's RPS mandates that by 2020, 33% of the electricity sold in the state must be generated from renewables. Such mandates have important implications for the electricity sector as well as for the whole society. In this paper, we estimate the costs and benefits of varying 2020 California RPS targets on electricity prices, greenhouse gas (GHG) emissions, criteria pollutant emissions, the electricity generation mix, the labor market, renewable investment decisions, and social welfare. We have extended the RPS Calculator model, developed by Energy and Environmental Economics (E3) Inc., to account for distributions of fuel and generation costs, to incorporate demand functions, and to estimate the effects of RPS targets on GHG emissions, criteria pollutant emissions, and employment. The results of our modeling provide the following policy insights: (1) the average 2020 electricity price increases as the RPS target rises, with values ranging between $0.152 and $0.175/kWh (2008 dollars) for the 20% RPS to 50% RPS, respectively; (2) the 33% and 50% RPS targets decrease the GHG emissions by about 17.6 and 35.8 million metric tons of carbon dioxide equivalent (MMTCO2e) relative to the 20% RPS; (3) the GHG emission reduction costs of the RPS options are high ($71 to $94 per ton) relative to results from policy options other than RPS or prices that are common in the carbon markets; and (4) a lower target (e.g., a 27% RPS) provides higher social welfare than the 33% RPS (mandate) under low and moderate CO2 social costs (lower than $35/ton); while a higher RPS target (e.g., 50%) is more beneficial when using high CO2 social costs or with rapid renewable technology diffusion. However, under all studied scenarios, the mandated 33% RPS for California would not provide the best cost/benefit values among the possible targets and would not maximize the net social benefit objective.

Volcanic and hydrothermal areas largely contribute to the natural emission of greenhouse gases to the atmosphere, although large uncertainties in estimating their global output still remain. Nevertheless, CO2 and CH4 discharged from hydrothermal fluid reservoirs may support active soil microbial communities. Such secondary processes can control and reduce the flux of these gases to the atmosphere. In order to evaluate the effects deriving from the presence of microbial activity, chemical and carbon (in CO2 and CH4) isotopic composition of interstitial soil gases, as well as diffuse CO2 fluxes, of three hydrothermal systems from Italy were investigated, i.e. (i) Solfatara crater (Campi Flegrei), (ii) Monterotondo Marittimo (Larderello geothermal field) and (iii) Baia di Levante in Vulcano Island (Aeolian Archipelago), where soil CO2 fluxes up to 2400, 1920 and 346 g m(-2) day(-1) were measured, respectively. Despite the large supply of hydrothermal fluids, (CO2)-C-13 enrichments were observed in interstitial soil gases with respect to the fumarolic gas discharges, pointing to the occurrence of autotrophic CO2 fixation processes during the migration of deep-sourced fluids towards the soil-air interface. On the other hand, (i) the delta C-13-CH4 values (up to similar to 48% vs. V-PDB higher than those measured at the fumarolic emissions) of the interstitial soil gases and (ii) the comparison of the CO2/CH4 ratios between soil gases and fumarolic emissions suggested that the deep-sourced CH4 was partly consumed by methanotrophic activity, as supported by isotope fractionation modeling. These findings confirmed the key role that methanotrophs play in mitigating the release of geogenic greenhouse gases from volcanic and hydrothermal environments. (c) 2018 Elsevier B.V. All rights reserved.

This paper compares two mathematical models (Model I and Model II) to predict greenhouse gases emission from a University Cape Town (UCT) – membrane bioreactor (MBR) plant. Model I considers N 2 O production only during denitrification. Model II takes into account the ammonia-oxidizing bacteria (AOB) formation pathways for N 2 O. Both models were calibrated adopting real data. Model comparison was performed in terms of (i) sensitivity analysis (ii) best fit and (iii) model prediction uncertainty. On average 6% of factors of Model I and 9% of Model II resulted to be important. In terms of best fit, Model II had a better capability of reproducing the measured data. The average efficiency related to the N 2 O model outputs was equal to 0.33 and 0.38 for Model I and Model II, respectively. On average, 73% (Model I) and 86% (Model II) of measured data lay inside the uncertainty bands.

Difluoromethane (CH2F2,HFC-32) presents strong ro-vibrational bands within the 8–12 μm atmospheric window and hence it represents a greenhouse gas able of contributing to global warming. Numerous spectroscopic studies have been devoted to this molecule, however, much information on line-by-line parameters, like line intensities and broadening parameters, is still lacking. In this work, line-by-line spectroscopic parameters are retrieved for several CH2F2 ro-vibrational transitions belonging to the ν7 band located around 8.5 μm. Self-broadening as well N2– and O2– broadening experiments are carried out at room temperature by using a tunable diode laser (TDL) spectrometer. The line shape analysis of CH2F2 self-broadened spectra leads to the determination of resonant frequencies, integrated absorption coefficients and self-broadening parameters, while CH2F2–N2 and CH2F2–O2 broadening coefficients are obtained from foreign-broadening measurements. In addition, the broadening parameters of CH2F2 in air are derived from the N2– and O2– broadening coefficients. The results of the present work provide fundamental information to measure the concentration profiles of this molecule in the atmosphere through remote sensing spectroscopic techniques.

1 página. Trabajo presentado al: International Conference on Agricultural GHG Emissions and Food Security - Connecting research to policy and practice . Thünen Working Paper, No. 103, Johann Heinrich von Thünen Institut, Braunschweig, (2018). Berlín, Germany, 10-13 septiembre 2018., Most of world's rural population, especially in the Mediterranean areas, depends on livestock for their livelihood.To reduce poverty, fight hunger and ensure global food security, the increase of livestock production was adopted as a sustainable strategy. However, livestock industry, including the raising of cattle, sheep, goat, pigs and poultry and the manufacturing of meat and dairy products, is a significant source of greenhouse gas (GHG) emissions worldwide. The six main GHGs which have a direct impact on climate change are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6). Emissions of CH4, N2O, HFCs, PFCs and SF6 can be converted to CO2 equivalents. HFCs, PFCs and SF6 do not occur naturally in the atmosphere but have been introduced by human activities such as industry, agriculture and energy generation. For about a thousand years before the industrial revolution, the amount of GHG in the atmosphere remained relatively constant. However, since 1970 total concentration of GHG has increased by more than 80 % and since 1990 by 45 % to reach 54 Gt CO2eq. in 2013 against 49 Gt CO2eq. in 2010. In Tunisia, four complete greenhouse gas inventory operations have been carried out in the past, bringing the number of years of complete inventory to 5 years. According to the last inventory, Tunisia's net emissions reached 32.6 million tons of CO2 equivalent (tCO2) in 2012. Dominance was accorded to CO2 emission (69 %) followed by CH4 (21.9 %) and N2O (7.9 %). The same inventory revealed that agriculture, forest and use land (AFUL) are the major contributor to global GHG emission (11 million tons). Livestock contributes by 26 % of the global GHG issued from AFUL, principally in CH4 (2.6 million tons) and N2O (0.23 million tons) form. GHG emissions in Tunisia are projected to increase significantly in the future due to increased demand for agricultural products and changing consumption patterns (e.g., increased meat consumption). Therefore mitigation options of CH4 emission will be recommended as when as it has not result in an increase in the emission of other GHGs such as CO2 and N2O. We have to keep in mind that farmers will adopt the solution only if there is a positive economic impact on animal production and farm profitability.

This research elucidates the pollutants (nutrients and carbon) removal performance and nitrous oxide (N2O) emissions of two pilot plants. Specifically, a University of Cape Town (UCT) Membrane Bioreactor (MBR) plant and an Integrated Fixed Film Activated Sludge (IFAS)-UCT-MBR plant were investigated. The plants were fed with real wastewater augmented with acetate and glycerol in order to control the influent carbon nitrogen ratio (C/N). The short-term effect of the inlet C/N ratio variation (C/N = 5 mgCOD/mgN and C/N = 10 mgCOD/mgN) on the behaviour of both plants was investigated. The results showed that the IFAS-UCT-MBR configuration provided the best performance in terms of pollutants removal at the two investigated C/N ratios. Furthermore, the lowest N2O emission (with respect to the influent nitrogen) was observed in the IFAS-UCT-MBR configuration, thus suggesting a potential beneficial effect of the biofilm in the emission reduction. However, the membrane of the IFAS-UCT-MBR showed a greater fouling tendency compared to the UCT-MBR configuration. This result, likely related to the biofilm detached from carriers, could seriously affect the indirect GreenHouse Gas emissions due to the increase of the energy requirement for permeate extraction with the increase of membrane fouling.

Màster d'Enginyeria Ambiental, Facultat de Química, Universitat de Barcelona, Curs: 2016-2017, Tutors: Joan Dosta, Belén Fernández, Agricultural sector is particularly important in Spanish economy, being one of the main European distributors of pork, with a consumption of 1 kg-pork/week per inhabitant (Faostat 2007). However, it has some negative environmental impacts that clearly affect the global warming. According to data available from 2006 in the National Greenhouse Gas Emissions Inventory, GHG emissions from pig sector in Spain amount to 8.8 million tonnes of equivalent CO2 per year. This has led to several regulations which demand the treatment of surplus. Some mitigation strategies might be implemented at farm-level. Consequently, the main objective of this work was to evaluate two mitigation strategies during storage: acid addition and methanogenic activity inhibitors. To that purpose, a state of the art was carried out to establish the different storage strategies and to select the suitable additive. Manure was characterized and an experimental set-up was performed to simulate anaerobic storage conditions. NH3 and GHG emissions were calculated according to the IPPC Directive tables and a comparison regarding tabulated values of IPPC (European Directive), of attained NH3 and GHGs emissions with these strategies was made. As a secondary objective, an open chamber was designed and set-up to measure NH3 and GHG emissions. Therefore, a decrease of pH to 5.5 H2SO4 contributed to reduce CH4 emissions in a 60% and completely inhibit NH3 but hardly increased SO42- concentration to dangerous levels for planted soils. Thus, organic acids were suitable being less harmful and most effective than strong in reduce GHG emissions, in the case of cow slurry mixture, particularly acetic acid. Related to pig manure, lactic acid showed the same mitigation effect as H2SO4. RY modulate CO2 and NH3 production in the case of the acidification strategy

Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gas (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Riparian soils emitted larger amounts of CO2 (1.2–10 g C m−2 d−1) than N2O (0.001–0.2 mg N m−2 d−1) to the atmosphere attributed to high respiration and low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil water content across the riparian zone. Deep groundwater tables fueled large soil CO2 effluxes near the hillslope, while N2O emissions were higher in the wet zones adjacent to the stream channel. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil water content, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, our results highlight the role of water availability on riparian soil biogeochemistry and GHG emissions and suggest that climate change alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to regional and global biogeochemical cycles.

In this study the performance (in terms of carbon and nutrient removal) and N2O emission of two plant configurations adopting innovative technologies were investigated. With this regards, an University Cape Town (UCT) membrane bioreactor (MBR) plant and an Integrated Fixed Film Activated Sludge (IFAS) -UCT-MBR plant were monitored. Both plants treat real wastewater under two different values of the influent carbon nitrogen ratio (C/N = 5 mgCOD/mgN and C/N = 10 mgCOD/mgN). Results have shown the highest carbon and nutrients removal efficiencies for the IFAS-UCT-MBR configuration during both the two investigated C/N values. Furthermore, the lowest N2O emission occurred for the IFAS-UCT-MBR.

We perform an empirical analysis on the benefits of, and the challenges faced by, sustainability accounting in measuring the effects of climate change for a sample of Spanish rice farms. We use farm yields, revenues and incomes as indicators of economic performance, and greenhouse gas emissions, and direct and indirect energy consumption as indicators of climate change effects. According to our data, farms with higher yields, revenues and income are responsible for a greater environmental impact, measured in total gigajoules of energy consumed and tons of carbon dioxide emitted, than farms with a lower economic performance. Results show that in our sample the achievement of higher yields is attributable to the greater use of chemical inputs and fossil fuels and not to innovative and sustainable farming practices. The results indicate that accounting for climate change effects is not only possible but also necessary to provide more accurate information on the overall costs and benefits of farming. Greater transparency in accounting information should serve to highlight which farming activities are better able to reduce climate change impacts.

The application of Life Cycle Assessment (LCA) to road pavements has been continuously evolving and improving over the last years, however there are several limitations and uncertainties in the introduction of some components in the framework, such as road pavement rolling resistance—in terms of pavement surface properties—and traffic delay during maintenance activities. This paper analyses the influence of methodological assumptions and the model used to estimate the increased emissions for traffic delay and road pavement rolling resistance on the results of an LCA. The Greenhouse Gases (GHG) emissions related to these two phases of a pavement LCA will be calculated for a UK case study, using different models, and a sensitivity test is performed on some specific input variables. The results show that the models used and the input variables significantly affect the LCA results, both for the rolling resistance and the traffic delay

A multistep methodology for the evaluation of the energetic behaviour of a wastewater treatment plant has been carried out, in according to Horizon2020 Enerwater methodology. The study took into account each phase of the process scheme, in order to obtain specific electricity consumption values for all the electro-mechanic devices. Data from both tele-control system and direct measurements in field have been acquired in order to perform a critical analysis for improving energy efficiency.

The optimal supply chain configuration for biomass production on a given territory is identified by a two-tier approach, which considers both the environmental and the economic points of view. The first tier performs a quick evaluation of the supply chain, based on simplified assumptions and on average values of the parameters characterizing the geographical territory. The second tier allows for the inclusion of spatially explicit parameters of the territory and realizes a more detailed optimization of the supply chain using a multi-objective Mixed Integer Linear Programming framework. A demonstrative case study is presented for the bio-fuel supply to a centralized electric power plant. The considered supply chain is based on miscanthus, cultivated in marginal terrains and converted to pyro-oil in a number of delocalized plants for long distance shipment. The results obtained from the two tiers of the model provide quantitative information, to support quick and effective decision making on the optimal configuration of the supply chain in terms of plant size, location, transport logistics and cultivation.

Emissions into the atmosphere of greenhouse gases (GHGs), i.e., carbon dioxide, methane and nitrous oxide from wastewater treatment plants are of increasing concern in the water industry. In order to produce useful and comparable information for monitoring, assessing and reporting GHG emissions from wastewater treatment plants, there is a crescent need for a general accepted methodology. This paper aims at proposing the first protocol for monitoring and accounting GHG emissions from wastewater treatment plants taking into account both direct and internal indirect emissions focusing on sections known to be major responsible of GHG emissions i.e. oxidation tanks and sludge digestion. The main novelties of the proposed protocol are: (i) direct and indirect internal emissions ascribed to aeration devices which are related each other, (ii) the monitoring of biogas composition in case of anaerobic digestion which affects GHG emissions offset due to biogas valorization systems and (iii) monitoring of non-aerated tanks.

Municipal solid waste management significantly contributes to the emission in the atmosphere of greenhouse gases (e.g. CO2, CH4, N2O) and therefore the management process from collection to treatment and disposal has to be optimized in order to reduce these emissions. Many literature models developed for the evaluation of greenhouses gases emissions from the waste management system are based on the analysis of the life cycle. These models are not optimized for evaluation of emissions. The aim of this study is to overcome these limitations by proposing a mathematical model to estimate greenhouse gas emissions resulting from the integrated waste management. The model is aimed to be a verification tool for assessing the optimum system management in terms of greenhouse gas emissions. The model quantify the emissions associated with: heat treatment, landfill disposal, anaerobic digestion plants, recycling, composting. Different combinations of collection scenarios and disposal options have been considered in the Municipal Solid Waste management of the Province of Palermo. The obtained results applying the model show that limits to solid waste management must be clearly defined. In fact changing the limits, the emissions vary. The lower emissions are due to the use of different energy sources.

Biofuels are now an integral part of the energy mix. Today the first generation biofuels represent an immediate operational solution to limit emissions of greenhouse gases in the transport sector. By 2020, second-generation biofuels will complement the range of renewable energies to achieve the objectives of incorporation as proposed by the European Union.

We perform an empirical analysis on the benefits of, and the challenges faced by, sustainability accounting in measuring the effects of climate change for a sample of Spanish rice farms. We use farm yields, revenues and incomes as indicators of economic performance, and greenhouse gas emissions, and direct and indirect energy consumption as indicators of climate change effects. According to our data, farms with higher yields, revenues and income are responsible for a greater environmental impact, measured in total gigajoules of energy consumed and tons of carbon dioxide emitted, than farms with a lower economic performance. Results show that in our sample the achievement of higher yields is attributable to the greater use of chemical inputs and fossil fuels and not to innovative and sustainable farming practices. The results indicate that accounting for climate change effects can provide useful information to reduce climate change impacts.

This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m−2) followed by C. zizanioides (5.3 kg m−2) and C. papyrus (1.8 kg m−2). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m−2, respectively, whereas M. giganteus emitted 3,395 g m−2. Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m−2 and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m−2. The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m−2) followed by C. zizanioides (3.78 kg m−2) and C. papyrus (1.89 kg m−2). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth. © 2014, Springer-Verlag Berlin Heidelberg.

In the frame of the general efforts to reduce atmospheric CO2 emissions different efforts are being carried out to stimulate the use of non-fossil energy sources and raw materials. Among these a significant role is played by the use of waste in Waste to Energy (WTE) plants. In this case a relevant problem is related to the determination of the proportion between the bio and the fossil derived fraction in CO2 atmospheric emissions since only the share of energy derived from the bio-fraction combustion can be labelled as “renewable”. We discuss the potential of radiocarbon in this field by presenting the results of different campaigns carried out by analysing CO2 sampled at the stack of different power plants in Italy with different expected bio-content of the released carbon dioxide. The still open issues related to the calculation procedures and the achievable precision and accuracy levels are discussed.

Aim Savannas and seasonally-dry ecosystems cover a significant part of the world's land surface. If undisturbed, these ecosystems might be expected to show a net uptake of methane (CH 4 ) and a limited emission of nitrous oxide (N 2 O). Land management has the potential to change dramatically the characteristics and gas exchange of ecosystems. The present work investigates the contribution of warm climate seasonally-dry ecosystems to the atmospheric concentration of nitrous oxide and methane, and analyses the impact of land-use change on N 2 O and CH 4 fluxes from the ecosystems in question. Location Flux data reviewed here were collected from the literature; they come from savannas and seasonally-dry ecosystems in warm climatic regions, including South America, India, Australasia and Mediterranean areas. Methods Data on gas fluxes were collected from the literature. Two factors were considered as determinants of the variation in gas fluxes: land management and season. Land management was grouped into: (1) control, (2) 'burned only' and (3) managed ecosystems. The season was categorized as dry or wet. In order to avoid the possibility that the influence of soil properties on gas fluxes might confound any differences caused by land management, sites were grouped in homogeneous clusters on the basis of soil properties, using multivariate analyses. Inter- and intra-cluster analysis of gas fluxes were performed, taking into account the effects of season, land management and main vegetation types. Results Soils were often acid and nutrient-poor, with low water retention. N 2 O emissions were generally very low (median flux 0.32 mg N 2 O m -2 day -1 ), and no significant differences were observed between woodland savannas and managed savannas. The highest fluxes (up to 12.9 mg N 2 O m -2 day -1 ) were those on relatively fertile soils with high air-filled porosity and water retention. The effect of season on N 2 O production was evident only when sites were separated in homogeneous groups on the basis of soil properties. CH 4 fluxes varied over a wide range (-22.9 to 3.15 mg CH 4 m -2 day -1 , where the negative sign denotes removal of gas from the atmosphere), with an annual average daily flux of -0.48 ± 0.96 (SD) mg CH 4 m -2 day -1 in undisturbed (control) sites. Land-use change dramatically reduced this CH 4 sink. Managed sites were weak sinks of CH 4 in the dry season and became sources of CH 4 in the wet season. This was particularly evident for pastures. Burning alone did not reduce soil net CH 4 oxidation, but decreased N 2 O production. Main conclusions Despite the low potential for N 2 O production, both in natural and managed conditions, tropical seasonally-dry ecosystems represent a significant source of N 2 O (4.4 Tg N 2 O year -1 ) on a global scale, as a consequence of the large area they occupy. The same environments represent a potential CH 4 sink of 5.17 Tg CH 4 year -1 . However, assuming that c. 30% of the tropical land is converted to different uses, the sink would be reduced to 3.2 Tg CH 4 year -1 . The limited information on fluxes from Mediterranean ecosystems does not allow a meaningful scaling up.

Emisiones de gases de efecto invernadero y estructuras de consumo en España La aplicación del principio contable de la producción y del consumo permite determinar la responsabilidad de la contaminación atmosférica desde dos perspectivas diferentes. En este artículo, sobre la base del principio contable del consumo, se analiza la relación entre los patrones de consumo de los hogares españoles y las emisiones de los gases de efecto invernadero en 1998. Para ello, se desarrolla un modelo input-output medioambiental ampliado en el que se combinan datos de tablas input-output, encuestas de presupuestos familiares y cuentas satélite sobre las emisiones atmosféricas. Finalmente, se muestra que, aunque los hogares con mayores ingresos son los que más contaminan en términos de unidades equivalentes de CO2, sus patrones de consumo, en cambio, contribuyen algo menos al efecto invernadero.

Net Emissions Avoided by trade (NEA) are the difference between the pollution that would have been produced in a country if it had not exported any products and all the imports required to satisfy its domestic demand had been produced internally, and its actual emissions. The Domestic Technology Assumption (DTA) applied to an Input–Output model is the appropriate method to estimate the NEA. The usual implementation of the DTA involves that the country analyzed should produce a quantity of products equivalent to the monetary value of the imports required to satisfy its final demand (i.e. ‘monetary DTA’). However, due to price differences, the same physical quantity of goods in different countries could have a different monetary value and the estimation of the NEAwould be biased.We show that a ‘physical DTA’, focused on the pollution to produce domestically the importsmeasured in physical units, would be a better approach.We have applied both methodologies to analyze greenhouse gas emissions in Spain 1995–2007. Both methodologies show that Spain is avoiding emissions through trade. However, the NEA increases up to three times when applying the ‘physical DTA’, showing that results from the ‘monetary DTA’ are biased by price differences., JRC.J.5-Sustainable Production and Consumption

[cat] Les normes socials han estat incloses en la teoria de l’acció col.lectiva per a superar les dificultats per explicar perquè la gestió del béns comuns podria ser més efectiva quan s’autoregula per les mateixes comunitats. El paper rellevant de la confiança en els altres s’ha identificat en diversos contextos d’acció social a nivell local, però només recentment s’ha considerat la idea que també podria ser rellevant en el cas de béns comuns de caire global, seguint l’evidència bàsicament descriptiva recollida per Elinor Ostrom. Però fins ara no hi havia proves quantitatives disponibles d’aquesta idea. Utilitzant un conjunt de dades de 29 països europeus durant el període 1990-2007, donem evidència empírica a favor del paper del nivell de confiança en els altres en el context dels béns públics globals. Concloem que el nivell de confiança en els altres té un impacte reductor de les emissions de gasos d’efecte hivernacle; per exemple, l’extrapolació dels resultats implicaria una reducció d’emissions d’Espanya del 12,5% si el nivell mitjà de confiança en els altres dels espanyols fos tan elevat com els dels suecs., [eng] Social norms have been included in the theory of collective action to overcome difficulties in explaining why commons may perform better when self-regulated. The role of trust has been identified in several contexts of local social dilemma, but only recently has been extended to global commons, based on large descriptive evidence collected by Elinor Ostrom. However, no quantitative evidence was available until now. Using a dataset of 29 European countries over the period 1990-2007, we provide empirical evidence in favor of the role of trust in global dilemma. We end up with a negative impact of trust on greenhouse gas emissions, whose extrapolation to Spain would imply a reduction in emissions of 12.5% if Spaniards would trust each other as Swedish people do.

Soil microbial community structure and gas exchange (CH 4, N 2O) were investigated in a rice paddy field, located in the Po plain, Italy. At eight sampling dates-representative for different soil conditions and crop stages-microbial community structure was characterized by phospholipid fatty acid (PLFA) analysis. Principal component analyses revealed differences in community composition as well as in soil fluxes during the monitored year. The vertical distribution of PLFAs was investigated by sampling at 0-15 and 15-30 cm; the uniformity in soil properties through the soil profile resulted in a vertical homogeneity of microbial biomass and community composition. Only temporary variations of soil conditions led to a distinction in microbial populations with depth. The ratio of Gram-positive to Gram-negative bacteria was higher in flooded than in non-flooded soils. The saturated and methyl-branched fatty acids typically present in Gram-positive bacteria appeared to be indicators of flooded and waterlogged conditions, which were favourable for CH 4 emission as well as for N 2O consumption. Gram-negative bacteria were instead most important for characterization of aerobic conditions and for the decomposition of fresh residues. In terms of microbial processes, the 16:1ω9 fatty acid appeared to be correlated with N 2O fluxes. © 2012 Springer Science+Business Media B.V.

97 σ., Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) "Περιβάλλον και Ανάπτυξη", Η παρούσα εργασία έχει ως αντικείμενο την εξέταση και την ανάλυση των μέσων άσκησης ενεργειακής πολιτικής καθώς και της αποτελεσματικότητας τους στην κατεύθυνση της αντιμετώπισης της κλιματικής αλλαγής. Αρχικά μελετάται πολύπλευρα το φαινόμενο της κλιματικής αλλαγής εξετάζοντας τα αίτια που την προκαλούν, τις διαστάσεις της και τις επιπτώσεις της. Στη συνέχεια εξετάζονται τα διάφορα μέσα κλιματικής και ενεργειακής πολιτικής, τα οποία και ταξινομούνται. Έπειτα η εργασία επικεντρώνεται στους μηχανισμούς πιστοποιήσεων, εξετάζοντας τα Λευκά Πιστοποιητικά (WhC), τα Πράσινα Πιστοποιητικά (TGC), τα Συνδυασμένα Πιστοποιητικά Θερμότητας και Ενέργειας (CHP) καθώς και το Σύστημα Εμπορίας Ρύπων και το Ευρωπαϊκό Σύστημα Εμπορίας Ρύπων (EU ETS). Αφού έχουν περιγραφεί όλα τα μέσα κλιματικής πολιτικής, εξετάζονται τα αποτελέσματα από την εφαρμογή των μέσων κλιματικής πολιτικής και ειδικότερα εξετάζονται τα αποτελέσματα από τη εφαρμογή τεσσάρων μέσων: των συστημάτων εμπορίας ρύπων, των περιβαλλοντικών φόρων, των συστημάτων πράσινων πιστοποιητικών και των συστημάτων λευκών πιστοποιητικών Συνεχίζοντας μελετάται η κλιματική πολιτική που εφαρμόζεται στην Ελλάδα, αναλύοντας την ελληνική και την κοινοτική σχετική νομοθεσία καθώς και την προσαρμογή της Ελλάδας στις διεθνής δεσμεύσεις. Τέλος διατυπώνονται κάποια βασικά συμπεράσματα για τις δράσεις αντιμετώπισης της κλιματικής αλλαγής και τη χάραξη μιας ολοκληρωμένης κλιματικής πολιτικής με τη χρήση των κατάλληλων μέσων. Λέξεις Κλειδιά: κλιματική αλλαγή, κλιματική πολιτική, φαινόμενο του θερμοκηπίου, αέρια του θερμοκηπίου., This project examines the analysis of energy policy instruments and the effectiveness in the direction of tackling climate change. Initially is examined the multifaceted phenomenon of climate change by examining the causes of the rise, the dimensions and implications. It then examines the various means climate and energy policy and then they are ordered. Then the paper focuses on the mechanisms of certification, considering the White Certificates (WhC), Green certificates (TGC), the Combined Heat and Energy Certificates (CHP) and the Emissions Trading Scheme and European Emissions Trading Scheme (EU ETS). When all the means pf the climate policy are described, is examined the impact of the implementation of climate policy instruments and particularly the results from the application of four instruments: emissions trading schemes, environmental taxes, green certificates systems and systems of white certificates. Afterwards the study includes the climate policy in Greece analyzing the Greek and EU legislation and the adaptation of Greece's international commitments. Finally, some basic conclusions are made bout actions to face climate change and developing a comprehensive climate policy using the appropriate means., Ιουλία Κ. Χατζοπούλου

Emissions of resuspensed particles from paved roads (RPR) have received an increasing attention in air quality modeling, since chemistry transport models are generally unable to reproduce particulate levels near road traffic. However, among the models operated in the forecasting mode in Europe, there is a lack of systems including the contribution of RPR on an hourly basis. Therefore, this contribution describes the inclusion of the resuspension of particulate matter within HERMES emission model (operationally implemented in the CALIOPE forecasting system) and the improvements obtained in the simulations of the PM10 mass over a domain covering Spain for a whole year of simulation (2004). The results indicate a remarkable improvement of the PM10 predictions, reducing the biases and errors around 15–18% and 2.6 μg m −3 for the average bias in all Spain. The RPR emission have strong local effects on the modeled particle concentration in or near the largest urban zones (up to 7 μg m −3 as the annual average), albeit those positive effects are more limited in background areas, since the deposition mechanism was found to be a significant sink for RPR in the chemistry transport model. This approach is accurate and effective in order to improve the prediction of the PM10 mass and becomes essential to achieve the standards set in the regulations for modeling applications.

Une des attentes forte de la société et des décideurs politiques est de mieux comprendre et de pouvoir anticiper les réponses des agro-écosystèmes aux changements climatiques et atmosphériques anticipés. La prévision sur le long-terme de ces impacts sur la contribution des agro-écosystèmes à l'effet de serre et sur leur potentiel d'atténuation des émissions permis par le stockage de carbone dans la matière organique des sols repose nécessairement sur l'utilisation de modèles. PaSiM est un modèle biogéochimique déterministe à dominante mécaniste se situant à l'échelle de la parcelle de prairie et qui a pour objectif principal de modéliser une prairie spatialement homogène et ses principaux flux de carbone, d'azote et d'eau. Au-delà de cette modélisation "prairie centrée", le modèle FarmSim permet de simuler le comportement de systèmes d'élevage herbagers ou basés sur le maïs à l'échelle de la ferme. Résultant du couplage des modèles PaSiM, CERES (culture) et GESTIM (intrants, calcul des flux à l'étable) il fournit un bilan annuel des émissions de GES à l'échelle de l'exploitation. Ce papier se propose de décrire ces deux modèles et l'intérêt qu'ils présentent pour répondre aux attentes sociales vis-à-vis des impacts du changement climatique sur les prairies et les systèmes d'élevage, One of the expectations of society and stakeholders is to better understand and anticipate agroecosystems responses to atmospheric and climatic changes. Modelling is required to predict long-term climate change impacts on the greenhouse gas (GHG) balance of these ecosystems and their GHG mitigation potental through soil C sequestration. PaSiM is a grassland biogeochimical deterministic and mechanistic model, that assumes homogeneous vegetation and that simulates at plot scale grassland main carbon, nitrogen and water fluxes. At a larger scale, FarmSim couples the models PASIM, CERES (crop) and GESTIM (inputs, fluxes at barn) to make an assessment of GHG balance at the farm level. This paper aims at describing these two models to show in what extent they are useful tools in climate change impact studies on grassland and pasture-based livestock systems

The CALIOPE project, funded by the Spanish Ministry of the Environment, aims at establishing an air quality forecasting system for Spain. With this goal, CALIOPE modeling system was developed and applied with high resolution (4km×4km, 1h) using the HERMES emission model (including emissions of resuspended particles from paved roads) specifically built up for Spain. The present study provides an evaluation and the assessment of the modeling system, coupling WRF-ARW/HERMES/CMAQ/BSC-DREAM8b for a full-year simulation in 2004 over Spain. The evaluation focuses on the capability of the model to reproduce the temporal and spatial distribution of gas phase species (NO(2), O(3), and SO(2)) and particulate matter (PM10) against ground-based measurements from the Spanish air quality monitoring network. The evaluation of the modeling results on an hourly basis shows a strong dependency of the performance of the model on the type of environment (urban, suburban and rural) and the dominant emission sources (traffic, industrial, and background). The O(3) chemistry is best represented in summer, when mean hourly variability and high peaks are generally well reproduced. The mean normalized error and bias meet the recommendations proposed by the United States Environmental Protection Agency (US-EPA) and the European regulations. Modeled O(3) shows higher performance for urban than for rural stations, especially at traffic stations in large cities, since stations influenced by traffic emissions (i.e., high-NO(x) environments) are better characterized with a more pronounced daily variability. NO(x)/O(3) chemistry is better represented under non-limited-NO(2) regimes. SO(2) is mainly produced from isolated point sources (power generation and transformation industries) which generate large plumes of high SO(2) concentration affecting the air quality on a local to national scale where the meteorological pattern is crucial. The contribution of mineral dust from the Sahara desert through the BSC-DREAM8b model helps to satisfactorily reproduce episodic high PM10 concentration peaks at background stations. The model assessment indicates that one of the main air quality-related problems in Spain is the high level of O(3). A quarter of the Iberian Peninsula shows more than 30days exceeding the value 120μgm(-3) for the maximum 8-h O(3) concentration as a consequence of the transport of O(3) precursors downwind to/from the Madrid and Barcelona metropolitan areas, and industrial areas and cities in the Mediterranean coast.

This paper aims to contribute to the discussion regarding accounting for emission trading schemes, introduced on a global scale as a result of the Kyoto Protocol of 1997, which sets binding greenhouse gases emissions targets for 37 industrialized countries and the European Union. The EU Directive 87/2003/EC establishes a scheme for greenhouse gases allowance trading, in order to promote reduction of greenhouse gases in an efficient and cost-effective manner. The European Union has adopted a “cap and trade” scheme (Starbatty, 2010), which establishes a cap on the total amount of greenhouse gases than can be released over a specified period of time. The European Emission Trading Scheme (the EU ETS) started in January 2005 and it is the largest company-level, multi-sector cap and trade emissions trading scheme in the world. Allowances are instruments issued by the administrator (e.g., a government) of the trading scheme and assigned to the participants of the trading scheme. They are transferrable instruments which can be traded, either in an official market or over the counter. Any emission of greenhouse gases must be offset by returning an appropriate number of allowances to the administrator of the scheme. The International Accounting Standards Board (IASB), after withdrawing IFRIC 3, is working, jointly with the US Financial Accounting and Standards Board (FASB), to produce a new standard on emission trading schemes. Thus, at the time of writing, no accounting standard yet exists on how to report emission trading schemes in financial statements. In this paper we discuss the problem of the appropriate accounting for emission trading allowances, considering the relevant literature in this field and the various positions taken by authors and regulatory bodies over the years. Provided that financial reporting should always reflect the economic substance of the phenomena which it aims to portray, we emphasize the difference between emission permits and emission allowances, noting how the latter represent a means of payment for every unit of greenhouse gases emitted. We therefore argue against reporting emission allowances as intangible assets, offering instead an alternative view of these instruments as non-monetary means of payment. We also consider to which extent the current reporting model for financial instrument devised by IAS 32 is applicable to emission allowances. Finally, we comment on the measurement issues that arise at each reporting date for the emission allowances held by the scheme participant.

We measured denitrification at 15 sites during 1 year in a agricultural catchment in Brittany, France. Our objective was to assess the relative importance of heterotrophic denitrification on the fate of excess nitrogen at the catchment scale, and to quantify the relative importance of riparian areas on the N2O emissions. Using the C2H2 inhibition technique, denitrification rate on soil core and denitrifying enzyme activity (DEA) were each determined, for samples taken from two soil layers: 0–20 and 20–40 cm. Denitrification rates, ranging from 0 to 417 mg N m−2 d−1, were significantly higher in riparian areas than for hillslopes (median of 24.87 against 10.38 mg N m−2 d−1). However, since denitrification rates are significant in the hillslope and given that hillslope surface area is much greater (79% of catchment surface), this domain could be responsible for half of the overall denitrified nitrogen (N). Also, the 20–40 cm deep soil layer was found to account for more than 46% of the denitrification. The DEA indicates the potential for denitrifying activity by the soil under non-limiting conditions, measured values ranged from 76.48 to 530.63 ng N g−1 dry soil h−1. The ratio N2O/(N2O + N2) was about 60% with no clear spatial or temporal trends. Soil moisture appeared to be the main limiting factor for denitrification at the field scale. The results suggest that, for this catchment, denitrification is a major route for nitrogen removal, but a significant proportion of this removal occurs as N2O.

A la coberta: Construir Barcelona 2004 Forma part de la col·lecció: Documents; 1

8 Pags.- 2 Tabls.- 5 Figs., In newly irrigated Mediterranean agroecosystems, the combined effect of tillage and N fertilization on soil carbon dioxide (CO2) and methane (CH4) fluxes is at present poorly understood. The goal of this study was to quantify both soil CO2 and CH4 emissions as well as crop performance under different tillage systems and N fertilization rates during three maize (Zea mays L.) growing seasons (2015–2017) in a semiarid area converted to irrigated. Three types of tillage (conventional tillage, CT, reduced tillage, RT, and no-tillage, NT) and three mineral N fertilization rates (0, 200, and 400 kg N ha−1) were compared in a randomized block design with three replications. Weekly soil CO2 and CH4 emissions, soil temperature and gravimetric moisture were measured. Moreover, maize above-ground biomass, grain yield, and above-ground C-inputs were quantified. Carbon dioxide emissions ranged from 173 to 4378 mg CO2-C m-2 d-1. No-tillage showed a greater mean soil CO2 flux than CT when applying the highest rate of N (400 kg N ha-1). Although some emissions of CH4 were observed, all treatments acted as net CH4 sinks during most of the experimental period. A linear multiple relationship between soil CO2 fluxes and soil gravimetric moisture (0–5 cm depth) and temperature (10 cm depth) were found. In the 2015 growing season, greater cumulative CO2 emissions were found under NT and RT compared with CT, while in 2016 N T showed the highest values compared to CT with intermediate values in RT. Differently, in 2017 no differences between tillage systems were found. When applying N fertilizer, NT and RT increased maize grain production and above-ground C-inputs compared to CT, since a severe soil crusting occurred in this last, which caused crop water deficit. The results suggest that tillage intensity and N fertilization rate reduction can increase maize biomass production and yield which leads to greater C-input that returns to the soil., This research work was financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES‐2014‐070039). DPB received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (IJCI-2016-27784).

En aquest article es discuteix per quin motiu algunes molècules senzilles com el CO2 absorbeixen radiació infraroja. A més, es comenta que hi ha altres gasos a l'atmosfera que absorbeixen el mateix tipus de radiació i que, en conseqüència, poden contribuir també a l'efecte hivernacle. Finalment, s'explica el motiu pel qual els dos gasos majoritaris a l'atmosfera de la Terra, el N2 i l'O2, no produeixen aquest efecte. [ENG] The basis of the absorption of infrared radiation by simple molecules such as CO2 is explained. The contribution of other molecules, present in the earth's atmosphere, to the greenhouse effect is also discussed. Finally, the fact that the main atmospheric gases, N2 and O2, are unable to absorb infrared radiation is also explained.

Most global circulation models and climate–chemistry models forced with increasing greenhouse gases predict a strengthening of the Brewer–Dobson circulation (BDC) in the twenty-first century, and some of them claim that such strengthening has already begun at the end of the twentieth century. However, observational evidence for such a trend remains inconclusive. The goal of this paper is to examine the evidence for observed trends in the stratospheric overturning circulation using a suite of currently available observational stratospheric temperature data. Trends are examined as “departures” from the global mean temperature, since such trends reflect the effects of dynamics and spatially inhomogeneous radiative forcing and are to first order independent of the direct radiative effects of increasing well-mixed greenhouse gas concentrations. The primary conclusion of the study is that temperature observations do not reveal statistically significant trends in the Brewer–Dobson circulation over the period from 1979 to the present, as covered by Microwave Sounding Unit and Stratospheric Sounding Unit temperatures. The estimated trends in the BDC are weak in all datasets and not statistically significant at the 95% confidence level. In many cases, different data products yield very different results, particularly when the trends are stratified by season. Implications for the interpretation of recent stratospheric climate change are discussed. The results illustrate the essential need to better constrain the accuracy of future stratospheric temperature datasets.