16 resultados para Impacts of a warming Arctic

em Universidad Politécnica de Madrid


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Transportation infrastructure is known to affect the value of real estate property by virtue of changes in accessibility. The impact of transportation facilities is highly localized as well, and it is possible that spillover effects result from the capitalization of accessibility. The objective of this study was to review the theoretical background related to spatial hedonic models and the opportunities that they provided to evaluate the effect of new transportation infrastructure. An empirical case study is presented: the Madrid Metro Line 12, known as Metrosur, in the region of Madrid, Spain. The effect of proximity to metro stations on housing prices was evaluated. The analysis took into account a host of variables, including structure, location, and neighborhood and made use of three modeling approaches: linear regression estimation with ordinary least squares, spatial error, and spatial lag. The results indicated that better accessibility to Metrosur stations had a positive impact on real estate values and that the effect was marked in cases in which a house was for sale. The results also showed the presence of submarkets, which were well defined by geographic boundaries, and transport fares, which implied that the economic benefits differed across municipalities.

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Purpose The purpose of this paper is to present what kind of elements and evaluation methods should be included into a framework for evaluating the achievements and impacts of transport projects supported in EC Framework Programmes (FP). Further, the paper discusses the possibilities of such an evaluation framework in producing recommendations regarding future transport research and policy objectives as well as mutual learning for the basis of strategic long term planning. Methods The paper describes the two-dimensional evaluation methodology developed in the course of the FP7 METRONOME project. The dimensions are: (1) achievement of project objectives and targets in different levels and (2) research project impacts according to four impact groups. The methodology uses four complementary approaches in evaluation, namely evaluation matrices, coordinator questionnaires, lead user interviews and workshops. Results Based on the methodology testing, with a sample of FP5 and FP6 projects, the main results relating to the rationale, implementation and achievements of FP projects is presented. In general, achievement of objectives in both FPs was good. Strongest impacts were identified within the impact group of management and co-ordination. Also scientific and end-user impacts of the projects were adequate, but wider societal impacts quite modest. The paper concludes with a discussion both on the theoretical and practical implications of the proposed methodology and by presenting some relevant future research needs.

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To determine the risk of nitrate pollution in agricultural systems have identified several indexes and efficiencies that may lead an effective N fertilizer management for obtain the maximum yield with minimum environmental impact and health

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Crops growing in the Iberian Peninsula may be subjected to damagingly high temperatures during the sensitive development periods of flowering and grain filling. Such episodes are considered important hazards and farmers may take insurance to offset their impact. Increases in value and frequency of maximum temperature have been observed in the Iberian Peninsula during the 20th century, and studies on climate change indicate the possibility of further increase by the end of the 21st century. Here, impacts of current and future high temperatures on cereal cropping systems of the Iberian Peninsula are evaluated, focusing on vulnerable development periods of winter and summer crops. Climate change scenarios obtained from an ensemble of ten Regional Climate Models (multimodel ensemble) combined with crop simulation models were used for this purpose and related uncertainty was estimated. Results reveal that higher extremes of maximum temperature represent a threat to summer-grown but not to winter-grown crops in the Iberian Peninsula. The study highlights the different vulnerability of crops in the two growing seasons and the need to account for changes in extreme temperatures in developing adaptations in cereal cropping systems. Finally, this work contributes to clarifying the causes of high-uncertainty impact projections from previous studies.

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Urban areas benefit from significant improvements in accessibility when a new high speed rail (HSR) project is built. These improvements, which are due mainly to a rise in efficiency, produce locational advantagesand increase the attractiveness of these cities, thereby possibly enhancing their competitivenessand economic growth. However, there may be equity issues at stake, as the main accessibility benefits are primarily concentrated in urban areas with a HSR station, whereas other locations obtain only limited benefits. HSR extensions may contribute to an increase in spatial imbalance and lead to more polarized patterns of spatial development. Procedures for assessing the spatial impacts of HSR must therefore follow a twofold approach which addresses issues of both efficiency and equity. This analysis can be made by jointly assessing both the magnitude and distribution of the accessibility improvements deriving from a HSR project. This paper describes an assessment methodology for HSR projects which follows this twofold approach. The procedure uses spatial impact analysis techniques and is based on the computation of accessibility indicators, supported by a Geographical Information System (GIS). Efficiency impacts are assessed in terms of the improvements in accessibility resulting from the HSR project, with a focus on major urban areas; and spatial equity implications are derived from changes in the distribution of accessibility values among these urban agglomerations.

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The implementation of a charging policy for heavy goods vehicles in European Union (EU) member countries has been imposed to reflect costs of construction and maintenance of infrastructure as well as externalities such as congestion, accidents and environmental impact. In this context, EU countries approved the Eurovignette directive (1999/62/EC) and its amending directive (2006 /38/EC) which established a legal framework to regulate the system of tolls. Even if that regulation seek s to increase the efficien cy of freight, it will trigger direct and indirect effects on Spain’s regional economies by increasing transport costs. This paper presents the development of a multiregional Input-Output methodology (MRIO) with elastic trade coefficients to predict in terregional trade, using transport attributes integrated in multinomial logit models. This method is highly useful to carry out an ex-ante evaluation of transport policies because it involves road freight transport cost sensitivity, and determine regional distributive and substitution economic effect s of countries like Spain, characterized by socio-demographic and economic attributes, differentiated region by region. It will thus be possible to determine cost-effective strategies, given different policy scenarios. MRIO mode l would then be used to determine the impact on the employment rate of imposing a charge in the Madrid-Sevilla corridor in Spain. This methodology is important for measuring the impact on the employment rate since it is one of the main macroeconomic indicators of Spain’s regional and national economic situation. A previous research developed (DESTINO) using a MRIO method estimated employment impacts of road pricing policy across Spanish regions considering a fuel tax charge (€/liter) in the entire shortest cost path network for freight transport. Actually, it found that the variation in employment is expected to be substantial for some regions, and negligible for others. For example, in this Spanish case study of regional employment has showed reductions between 16.1% (Rioja) and 1.4% (Madrid region). This variation range seems to be related to either the intensity of freight transport in each region or dependency of regions to transport intensive economic sect ors. In fact, regions with freight transport intensive sectors will lose more jobs while regions with a predominantly service economy undergo a fairly insignificant loss of employment. This paper is focused on evaluating a freight transport vehicle-kilometer charge (€/km) in a non-tolled motorway corridor (A-4) between Madrid-Sevilla (517 Km.). The consequences of the road pricing policy implementation show s that the employment reductions are not as high as the diminution stated in the previous research because this corridor does not affect the whole freight transport system of Spain.

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The Renewable Energy Directive (2009/28/EC) requires that 20% of the EU's energy needs should come from renewable sources by 2020, and includes a target for the transport sector of 10% from biofuels. This report analyses and discusses the global impacts of this biofuel target on agricultural production, markets and land use, as simulated by three agricultural sector models, AGLINK-COSIMO, ESIM and CAPRI. The impacts identified include higher EU production of ethanol and biodiesel, and of the crops used to produce them, as well as more imports of both biofuels. Trade flows of biofuel feedstocks also change to reflect greater EU demand, including a significant increase in vegetable oil imports. However, as the extra demand is small in world market terms, the impact on world market prices is limited. With the EU biofuel target, global use of land for crop cultivation is higher by 5.2 million hectares. About one quarter is area within the EU, some of which would otherwise have left agriculture.

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The economic evaluation of drought impacts is essential in order to define efficient and sustainable management and mitigation strategies. The aim of this study is to evaluate the economic impacts of a drought event on the agricultural sector and measure how they are transmitted from primary production to industrial output and related employment. We fit econometric models to determine the magnitude of the economic loss attributable to water storage. The direct impacts of drought on agricultural productivity are measured through a direct attribution model. Indirect impacts on agricultural employment and the agri-food industry are evaluated through a nested indirect attribution model. The transmission of water scarcity effects from agricultural production to macroeconomic variables is measured through chained elasticities. The models allow for differentiating the impacts deriving from water scarcity from other sources of economic losses. Results show that the importance of drought impacts are less relevant at the macroeconomic level, but are more significant for those activities directly dependent on water abstractions and precipitation. From a management perspective, implications of these findings are important to develop effective mitigation strategies to reduce drought risk exposure.

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Short-range impacts to sensitive ecosystems as a result of ammonia emitted by livestock farms are often assessed using atmospheric dispersion modelling systems such as AERMOD. These assessments evaluate mean annual atmospheric concentrations of ammonia and nitrogen deposition rates at the ecosystem location for comparison with ecosystem damage thresholds. However, predictions of mean annual atmospheric concentrations can be dominated by periods of stable night-time conditions, which can contribute significantly to mean concentrations. AERMOD has been demonstrated to overestimate concentrations in certain stable low-wind conditions and so the model could potentially overestimate the short-range impacts of livestock ammonia emissions. This paper tests several modifications to the parameterisation of AERMOD (v12345) that aim to improve model predictions in low-wind conditions. The modifications are first described and then are applied to three pig farm case studies in the USA, Denmark and Spain to assess whether the modifications improve long-term mean ammonia concentration predictions through improved model performance. For these three case studies, most of the modifications tested improved model performance as a result of reducing the long-term mean concentration predictions, with the largest effect for low- or ground-level sources (e.g. slurry lagoons or naturally ventilated housing).

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An integrated approach composed of a random utility-based multiregional input-output model and a road transport network model was developed for evaluating the application of a fee to heavy-goods vehicles (HGVs) in Spain. For this purpose, a distance-based charge scenario (in euros per vehicle kilometer) for HGVs was evaluated for a selected motorway network in Spain. Although the aim of this charging policy was to increase the efficiency of transport, the approach strongly identified direct and indirect impacts on the regional economy. Estimates of the magnitude and extent of indirect effects on aggregated macroeconomic indicators (employment and gross domestic product) are provided. The macroeconomic effects of the charging policy were found to be positive for some regions and negative for other regions.

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Large-scale transport infrastructure projects such as high-speed rail (HSR) produce significant effects on the spatial distribution of accessibility. These effects, commonly known as territorial cohesion effects, are receiving increasing attention in the research literature. However, there is little empirical research into the sensitivity of these cohesion results to methodological issues such as the definition of the limits of the study area or the zoning system. In a previous paper (Ortega et al., 2012), we investigated the influence of scale issues, comparing the cohesion results obtained at four different planning levels. This paper makes an additional contribution to our research with the investigation of the influence of zoning issues. We analyze the extent to which changes in the size of the units of analysis influence the measurement of spatial inequalities. The methodology is tested by application to the Galician (north-western) HSR corridor, with a length of nearly 670 km, included in the Spanish PEIT (Strategic Transport and Infrastructure Plan) 2005-2020. We calculated the accessibility indicators for the Galician HSR corridor and assessed their corresponding territorial distribution. We used five alternative zoning systems depending on the method of data representation used (vector or raster), and the level of detail (cartographic accuracy or cell size). Our results suggest that the choice between a vector-based and raster-based system has important implications. The vector system produces a higher mean accessibility value and a more polarized accessibility distribution than raster systems. The increased pixel size of raster-based systems tends to give rise to higher mean accessibility values and a more balanced accessibility distribution. Our findings strongly encourage spatial analysts to acknowledge that the results of their analyses may vary widely according to the definition of the units of analysis.

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Projections for world food production and prices play a crucial role to evaluate and tackle future food security challenges. Understanding how these projections will be affected by climate change is the main objective of this study. By means of a bio-economic approach we assess the economic impacts of climate change on agrifood markets, providing both a global analysis and a regionalised evaluation within the EU. To account for uncertainty, we analyse the IPCC emission scenario A1B for the 2030 horizon under several simulation scenarios that differ in (1) the climate projection, from HadleyCM3 (warm) or ECHAM5 (mild) global circulation models; and (2) the influence of CO2 effects. Results of this study indicate that agrifood market projections to 2030 are very sensitive to climate change uncertainties and, in particular to the magnitude of the carbon fertilization effect.

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The agricultural sector could be one of the most vulnerable economic sectors to the impacts of climate change in the coming decades. Climate change impacts are related to changes in the growth period, extreme weather events, and changes in temperature and recipitation patterns, among others. All of these impacts may have significant consequences on agricultural production(Bates, et al.2008. A main issue regarding climate change impacts is related to the uncertainty associated with their occurrence. Climate change impacts can bestimated with simulation models based on several assumptions, among which the future patterns of emissions of greenhouse g asses are quite likely the most relevant, driving the development of future scenarios, i.e. plausible visions of how the future may unfold. Those scenarios are developed as storylines associated with different assumptions about climate and socioeconomic conditions and emissions, with reference figures, such as demographic projections, average global temperatures, etc.(Intergovernmental Panel on Climate Change 2000). Within this context, climate change impact assessment is forced to consider multiple and interconnected sources of uncertainty in order to produce valuable information for policymakers.

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Los efectos del cambio global sobre los bosques son una de las grandes preocupaciones de la sociedad del siglo XXI. Algunas de sus posibles consecuencias como son los efectos en la producción, la sostenibilidad, la pérdida de biodiversidad o cambios en la distribución y ensamblaje de especies forestales pueden tener grandes repercusiones sociales, ecológicas y económicas. La detección y seguimiento de estos efectos constituyen uno de los retos a los que se enfrentan en la actualidad científicos y gestores forestales. En base a la comparación de series históricas del Inventario Forestal Nacional Español (IFN), esta tesis trata de arrojar luz sobre algunos de los impactos que los cambios socioeconómicos y ambientales de las últimas décadas han generado sobre nuestros bosques. En primer lugar, esta tesis presenta una innovadora metodología con base geoestadística que permite la comparación de diferentes ciclos de inventario sin importar los diferentes métodos de muestreo empleados en cada uno de ellos (Capítulo 3). Esta metodología permite analizar cambios en la dinámica y distribución espacial de especies forestales en diferentes gradientes geográficos. Mediante su aplicación, se constatarán y cuantificarán algunas de las primeras evidencias de cambio en la distribución altitudinal y latitudinal de diferentes especies forestales ibéricas, que junto al estudio de su dinámica poblacional y tasas demográficas, ayudarán a testar algunas hipótesis biogeográficas en un escenario de cambio global en zonas de especial vulnerabilidad (Capítulos 3, 4 y 5). Por último, mediante la comparación de ciclos de parcelas permanentes del IFN se ahondará en el conocimiento de la evolución en las últimas décadas de especies invasoras en los ecosistemas forestales del cuadrante noroccidental ibérico, uno de los más afectados por la invasión de esta flora (Capítulo 6). ABSTRACT The effects of global change on forests are one of the major concerns of the XXI century. Some of the potential impacts of global change on forest growth, productivity, biodiversity or changes in species assembly and spatial distribution may have great ecological and economic consequences. The detection and monitoring of these effects are some of the major challenges that scientists and forest managers face nowadays. Based on the comparison of historical series of the Spanish National Forest Inventory (NFI), this thesis tries to shed some light on some of the impacts driven by recent socio-economic and environmental changes on our forest ecosystems. Firstly, this thesis presents an innovative methodology based on geostatistical techniques that allows the comparison of different NFI cycles regardless of the different sampling methods used in each of them (Chapter 3). This methodology, in conjunction with other statistical techniques, allows to analyze changes in the spatial distribution and population dynamics of forest species along different geographic gradients. By its application, this thesis presents some of the first evidences of changes in species distribution along different geographical gradients in the Iberian Peninsula. The analysis of these findings, of species population dynamics and demographic rates will help to test some biogeographical hypothesis on forests under climate change scenarios in areas of particular vulnerability (Chapters 3, 4 and 5). Finally, by comparing NFI cycles with permanent plots, this thesis increases our knowledge about the patterns and processes associated with the recent evolution of invasive species in the forest ecosystems of North-western Iberia, one of the areas most affected by the invasion of allien species at national scale (Chapter 6).

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Las cargas de origen térmico causadas por las acciones medioambientales generan esfuerzos apreciables en estructuras hiperestáticas masivas, como es el caso de las presas bóvedas. Ciertas investigaciones apuntan que la variación de la temperatura ambiental es la segunda causa de reparaciones en las presas del hormigón en servicio. Del mismo modo, es una causa de fisuración en un porcentaje apreciable de casos. Las presas son infraestructuras singulares por sus dimensiones, su vida útil, su impacto sobre el territorio y por el riesgo que implica su presencia. La evaluación de ese riesgo requiere, entre otras herramientas, de modelos matemáticos de predicción del comportamiento. Los modelos han de reproducir la realidad del modo más fidedigno posible. Además, en un escenario de posible cambio climático en el que se prevé un aumento de las temperaturas medias, la sociedad ha de conocer cuál será el comportamiento estructural de las infraestructuras sensibles en los futuros escenarios climáticos. No obstante, existen escasos estudios enfocados a determinar el campo de temperaturas de las presas de hormigón. Así, en esta investigación se han mejorado los modelos de cálculo térmico existentes con la incorporación de nuevos fenómenos físicos de transferencia de calor entre la estructura y el medio ambiente que la rodea. También se han propuesto nuevas metodologías más eficientes para cuantificar otros mecanismos de transferencia de calor. La nueva metodología se ha aplicado a un caso de estudio donde se disponía de un amplio registro de temperaturas de su hormigón. Se ha comprobado la calidad de las predicciones realizadas por los diversos modelos térmicos en el caso piloto. También se han comparado los resultados de los diversos modelos entre sí. Finalmente, se ha determinado las consecuencias de las predicciones de las temperaturas por algunos de los modelos térmicos sobre la respuesta estructural del caso de estudio. Los modelos térmicos se han empleado para caracterizar térmicamente las presas bóveda. Se ha estudiado el efecto de ciertas variables atmosféricas y determinados aspectos geométricos de las presas sobre su respuesta térmica. También se ha propuesto una metodología para evaluar la respuesta térmica y estructural de las infraestructuras frente a los posibles cambios meteorológicos inducidos por el cambio climático. La metodología se ha aplicado a un caso de estudio, una presa bóveda, y se ha obtenido su futura respuesta térmica y estructural frente a diversos escenarios climáticos. Frente a este posible cambio de las variables meteorológicas, se han detallado diversas medidas de adaptación y se ha propuesto una modificación de la normativa española de proyecto de presas en el punto acerca del cálculo de la distribución de temperaturas de diseño. Finalmente, se han extraído una serie de conclusiones y se han sugerido posibles futuras líneas de investigación para ampliar el conocimiento del fenómeno de la distribución de temperaturas en el interior de las presas y las consecuencias sobre su respuesta estructural. También se han propuesto futuras investigaciones para desarrollar nuevos procedimiento para definir las cargas térmicas de diseño, así como posibles medidas de adaptación frente al cambio climático. Thermal loads produced by external temperature variations may cause stresses in massive hyperstatic structures, such as arch dams. External temperature changes are pointed out as the second most major repairs in dams during operation. Moreover, cracking is caused by thermal loads in a quite number of cases. Dams are unique infrastructures given their dimensions, lifetime, spatial impacts and the risks involve by their presence. The risks are assessed by means of mathematical models which compute the behavior of the structure. The behavior has to be reproduced as reliable as possible. Moreover, since mean temperature on Earth is expected to increase, society has to know the structural behavior of sensitive structures to climate change. However, few studies have addressed the assessment of the thermal field in concrete dams. Thermal models are improved in this research. New heat transfer phenomena have been accounted for. Moreover, new and more efficient methodologies for computing other heat transfer phenomena have been proposed. The methodology has been applied to a case study where observations from thermometers embedded in the concrete were available. Recorded data were predicted by several thermal models and the quality of the predictions was assessed. Furthermore, predictions were compared between them. Finally, the consequences on the stress calculations were analyzed. Thermal models have been used to characterize arch dams from a thermal point of view. The effect of some meteorological and geometrical variables on the thermal response of the dam has been analyzed. Moreover, a methodology for assessing the impacts of global warming on the thermal and structural behavior of infrastructures has been proposed. The methodology was applied to a case study, an arch dam, and its thermal and structural response to several future climatic scenarios was computed. In addition, several adaptation strategies has been outlined and a new formulation for computing design thermal loads in concrete dams has been proposed. Finally, some conclusions have been reported and some future research works have been outlined. Future research works will increase the knowledge of the concrete thermal field and its consequences on the structural response of the infrastructures. Moreover, research works will develope a new procedure for computing the design thermal loads and will study some adaptation strategies against the climate change.