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Energy is an essential factor regarding the economic development and for providing a high standard of living to the population of any country. Because energy is produced mainly using classic fuels (coal, oil and gas) for a few decades there are signals regarding their exhaustion. Therefore, mankind should concern more about finding viable alternatives to replace the classical fuels. This way the use of nuclear fuels appeared, then the force of the wind, of the tides and of the photovoltaic cells. However, there are still enough energy resources for further growth of the global energy production. The great consumers are both the major energy producers, only their hierarchy has changed and changes over time. The paper presents all these countries, and also Romania, including its specific developments in recent years.

[Paper in French] The European public policy in favor of the biodiesel consumption is highly debated. Available estimates of the induced land use changes conclude that this policy is inefficient to reduce emissions of GreenHouse Gas. We show that the crop yield evolutions in these estimates are significantly lower than the observed and expected evolutions. This difference is directly related to biased calibration choice of behavioral parameters. We show using the GTAP-BIO framework that a consistent calibration of these parameters leads to a strong reduction (by around 80% in the long run) of the land use changes and induced emissions.

This work focuses on the refinement of sea-states spectral characterisation in the frame of the development of wave energy converters (WECs). Until now, this characterisation has been limited to the consideration of basic global parameters such as the significant wave height and mean wave period. The present work namely underlines - thanks to simplified numerical models - that such a description is not sufficient to account for the performance of WECs, for they still exhibit a large variability in terms of mean production while wave energy and period are fixed. It is therefore needed to refine this description by introducing new wave characteristics, such as the wave groupiness, which is itself related to the sea-state's spectral bandwidth. The classical - spectral - approaches, allowing a statistical analysis of wave groups along with other works in the literature, permit to draw a set of relevant spectral parameters. The sensitivity of simplified offshore WEC models (linear in the frequency domain) to these parameters is then observed. The question of deterministic mean power estimation - namely in the case of non-linear models - is also raised, for it is also related somehow to the bandwidth of the wave field. A sea-state is actually made of a superimposition of various wave systems (as swells and wind-sea). It is then possible to refine even more its description, namely through the multi-system approach. The latter enables indeed to track in time and space the wave systems independently of each other. An algorithm for the automatic spatiotemporal analysis is proposed and illustrated to this end. Lastly, the influence of such description refinements (wave groupiness and multi-system approach) is observed at several locations (Portugal, North Sea, California) by considering various WEC models (linear axi-symmetric heaving devices, 3D SEAREV with non-linear hydrodynamics): in all cases, it is shown that both extended descriptions allow for a better characterisation of the mean WEC performance at both short and long term. Ces travaux portent sur la caractérisation spectrale des états de mer dans le cadre du développement de systèmes récupérateurs de l'énergie des vagues (SREVs). Jusqu'alors, cette caractérisation s'est limitée à des paramètres globaux basiques tels que la hauteur significative et la période moyenne des vagues. Les présents travaux soulignent notamment, à l'aide de modèles simplifiés, que cette description est insuffisante car un SREV montre encore une grande variabilité en termes de production moyenne, ces deux paramètres étant fixés par ailleurs. On s'intéresse donc à raffiner cette description en considérant des caractéristiques de vagues nouvelles, comme le groupement de vagues, lui-même lié à la largeur de bande de l'état de mer. Les approches classiques - spectrales - sur l'étude descriptive des groupes de vagues et la littérature permettent de dégager un certain nombre de paramètres spectraux. On observe ensuite la sensibilité de modèles de SREVs offshore simplifiés (modèles fréquentiels linéaires) à ces paramètres de largeur globale. La question de l'estimation déterministe de performance moyenne (dans le cas de convertisseurs non-linéaires) est également abordée, étant elle-même liée à cette caractéristique. Un état de mer étant constitué de plusieurs systèmes de vagues (houles, mer de vent), il est encore possible de raffiner sa description grâce à une approche multisystème. Celle-ci permet en outre de suivre ces systèmes indépendamment dans le temps et l'espace. Un algorithme d'analyse spatio-temporelle est proposé et illustré à cet égard. Enfin, l'influence de ces raffinements est observée en différents sites (Portugal, Mer du Nord, Californie) sur des cas de SREVs divers (systèmes axi-symétriques linéaires, SEAREV 3D d'hydrodynamique non-linéaire), et montre que dans tous les cas, le raffinement apporté permet de mieux caractériser la production à court et long terme de ces dispositifs.

Climate change will affect agricultural production conditions, which will translate in impacts on yield and cost of production for Quebec farmers. This would likely affect the relative competitive position of Quebec in North America. Using the Delphi technique and partial budgets, climate change scenarios for the 2050 period were elaborated and their impact on relative competitiveness assessed for Quebec and its competitors in North America. Results indicate that Quebec competitive position would improve due to more favorable conditions for corn and apple production and due to worsen conditions for the competitors in maple syrup production.

A model of plant succession has been built for simulating the growth of six species, based on physiological processes such as photosynthesis, growth and maintenance respiration, carbon allocation, nitrogen absorption, fixation and remobilisation, organ mortality, seed dispersal and germination. The simulated global plant productivity decreases in response to an increase in soil nitrogen availability. The reason is a replacement of the rapidly-growing legume species by slow-growing shrub species that are higher than the legume and thus shade it. This paradoxical result could have a wide application field.

The study of two pollen sequences from El-Kala marshes allowed the reconstruction of the regional vegetation history supported by eight radiocarbon dates. Pollen assemblages from Bourdim site were dominated by local input of Alnus and Salix, while regional vegetation was characterized by scattered Quercus suber forests with a well-developed Erica arborea matorral. While the vegetation dynamics recorded at Bourdim is recent (Late Holocene), the majority of the pollen diagram from Garaat El-Ouez is contemporaneous to the Late Pleniglacial and is characterized by open woodlands with Pinus, Poaceae and several heliophilous herbs. The significant values of Cedrus pollen identified in this period indicate that the region of El-Kala most probably played the role of a refugium for this tree.

Metadata only record This document presents an analysis of Fulani pastoral farming systems that focuses on how pastoralists use silvopastoral land. It aims to provide the missing knowledge needed to implement the resource management ('gestion des terroirs') approach at village level. In this region the influence of pastoral land use on the environment appears to be less pronounced than that of crop cultivation, even though levels of animal production are reasonable. The carrying capacity of the region has not yet been attained. Current constraints to pastoral land use in the region arise from the encroachment of cropland at the expense of pastoral land, and the increase in animal numbers. To develop sustainable natural resource management at village level that includes Fulani pastoral land use, the key factors appear to be the integration of livestock husbandry and cropland cultivation at household level, agreements between pastoralists and cropland farmers on land tenure and resource management, and support targeting of Fulani households (which have so far been neglected). Specific recommendations are given. (CAB Abstract)

L’objectif principal de ce travail est d’analyser l’impact du changement climatique sur la productivité des cultures céréalières dans la région de Béja, située au nord-ouest de la Tunisie. Pour ce faire, des modèles de régression multiple ont été estimés pour trois cultures céréalières (blé dur, blé tendre et orge). Les variables explicatives du rendement utilisées dans l’analyse sont celles d’ordre climatique (précipitations et températures) et le progrès technique. La période d’analyse est de 1980 à 2009. Les estimations des modèles de régression semi-logarithmiques ont montré que les rendements des différentes cultures céréalières dépendaient des variables climatiques et du progrès technique. L’analyse de la projection des effets du changement climatique sur les rendements céréaliers dans la zone d’étude, en utilisant les scénarios du modèle HadCM3, a montré que l’impact est important à l’horizon de 2030. Cet impact sera plus accentué pour le blé tendre. Ainsi, l’encouragement de la recherche en matière d’identification de nouvelles techniques agricoles, la diffusion de variétés tolérantes à la diminution des précipitations, dans les périodes critiques de croissance, et de variétés précoces, font partie des stratégies d’adaptation pour la réduction des effets du changement climatique sur le rendement céréalier à long terme...... This article analyzes the potential impact of climate change on cereal productivity in the Béja region of northwestern Tunisia. Multiple regression models were estimated for the cereal crops durum wheat, bread wheat and barley, using annual data from 1980 to 2009. The yield of each crop was used as the dependent variable, while the explanatory variables were mainly related to the climate (precipitation and temperature) and technological progress. The results show that yield variability is affected by climate and technological progress variables. The projected climate change scenarios predicted by the HadCM3 model will have a significant effect on crop yields by 2030, particularly for bread wheat. Some adaptation strategies that could alleviate climate change effects on cereal crops yields in the long run are the identification of new agricultural practices in this area, the widespread diffusion of varieties that can tolerate rainfall shortage during the critical periods, and the adoption of early maturing varieties.

[ES] Este trabajo presenta una parte de los resultados obtenidos durante el proyecto de cooperación internacional PIRAGUA (EFA210/16), co-financiado por el Programa Interreg EFA (España-Francia-Andorra). Entre 2018 y 2021, el proyecto PIRAGUA abordó, mediante la cooperación transfronteriza, la evaluación del ciclo hidrológico y los recursos hídricos en los Pirineos, en el presente y en futuro, en el contexto del cambio climático. Para ello, los socios del proyecto unificaron y homogeneizaron la información hidrológica existente, propusieron indicadores hidrológicos, analizaron las tendencias observadas en dichos indicadores, desarrollaron modelos de simulación para conocer en detalle los distintos componentes del balance hídrico, y realizaron simulaciones numéricas a partir de proyecciones climáticas bajo distintos escenarios de emisiones de gases de efecto invernadero para evaluar las consecuencias del cambio climático sobre el ciclo hidrológico y los recursos hídricos de los Pirineos. El objetivo de este volumen es realizar una caracterización de los recursos hídricos superficiales y subterráneos de los Pirineos, así como de la gestión y uso de dichos recursos (Capítulo 1); analizar los registros de caudal, niveles de acuíferos e inundaciones para determinar patrones espaciales y determinar las tendencias temporales observadas en las últimas décadas (Capítulo 2); aplicar herramientas de simulación para ampliar el conocimiento sobre los distintos componentes del balance hídrico de los Pirineos (Capítulo 3); y realizar una serie de experimentos de simulación numérica para determinar los posibles cambios del balance hídrico y los recursos hídricos de los Pirineos a lo largo del siglo XXI, en un contexto de cambio climático (Capítulo 4). [FR] Ce travail présente une partie des résultats d'un projet de coopération internationale du Programme Interreg EFA (Espagne-France-Andorre). Entre 2018 et 2021, le projet PIRAGUA (EFA210/16) a abordé, par le biais de la coopération transfrontalière, l'évaluation du cycle hydrologique et des ressources hydriques dans les Pyrénées, pour le présent et l'avenir, dans le contexte du changement climatique. Pour cela, les partenaires du projet ont unifié et homogénéisé les informations hydrologiques existantes, proposé des indicateurs hydrologiques, analysé les tendances observées pour ces indicateurs, développé des modèles de simulation pour connaître les détails du bilan hydrique et réalisé des expériences de simulation numérique, afin d'évaluer les conséquences de scénarios de changement climatique sur le cycle hydrologique et les ressources hydriques des Pyrénées. L'objectif de ce volume est de réaliser une caractérisation des ressources hydriques de surface et souterraines des Pyrénées, de la gestion et de l'emploi des ressources (Chapitre 1) ; analyser les registres de débit, le niveau des aquifères et les inondations afin de déterminer des schémas spatiaux ainsi que les tendances temporelles observées ces dernières décennies (Chapitre 2) ; appliquer des outils de simulation pour réaliser un diagnostic des différents éléments du bilan hydrique des Pyrénées (Chapitre 3); réaliser une série d'expériences de simulation pour déterminer les éventuels changements du bilan hydrique et des ressources hydriques des Pyrénées tout au long du XXIᵉ siècle, dans un contexte de changement climatique (Chapitre 4). [EN] This volume presents part of the results obtained during the international cooperation project PIRAGUA (EFA210/16), co-financed by the Interreg EFA Program (Spain-France-Andorra). Between 2018 and 2021, the PIRAGUA project addressed, through cross-border cooperation, the evaluation of the hydrological cycle and water resources in the Pyrenees, in the present and in the future, in the context of climate change. To do this, the project partners unified and homogenized the existing hydrological information, proposed hydrological indicators, analyzed the trends observed in said indicators, developed simulation models to know in detail the different components of the water balance, and carried out numerical simulations based on projections under different scenarios of greenhouse gas emissions to assess the consequences of climate change on the hydrological cycle and the water resources of the Pyrenees. The objective of this volume is to carry out a characterization of the surface and underground water resources of the Pyrenees, as well as the management and use of said resources (Chapter 1); analyze flow records, aquifer levels, and floods to determine spatial patterns and determine temporal trends observed in recent decades (Chapter 2); apply simulation tools to expand knowledge about the different components of the water balance of the Pyrenees (Chapter 3); and carry out a series of numerical simulation experiments to determine possible changes in the water balance and water resources of the Pyrenees throughout the 21st century, in a context of climate change (Chapter 4). This report was developed within the project EFA210/16 PIRAGUA (“Evaluación y prospectiva de los recursos hídricos de los Pirineos en un contexto de cambio climático, y medidas de adaptación con impacto en el territorio / Evaluation et prospective des ressources en eau des Pyrénées dans un contexte de changement climatique, et mesures d’adaptation avec un impact sur le territoire”), co-funded by the European Regional Development Fund (ERDF) through the Interreg V-A Spain France Andorra program (POCTEFA 2014-2020) (65%) and the project’s partners: CSIC, UPV/EHU, UB, OE, IGME, CNRS, BRGM, INRAE and OBSA (35%). [FR] Un fichier PDF avec la version pré-imprimée du document; [EN] One PDF files with the pre-print version of the document; [ES] Un archivo PDF con la versión de pre-impresión del documento. Peer reviewed