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Impact du changement climatique sur l’évolution des ressources en eau passées et futures (Explore2) – Méthodologie et focus sur la Meuse
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Externalisation de la décarbonisation ? Comment le commerce a façonné l'empreinte carbone de la France (2000-2014)
No full textInternational audienceThis study investigates the evolution of France’s carbon footprint from 2000 to 2014, with a particular focus on the role of international trade. During this period, France’s territorial emissions decreased by 18%, yet its consumption-based footprint declined by only 5%. This divergence reflects an increase in emissions embedded in imports, which grew from 45% to 54% of the total. To analyze these dynamics, we develop a novel structural decomposition framework that disentangles the contributions of scale, composition, and technique effects from a consumption perspective. Our approach extends existing methods by explicitly distinguishing between domestic and foreign influences, and by separately analyzing trade openness and the geographic reallocation of imports. The results highlight the dominance of the technique effect in reducing emissions (-28%), driven primarily by efficiency improvements abroad rather than domestic progress. By contrast, the geographic composition effect substantially increased emissions (+18%), particularly before 2008, when France’s import sourcing shifted toward more carbon-intensive trading partners such as China. France’s situation is emblematic of economies that have already achieved relatively low domestic emissions—through nuclear energy and de-industrialization—and have thus become increasingly dependent on foreign improvements for further reductions. This reliance raises concerns about the externalization of mitigation outcomes and underscores the limits of climate strategies focused solely on territorial emissions. Our findings call for stronger coordination between trade and climate policies to ensure that future decarbonization pathways remain consistent with global mitigation objectives.Cette étude analyse l'évolution de l'empreinte carbone de la France entre 2000 et 2014, en mettant l'accent sur le rôle du commerce international. Alors que les émissions territoriales de la France ont diminué de 18%, son empreinte basée sur la consommation n'a baissé que de 5%, reflétant la croissance des émissions incorporées dans les échanges commerciaux (de 45% à 54% du total). À l'aide d'une nouvelle analyse de décomposition structurelle, nous distinguons les contributions des effets d'échelle, de composition et de technique du point de vue de la consommation. Notre approche améliore les méthodes traditionnelles en différenciant explicitement les influences domestiques et étrangères et en analysant séparément l'ouverture commerciale et la réallocation géographique des flux commerciaux. Les résultats soulignent la prédominance de l'effet technique dans la réduction des émissions (-28%), principalement due aux améliorations d'efficacité à l'étranger. Cependant, la composition géographique a considérablement augmenté les émissions (+18%), notamment par des réorientations vers des partenaires commerciaux à forte intensité carbone avant 2008. Ce schéma—où les réductions d'émissions dépendent de plus en plus des améliorations étrangères—préfigure probablement ce qui attend d'autres économies développées à mesure que la décarbonation domestique progresse, suggérant un besoin accru de coordination des politiques commerciales et climatiques
Economic performance of 3 farm systems differing in sward species diversity and nitrogen fertilization level across a range of future economic scenarios
No full textInternational audienceThe objective of this study was to compare the economic performances of 3 pasture-based systems: a perennial ryegrass (Lolium perenne L.; PRG) receiving 250 kg N/ha (PRG-250N); a PRG-white clover (Trifolium repens L.; WC) receiving 125 kg N/ha (PRGWC-125N); and a multispecies (MSS) sward composed of grasses, legumes, and herbs receiving 125 kg N/ha (MSS-125N). Sward and animal performances were measured over 3 years in a system-scale study involving 3 farmlets at Teagasc Moorepark, Ireland. Subsequently, based on the physical data collected, an economic performance of each sward system was evaluated using current output prices and input costs in the Moorepark Dairy Systems Model. The economic results show similar net farm profitability for both PRG-250N and PRGWC-125N. The PRGWC-125N system had lower costs linked to fertilizer; however, more grass silage was purchased due to reduced grass production. The MSS-125N system outperformed both PRG-250N and PRGWC-125N in net farm profitability (+€167/ha and +€148/ha, respectively) due to increased milk output coupled with reduced N fertilizer use. Sensitivity analyses indicated that MSS-125N was the most profitable system under varying milk and fertilizer prices. Given the variability of clover and herb establishment between paddocks for PRGWC-125N and MSS-125N, an increase in the reseeding frequency and oversowing frequency was simulated and resulted in reductions in farm profitability for both systems (€-14.25/ha per year and €-28.25/ha per year, respectively). This study underscores the potential of increasing sward species diversity using clovers and herbs to sustain economic performances of pasture-based systems while reducing fertilizer N reliance and enhancing animal performance. Further long-term research is required to investigate persistence and economic viability of both PRGWC and MSS under varying climatic and management conditions to validate the longer-term results of the first 3 years of the study
The CO2 + 2,3,4-trimethylpentane and CO2 + 2,2,4,6,6-pentamethylheptane binary systems: high–pressure phase equilibria measurements
No full textInternational audienceTwo binary systems containing CO2 and a branched alkane were newly studied in this work: CO2 + 2,3,4-trimethylpentane and CO2 + 2,2,4,6,6-pentamethylheptane. Their fluid phase behavior was investigated using a high pressure variable-volume cell and a synthetic method. Saturation pressures were visually measured from (293.15 et 363.15) K and for 10 different CO2 mole fractions for both mixtures. Whatever the considered system, no liquid-liquid immiscibility was observed in this temperature range, suggesting a continuous vapor-liquid critical curve between the pure components critical points. A total of 160 points were acquired: 149 bubble points and 11 dew points. These new experimental data were satisfactory modeled by using the Peng-Robinson equation of state with a temperature-dependent interaction parameter, kij (T), fitted against the data
Flash Profile method, is it suitable for complex multi-layered products? Application to strawberry-filled biscuits: a “SWEET project”
No full textInternational audienceComposite foods are consumed daily, but understanding their sensory properties is a major challenge. This study aims to evaluate the efficiency of Flash Profile (FP) method to characterize strawberry-filled biscuits properties, in a context of sugar reduction. Investigations were carried out on fillings (with/without added sugar, with/ without strawberry aroma), then biscuits (with sugar or maltitol or sorbitol, with/without vanilla aroma) and finally on the complex fruit-filled biscuits, corresponding to a progressive matrix complexification strategy.FP allowed a discrimination of the products for the 3 matrices according to their formulation and flavouring. Fruit fillings and biscuits were described with both flavour and texture attributes, whereas fruit-filled biscuits were mainly described with texture attributes. This texture predominance could result from complex changes of texture perceived during chewing. Panellists may also have focused on the first perceived characteristics or on the product's most distinguishing features to ease the task.FP was efficient to discriminate samples in each set of samples according to formulation. The characteristics allowing differentiation between samples varied depending on the matrix. Flavour attributes were mainly used for fluid matrices while texture was dominant for solid matrices. In our study, all panellists evaluated the 3 sets of products in the same order which could have influence their evaluation of complex products during the last session. Further investigations about the evaluation of complex solid products with FP may determine if texture is always dominant, even with a lower number of products.</p
Exploring the productivity per unit of livestock, land and labour of organic multi-species livestock farms in six European countries
No full textInternational audienceFarm diversification is increasingly suggested as a way to improve agriculture's productivity and sustainability. However, the role of livestock remains under-explored, particularly whether diversification of organic farms with multiple livestock species increases productivity. We assessed the livestock, land and labour productivity of 96 organic multi-species livestock farms in six European countries. We aggregated farm's production of commercialized crop and livestock products in a unit of agricultural production (kg of protein) and an economic unit (income in €). We then calculated agricultural productivity of each farm per unit of livestock (LSU), land (ha) and labour (AWU). We also calculated the livestock productivity (kg of protein per LSU) of each livestock enterprise (dairy cattle, beef cattle, meat sheep, dairy sheep, goats, poultry and pigs) on each farm. We found that most organic multi-species livestock farms are as productive as their specialised counterparts per unit of livestock, land and labour, with medians of 103.8 kg of protein/LSU, 91.2 kg of protein/ha and 2214.7 kg of protein/AWU, respectively. Farms that included a monogastric species had higher agricultural productivity than those that included ruminant species alone (i.e., cattle and sheep). The high variability among farms and livestock species requires nuancing the view of diversification as a silver-bullet strategy and exploring the factors that promote or hinder the success of livestock diversification to increase productivity. This study provides the first comparison of agricultural and economic productivity of organic multi-species commercial farms across six European countries and including seven livestock combinations
Evaluating soil communities sensibility to forest structure through the use of eDNA metabarcoding and the Index of Biodiversity Potential
No full textInternational audienceSince the United Nations Conference on Environment and Development and Forests at Rio in 1992, sustainable forest management has included the obligation to preserve biodiversity. However, monitoring the impact on forest management on biodiversity remains difficult due to the complexity, cost and expertise required for taxonomic surveys. The Index of Biodiversity Potential (IBP) has been developed in 2008 to provide forest managers with a rapid habitat assessment tool and has proved to be a valuable tool to reflect above-ground diversity for many taxa. However, most forest diversity lives underground in soil, and the question remains as to whether such an indicator could also reflect changes in below-ground diversity. We sampled 86 forest plots in two distinct regions of South-west France to characterize soil communities through the metabarcoding of eDNA targeting the 18S barcode for eukaryotic taxa. We also assessed the IBP on each plot, as well as several physicochemical parameters. We examined the relationship between IBP —based on ten factors— and its components on the local diversity and composition of communities and compared the responses of distinct phyla within each region. Our results revealed contrasting correlations between the total IBP score, its factors and several phyla.Furthermore, results were different across the two regions studied, suggesting that correlations were partly context dependent. Our results show that structural features typical of mature stands—such as dead wood, habitat trees, and large-diameter trees—also influence the diversity of soil taxa, similarly to aboveground taxa.This supports the complementarity between eDNA metabarcoding and IBP evaluation to target key forest structural traits and their importance for soil biodiversity
Spillover from flower plantings benefits apple pollination on a small scale
No full textInternational audienceAnimal-mediated pollination is critical to support crop yields but is threatened by the decline of pollinator populations. The establishment of flower plantings in agricultural landscapes is a conservation strategy that aims to provide diverse floral resources for pollinators. Despite several studies on the effect of flower plantings on pollination, their effects remain unclear. In particular, the influence of the distance has been studied through theoretical approaches but field studies are scarce. We conducted field experiments over two years, 2023 and 2024, in the Provence-Alpes-Côte d'Azur region of France, to investigate how co-flowering plantings affect insect flower visitation and crop pollination in apple orchards. We found that the abundance of apple flower visitors, especially wild bees, decreased with the distance from flower plantings, thus suggesting a spillover of flower visitors from flower plantings into adjacent apple trees. Interestingly, we found a non-linear effect of the distance from flower planting on the initial fruit set, which suggests that flower plantings can improve apple pollination at close distances from the plantings (about 33 m). No effect of the distance from flower plantings was observed on the diversity of flower visitors, final apple fruit set or fruit quality. Overall, our results suggest that flower plantings are a promising strategy to support pollinators. Furthermore, as they can increase pollinator abundance in the adjacent apple flowers, flower plantings have the potential to enhance pollination and yield of the adjacent crops. Given the short distance of the observed facilitation effect, we recommend that flower plantings should be spread across farmland in order to promote crop pollination at farm level
Préférences des consommateurs pour l'huile de caméline : impact des perceptions sensorielles et de la divulgation d'informations sur l'acceptation d'une huile peu connue issue d'une culture mineure
No full textInternational audienceThis study aims to assess how French consumers evaluate the traditional but unfamiliar camelina oil, focusing on liking scores and willingness to pay (WTP) through sensory perception and information disclosure. In a controlled lab experiment (n = 132, Dijon, France), participants first blind-tasted camelina oil, with half of them evaluating extra virgin olive oil under similar conditions for comparison. After this blind step, stepwise information disclosure on product identity, health and environmental benefits, and possible gene-editing (GE) improvements was proposed.First, the blind tasting showed that 35 % of consumers disliked the camelina oil, while 45 % liked it. The correlations between liking scores and WTP are positive but relatively weak, particularly for the camelina oil, which had been previously seen in stores by only 12 % of participants.Second, information disclosure had a significant impact on WTP. (1) The identification of organic camelina oil led to a significant increase in WTP, while a similar disclosure for extra virgin olive oil had no effect. Additional messages about (2) the benefits of the camelina oil for human health and the environment led to significant increases in WTP. Conversely, (3) GE information reduced WTP for 46.2 % of participants, despite being framed with positive outcomes. These findings highlight the importance of targeted messages in promoting novel, sustainable food products and underline the need to address consumer concerns regarding biotechnology.Cette étude vise à évaluer la manière dont les consommateurs français apprécient l'huile de caméline, un produit traditionnel mais peu connu, en se concentrant sur les notes d'appréciation et la disposition à payer (WTP) à travers la perception sensorielle et la divulgation d'informations. Dans le cadre d'une expérience contrôlée en laboratoire (n = 132, Dijon, France), les participants ont d'abord goûté à l'aveugle de l'huile de caméline, la moitié d'entre eux évaluant également de l'huile d'olive extra vierge dans des conditions similaires à des fins de comparaison. Après cette étape à l'aveugle, des informations ont été progressivement divulguées sur l'identité du produit, ses bienfaits pour la santé et l'environnement, ainsi que les améliorations possibles grâce à l'édition génétique (GE). Tout d'abord, la dégustation à l'aveugle a montré que 35 % des consommateurs n'aimaient pas l'huile de caméline, tandis que 45 % l'appréciaient. Les corrélations entre les notes d'appréciation et la WTP sont positives mais relativement faibles, en particulier pour l'huile de caméline, que seuls 12 % des participants avaient déjà vue en magasin. Ensuite, la divulgation d'informations a eu un impact significatif sur la WTP. (1) L'identification de l'huile de caméline biologique a entraîné une augmentation significative de la WTP, tandis qu'une divulgation similaire pour l'huile d'olive extra vierge n'a eu aucun effet. Des messages supplémentaires sur (2) les bienfaits de l'huile de caméline pour la santé humaine et l'environnement ont entraîné une augmentation significative de la WTP. À l'inverse, (3) les informations sur la GE ont réduit la WTP pour 46,2 % des participants, bien qu'elles aient été présentées sous un angle positif. Ces résultats soulignent l'importance des messages ciblés dans la promotion de produits alimentaires novateurs et durables, et mettent en évidence la nécessité de répondre aux préoccupations des consommateurs concernant les biotechnologies
Quel avenir pour les politiques publiques en faveur de la démocratie alimentaire ?
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