HAL Collection UNC (Univ. de la Nouvelle Calédonie)
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Assessment of Future Precipitation Changes in Mediterranean Climate Regions From CMIP6 Ensemble
No full textInternational audienceABSTRACT Previous studies have indicated a large model disagreement in the future projections of precipitation changes over Mediterranean climate (MedClim) regions worldwide. The majority of these highly populated regions have experienced major droughts in the recent decades, raising concerns about future precipitation changes and their impacts. Here, we examine precipitation projections in five MedClim regions from the CMIP6 ensemble, focusing on model consensus regarding the direction and magnitude of future precipitation changes. Our analysis spans the period 2050–2079 relative to 1970–1999, considering two climate change scenarios (SSP2‐4.5 and SSP5‐8.5) across the Mediterranean Basin (MED), California (CAL), the central coast of Chile (SAA), the Cape Province area of South Africa (SAF), and southwest Australia (AUS). The CMIP6 ensemble mean suggests that annual mean cumulative precipitation will decrease over all the regions except northern California, primarily due to a reduction in winter precipitation, and except over the Mediterranean Basin, where the most significant decrease occurs in autumn. Model agreement on the sign of future precipitation changes is high where the ensemble mean indicates a decrease, but lower where an increase or no changes are projected. Additionally, consecutive dry days (CDD) are expected to increase across all regions, whilst consecutive wet days (CWD) are expected to decrease. Maximum 1‐day precipitation is projected to increase uniformly across all regions. We conclude that despite substantial improvements to the new CMIP6 generation of models, the model spread in future precipitation projections in MedClim regions continues to be high. Impact studies need to account for these uncertainties and consider the whole intermodel range of projected precipitation changes
Nouvelle-Calédonie : entre rivalités locales et enjeux indo-pacifiques
No full textInternational audienceThis conference provided an opportunity to offer a fresh geopolitical perspective on the situation in New Caledonia, linking local rivalries (stemming from the political, social, and identity divisions resulting from the self-determination referendums and the violence of May 2024) with regional strategic issues related to New Caledonia's place in the Indo-Pacific. Pierre-Christophe Pantz showed that the archipelago is currently at the crossroads of internal dynamics undergoing restructuring and international covetousness fueled by its geostrategic position, its resources (particularly nickel), and its role in France's Indo-Pacific strategy. Through his analysis of the recent Bougival Agreement (July 2025), he highlighted the ambivalence of an institutional compromise that seeks to reconcile local stability with regional diplomatic openness.Cette conférence a permis de proposer une lecture géopolitique renouvelée de la situation néocalédonienne, en articulant les rivalités locales (héritées des fractures politiques, sociales et identitaires issues des référendums d’autodétermination et des violences de mai 2024) et les enjeux stratégiques régionaux liés à la place de la Nouvelle-Calédonie dans l’indo-pacifique. Pierre-Christophe Pantz a montré que l’archipel se trouve aujourd’hui à la croisée de dynamiques internes en recomposition et de convoitises internationales nourries par sa position géostratégique, ses ressources (notamment le nickel) et son rôle dans la stratégie indopacifique française. À travers l’analyse du récent accord de Bougival (juillet 2025), il a souligné les ambivalences d’un compromis institutionnel cherchant à concilier stabilité locale et ouverture diplomatique régionale
Zones d’hivernage protégées: stabilité des populations et conservation des limicoles migrateurs à l’île Europa, Océan Indien occidental
No full textInternational audienceThe tropical western Indian Ocean islands are at the southern limit of the East Africa–West Asia Flyway, but their importance for wintering and conservation of Palearctic waders remains poorly understood. Europa Island, a remote coralline island in the southern Mozambique Channel, is a Ramsar site administered since 2005 and managed since 2007 by the Terres australes et antarctiques françaises (TAAF). Although the island is best known for its important seabird assemblages, its importance as a major breeding site for green turtles, and for its native vegetation and undisturbed coral reefs, it also supports a variety of migratory waders from the Palearctic. However, their abundance, seasonal changes in numbers, and trends are poorly documented. This study, conducted from 2016 to 2024, presents the results of monthly and bimonthly wader censuses. Twenty-one species of waders were observed during this period, where the Ruddy Turnstone Arenaria interpres, Eurasian Whimbrel Numenius phaeopus, Grey Plover Pluvialis squatarola, Greater Sand Plover Anarhynchus leschenaultii and Common Greenshank Tringa nebularia were the most abundant. Peak numbers averaged 667 ± 103 individuals (range: 557–850) annually, with the central lagoon serving as the principal habitat (593 birds on average during peak months with a range of 194–885). The airstrip was the second most important site, with an average of 443 birds (range: 317–646), the most abundant species being the Ruddy Turnstone, with an average of 432 ± 110 individuals during peak periods. The wintering period of most species was between September and March, with some interspecific variations. Trend analysis indicated stable wader populations over the study period. Furthermore, the average numbers were comparable to counts made in the early 1990s, suggesting a long-term stability. These findings highlight the importance of Europa as a wintering site for palearctic waders in the western Indian Ocean despite its small size and remoteness
Des Savoirs Locaux à la Simulation : une Approche Intégrée pour anticiper les Impacts Climatiques sur les Tubercules du Pacifique
No full textInternational audienc
Drivers and impacts of sediment deposition in Amazonian floodplains
No full textInternational audienceThe Amazon River carries enormous amounts of sediment from the Andes mountains, much of which is deposited in its floodplains. However, accurate quantification of the sediment sink at fine spatiotemporal scales is still challenging. Here, we present a high-resolution hydrodynamic-sediment model to simulate sediment deposition in a representative Amazon/Solimões floodplain. The process is found to be jointly driven by inundation, suspended sediment concentration in the Amazon River, and floodplain hydrodynamics and only weakly correlated with inundation level. By upscaling the sediment deposition rate (1.33 ± 0.24 kg m −2 yr −1 ), we estimate the trapping of 77.3 ± 13.9 Mt (or 6.1 ± 1%) of the Amazon River sediment by the Amazon/Solimões floodplains every year. Widespread deforestation would reduce the trapping efficiency of the floodplains over time, exacerbating downstream river aggradation. Additionally, we show that the deposition of sediment-associated organic carbon plays a minor role in fueling carbon dioxide and methane emissions in the Amazon
Palabras en acción: sobre la contaminación en el franquismo y en la transición (1939-1978)
No full textPendiente de publicaciónInternational audienceEste trabajo pretende analizar un estudio semántico de las palabras que aparecieron dentro de lo que hoy llamamos “contaminación y medio ambiente.” Nos interrogaremos sobre qué palabras se emplearon para nombrar la “contaminación” y el “medio ambiente” y qué evoluciones existieron a lo largo del franquismo y la transición a la democracia. Esta evolución es importante porque asistimos a una época de cambio de régimen, pasando de una dictadura a un Estado más democrático que el régimen anterior. Por otro lado, en los países europeos y americanos la ecología y el medio ambiente comenzaron también a desarrollarse .Para ello, nos hemos basado en textos científicos, de peritaje, institucionales, para un estudio desde arriba. Y del mismo modo para un estudio desde abajo de estas evoluciones léxicas contamos con las protestas, boletines clandestinos, carteles y propaganda diversa producida por grupos sociales diferentes. Nuestra investigación se centra en investigaciones de archivos municipales, regionales y nacionales, así como en bibliotecas del mismo recorrido.A continuación, describiremos cuáles son los orígenes de la lexicografía usada en los inicios del industrialismo, a lo largo de los siglos XIX y XX. Después, analizaremos la semántica empleada bajo el franquismo y la evolución de esta hasta la transición
Derecho ambiental en las islas de la lealtad: cuestionando el éxito del mestizaje legal
No full textInternational audienceThe Loyalty Islands’ Environmental Code (New-Caledonia) seeks to merge French and Kanak views of nature. While Western naturalism separates humans and non-humans, Kanak animism sees continuity. Article 110-3 grants legal personality to natural elements, showing this ontological mix. However, France’s Council of State annulled key provisions, citing overreach into Caledonian civil law power. This reflects a clash between worldviews and highlights the limits of French environmental law in embracing alternative ontologies. The method used to carry out this study is combinatorial, combining the classic method of research in French law and a survey. The objective is to extract the essence of each vision by questioning the custodians of each
Observatoires Milieux-Sociétés et Données Géographiques: Enjeux Méthodologiques et Perspectives
No full textCet article présente un panorama méthodologique des observatoires scientifiques qui considèrent les dimensions milieux et sociétés de phénomènes sur des territoires d'étude et s'intègrent dans les systèmes de décisions territoriales. Il aborde et étudie les écosystèmes, les motivations, les cadres théoriques, les méthodologies et technologies mises en œuvre par ces observatoires orientés vers la modélisation des phénomènes spatio-temporels utiles à la décision. Nous étudions ces observatoires à partir des principes de représentation du temps et de l'espace dans les processus d'acquisition et de partage des données, leur contextualisation au regard de différentes modalités d'utilisation jusqu'aux interactions espace-temps société et leur mise en œuvre dans des applications environnementales et urbaines. Les progrès actuels de la recherche dans la mise en œuvre de ces observatoires et les problématiques encore ouvertes seront discutés
Ressources hydriques futures et sécheresses dans l’Atlas (Maroc) dans un scénario climatique à hautes émissions.
No full textInternational audienceUntersuchungsgebiet: Marokko, Nordafrika. Diese Studie untersucht 36 Gebirgs-Einzugsgebiete, die den Großteil des Oberflächenwassers des Landes bereitstellen.Ziel der Studie: Bewertung der potenziellen Auswirkungen des Klimawandels auf die Abflussverhältnisse in Marokko. Zwei hydrologische Modelle – World Wide HYPE und GR4J-CemaNeige – wurden in Kombination mit Ausgaben von neun bias-korrigierten regionalen Klimamodellen eingesetzt. Die zukünftigen Abflüsse wurden für ein Szenario mit hohen Emissionen (RCP8.5) für die Mitte des Jahrhunderts (2040–2060) und das Ende des Jahrhunderts (2070–2100) projiziert. Durch die Anwendung eines modernen Modellierungsansatzes an zahlreichen repräsentativen Standorten bietet die Studie einen robusten Rahmen zur Bewertung von Veränderungen hydrologischer Prozesse und der Wasserverfügbarkeit.Neue hydrologische Erkenntnisse für die Region: Die Ergebnisse zeigen deutliche Veränderungen in der Schneedynamik: Aufgrund steigender Temperaturen wird eine Abnahme des maximalen Schneespeichers um mehr als 50 % erwartet. Infolgedessen wird der Beitrag der Schneeschmelze zum Abfluss erheblich zurückgehen. Diese schneebedingten Veränderungen führen bis zum Ende des Jahrhunderts (2070–2100) zu einer durchschnittlichen Abflussreduktion von etwa −55 %. Diese Verringerung ist in erster Linie auf einen deutlichen Rückgang der Niederschläge (bis zu −43 %) in Verbindung mit einer starken Zunahme der potenziellen Evapotranspiration (bis zu +38 %) zurückzuführen. Darüber hinaus werden hydrologische Dürren häufiger und länger andauern, was die dringende Notwendigkeit von angepassten, einzugsspezifischen Wasserbewirtschaftungsstrategien unterstreicht.Study Region: Morocco, North Africa. This study examines 36 mountainous basins that supply most of the country's surface water. Study Focus: This study aims to evaluate the potential impacts of climate change on discharge in Morocco. Two hydrological models, World Wide HYPE and GR4J-CemaNeige, were used in combination with outputs from nine bias-corrected regional climate models. Future discharge was projected under the high-emission RCP8.5 scenario for the mid-century (2040-2060) and late-century (2070-2100). By implementing a state-of-the-art modeling approach on numerous representative sites, the study provides a robust framework for assessing changes in hydrological processes and water availability. New Hydrological Insights for the Region: This research identifies critical changes in snow dynamics, with peak snow storage projected to decrease by over 50 % due to rising temperatures. Consequently, the contribution of snowmelt to discharge will significantly diminish. These snow-related shifts are heading to an average reduction in discharge of − 55 % by the late century (2070-2100). This reduction is primarily driven by significant decreases in precipitation (up to − 43 %) combined with substantial increases in potential evapotranspiration (up to +38 %). Additionally, hydrological droughts are expected to become more frequent and prolonged, underscoring the urgent need for adaptive water management strategies specifically designed to address basin-specific characteristics.Région d’étude : Maroc, Afrique du Nord. Cette étude porte sur 36 bassins versants montagneux qui fournissent l’essentiel des ressources en eau de surface du pays.Objectif de l’étude : Évaluer les impacts potentiels du changement climatique sur les débits au Maroc. Deux modèles hydrologiques, World Wide HYPE et GR4J-CemaNeige, ont été utilisés en combinaison avec les sorties de neuf modèles climatiques régionaux corrigés du biais. Les débits futurs ont été projetés selon le scénario d’émissions élevées RCP8.5, pour la moitié du siècle (2040-2060) et la fin du siècle (2070-2100). En appliquant une méthodologie de modélisation de pointe sur un large ensemble de sites représentatifs, l’étude offre un cadre robuste pour évaluer les changements des processus hydrologiques et de la disponibilité en eau.Nouveaux éclairages hydrologiques pour la région : Cette recherche met en évidence des changements critiques dans la dynamique de la neige, avec une diminution de plus de 50 % du stockage neigeux maximal en raison de l’augmentation des températures. Par conséquent, l’apport de la fonte nivale aux débits diminuera fortement. Ces modifications liées à la neige devraient entraîner une réduction moyenne des débits d’environ −55 % d’ici la fin du siècle (2070-2100). Cette baisse est principalement due à une diminution marquée des précipitations (jusqu’à −43 %) combinée à une augmentation substantielle de l’évapotranspiration potentielle (jusqu’à +38 %). Par ailleurs, les sécheresses hydrologiques deviendront plus fréquentes et plus prolongées, soulignant l’urgence d’adopter des stratégies de gestion de l’eau adaptées aux spécificités de chaque bassin
Utilisation des technologies numériques par les adolescents pour la santé : aperçus de la Nouvelle-Calédonie
No full textInternational audienceINTRODUCTION: Adolescents worldwide increasingly use digital technology (eg. online platforms) for health. With limited evidence from the Pacific Islands Countries and Territories, it is crucial to understand how adolescents in these regions use online platforms for health. By examining their patterns of use and reasons for engagement, effective educational initiatives and interventions tailored to their needs can be developed.OBJECTIVES: This cross-sectional study aimed to explore the use of digital technology for health by adolescents in New Caledonia.METHODOLOGY: Participants used classroom computers to complete an online questionnaire through RedCap. Data was collected in Noumea and Lifou in 2023 by researchers from the University of Sydney and the University of New Caledonia. Classes were selected based on teacher interest and consent. RESULTS: Year 7 and 8 students (mean= 12.8 years) from 3 schools participated, collecting 144 responses on their digital technology use for health. Findings reveal that participants owned social media accounts for TikTok (73.2%), Instagram (61.9%), Snapchat (54.2%), Facebook (52.8%), and YouTube (52.1%). Participants used apps, social media, or websites (31.7%) to search health information. Important factors when using a health-related app or website are that it is free (75.5%) and easy to use (66.6%). Participants trust content from a government website (45.7%), someone they trust (41.5%), or if recommended by a teacher or community leader (35.9%). Almost half (42.3%) reported not checking the accuracy of the information. Other participants ask friends or family (38.0%), check other online sources (35.9%), or other social media platforms (20.4%). Participants (48.9%) reported that using social media helped them make changes to their health.CONCLUSION: Almost 1/3 of young adolescents use online platforms to search and discuss health information, prioritising social media that are freely accessible, acknowledging some benefits to their health. Our findings add to the growing body of evidence of digital health in New Caledonia and identify key information to tailor the development of interventions that resonate with specific needs in a Pacific context. This evidence may enhance the overall health outcomes of adolescents and improve their digital health literacy, empowering them to effectively navigate and use digital health resources