What environmental and human factors influence the decision of a beachgoer to enter the water at a high-energy beach? Application to South Western France
Background Coastal areas are among the most attractive destinations worldwide, but engaging in water-based recreational activities is not without risk. The overall bathing risk ultimately results from the combination of natural physical hazards (e.g. rip currents, shore break waves) and the individuals who expose themselves to them. Among the growing body of beach safety studies, many have identified the lack of exposure data as a severe limitation (1). A first attempt to address this was made by considering the beachgoer population rather than the total population to assess incident rates (2). We believe our research takes a step further by estimating the proportion of beachgoers who enter the water on a given day. Methods We built a unique multidisciplinary database combining data collected by an on-site beachgoers survey, weather stations, marine buoys and tidal reconstruction. We employed a logistic regression analysis to predict beachgoer’s decision to enter the water on any given day at a high-energy recreational beach. Results We demonstrated that both environmental and human factors influence a beachgoer’s decision to enter the water. Daily mean wave height and daily mean insolation duration were significant predictors at the p<0.001 level, while age, place of residence and self-confidence in swimming out of a rip current were significant at the p<0.05 level or higher. Our model has an accuracy, F-Score, precision and recall of 71%, 73%, 86%, 79% respectively. Conclusion Beachgoer exposure on any given day can ultimately be predicted by coupling our model with beach attendance models (3). This would allow for the design of rescue and preventive operations on days with high expected exposure. While models based solely on environmental factors can be used to forecast beach risks, incorporating human factors into the model provides valuable insight for crafting prevention messages. To this end, forecasting tools must be based on behavioural analytical framework as much as possible
(20/11/2025)
UR ETTIS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Consistent response of European summers to the latitudinal temperature gradient over the Holocene
The drivers behind the current decadal trend toward longer and more extreme European summers are widely discussed. This is attributed to changes in the mid-latitude summer atmospheric circulation in response to Arctic Amplification and weakening of the latitudinal temperature gradients (LTGs), as well as to reduced aerosol emissions over Europe since the 1980s. However, causal links remain uncertain, limiting confidence in future projections. To gain statistical insights, evidence over periods longer than the instrumental record is necessary. Using seasonally resolved lake sediments, we reconstruct the evolution of the European summer-to-annual ratio over the last ten millennia. Our results indicate that summer weather dominated during the mid-Holocene, with an average of 195 summer days per year-falling within the extreme upper tail of summer distributions in the early-and late-Holocene. The Holocene variability in summer days aligns closely with simulated past changes in the LTG, supporting the hypothesis that dynamical processes influence midlatitude seasonal weather on decadal to millennial timescales. A 1 °C decrease in LTG would extend the summer season by ~6 days, potentially adding up to 42 summer days by 2100 under a business-as-usual scenario. These findings provide key observational constraints for understanding and projecting seasonal impacts on ecosystems and society.
The annual cycle of atmospheric circulation and associated weather regimes establishes the climate seasonal clock by determining the characteristic timing and recurrence of seasonal conditions. In the North Atlantic (NA)-European region, atmospheric circulation is prevailed by westerlies that transport heat and moisture from the ocean to the continent, thereby reducing the ocean-land surface temperature gradient and exerting a strong influence on the mean European climate. Additionally, a persistent high-pressure system over northern Europe, the so-called Scandinavian Blocking (SB), can divert the jet stream, creating a meandering, meridional flow and leading to prolonged climate extremes 1,2 (Fig. 1). According to the relationship between daily sea level pressure and continental temperature, the European climate seasonal clock is divided into two main seasons: summer and winter 2 . The onset of each season is determined by the
(Nature Communications. vol. 16, n° 2041-1723, 19/11/2025)
RHUL, UDC, GKT, ASTRAL, IMB, UB, Bordeaux INP, CNRS, Inria, UB, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
From Fields to Homes: How Agricultural Pesticides Contaminate Residential Environments? Findings from the PESTIPREV Study, France
Pesticide sprayings on crops can contaminate nearby homes, yet factors driving pesticide penetration indoors remain poorly understood. Our objective was to study the influence of factors related to air exchange and occupants track-in on agricultural pesticide surface loadings (SLs) measured in homes near vineyards. Indoor surface wipes were collected in 31 homes near vineyards during the peak pesticide application season in 2020 and 2021 and analyzed via LC/MS/MS or GC/MS/MS. Questionnaire data provided information on air exchange and track-in factors. Linear mixed models assessed their effects on SLs of seven fungicides across all surfaces (n = 667) and stratified by recently cleaned surfaces (n = 217), floors (n = 105), and high dusty surfaces (n = 130). Daytime airing reduced floor SLs by 14–28%, depending on the pesticide, but increased SLs by up to 38% on high surfaces. Nighttime airing was associated with a 20–65% increase in recently cleaned surface SLs. Double-flow ventilation increased high surface SLs by 21–126%, while ventilation grids reduced contamination, especially on floors (up to 51%). Home insulation tended to raise SLs. Pets and gardening were the main sources of pesticide track-in, contributing to an 11–87% increase in floor SLs. However, pets substantially reduced SLs on high surfaces. Direct yard access increased SLs in rooms by 5–10%. Room occupancy and outdoor activities showed mixed effects depending on the surface, whereas shoe removal and doormat use showed no significant impact. While ventilation effects remain complex to interpret for prevention, track-in findings suggest hygiene measures could help reduce indoor pesticide SLs.
(Water, Air, and Soil Pollution. vol. 237, n° 0049-6979, pp. article no 150, 19/11/2025)
BPH, UB, INSERM, CHU Bordeaux, ARS Nouvelle-Aquitaine, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOSYS, INRAE
CartoRUM : outil de calcul et de cartographie du réservoir en eau utilisable maximal des sols à partir des bases de données au format DoneSol
La disponibilité de données sur les sols augmente en France, notamment par l’effort de réalisation des Référentiels Régionaux Pédologiques (RRP) dans le cadre du programme « Inventaire, Gestion et Conservation des Sols » (IGCS) coordonné par le Groupement d’intérêt Scientifique Sol. Ces systèmes d’informations spatialisées sur les sols à l’échelle 1/250 000 présentent une base sémantique riche qui peut être valorisée à travers des cartographies thématiques de propriétés fonctionnelles des sols à l‘échelle régionale. Dans ce contexte, notre étude vise à proposer une procédure pour calculer et cartographier aisément et de façon quasi-automatique le Réservoir en eau Utilisable (RU) des sols à partir d’un RRP, sous la forme d’un un script en langage Python.
(18/11/2025)
SAS, INRAE, Institut Agro, Institut Agro, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Bordeaux Sciences Agro
One-year high-frequency environmental and behavioral data from ALAN experience in a French coastal area
Despite the widespread exposure to artificial light at night (ALAN) on coastal ecosystems, its effects are poorly studied, and data remain scarce compared to terrestrial ecosystems. Coastal areas are critical for ecosystem services, providing biodiversity, social, and commercial benefits. To acquire high-quality data on ALAN impacts on coastal ecosystems, we conducted a one-year in situ study in the “Ile aux Oiseaux” site, part of the Arcachon Bay (France), from December 2023 to November 2024. The experimental platforms consisted of two oyster tables: one for the control condition exposed to natural light and one exposed to a skyglow ALAN intensity using underwater LEDs. The impacts of ALAN were assessed using two oyster species (Crassostrea gigas and Ostrea edulis) as sentinel organisms, recording continuously their valve behavior using high-frequency non-invasive valvometer biosensors. To characterize the local environment, the experimental platform was also equipped with multiple sensors for the long-term measurement of light irradiance and additional physical parameters (temperature, water level, salinity, turbidity, conductivity, and low-frequency sound).
(Scientific Data. vol. 12, pp. 1808, 18/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEODE, UT2J, Comue de Toulouse, CNRS
Cartographie des fonctions biogéochimiques de l’estuaire de la Seine à partir de données de télédétection
(18/11/2025)
LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, Nantes Univ, i-Sea, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, ECOBIO, UR, INEE-CNRS, CNRS, CNRS, OZHM, UMR TETIS, Cirad, CNRS, INRAE
Comparaison de bioindicateurs du fonctionnement écologique des vasières pour guider leur restauration
(18/11/2025)
MERSEA, UNICAEN, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, SBR, SU, CNRS, CSLN
Shallow benthic invertebrate communities in relation to substrate types in coastal environments of the sub-Antarctic Crozet archipelago.
Coastal ecosystems of sub-Antarctic islands are threatened by increasing climate-driven changes and direct anthropogenic pressures. Significant effects on marine communities are expected, but benthic ecosystems of these isolated islands remain largely under-explored. Effective preservation of these nearshore environments requires deeper ecological assessments and comprehensive biodiversity knowledge. In this regard, this study reports findings from a survey carried out in 2021 at two sites – Baie du Marin and Crique du Sphinx – located on the eastern coast of Ile de la Possession (sub-Antarctic Crozet archipelago, Southern Ocean). We investigated the composition and structure of nearshore benthic faunal communities using a quantitative fieldwork protocol and an integrative molecular- and morphology-based taxonomic approach. A total of 124 morphotypes were identified, including a high proportion (72%) of rare species. Both sites exhibited similar benthic invertebrate communities. Structurally complex habitats such as hard substrates or areas dominated by macroalgae exhibited higher species richness and diversity. The investigated benthic invertebrate communities are typical of the sub-Antarctic area but featured unique structures, including dense tube-dwelling polychaete colonies. This study will provide a baseline for future monitoring programs and for the preservation of sub-Antarctic coastal benthic ecosystems.
(Frontiers in Marine Science. vol. 12, n° 2296-7745, pp. 1692217, 14/11/2025)
BGS, EPHE, PSL, CNRS, UBE, LBM, ULB, LECOB, SU, CNRS, OOB, SU, CNRS, ULiège, ULiège, NUI Galway, UMAG, CHIC, BASE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMR, UiB, UIB, UAM
Développement de nouveaux algorithmes d’apprentissage statistique pour coupler projections climatiques et observations passées en vue de réduire les incertitudes du changement climatique à venir
Le climat change à cause des émissions humaines de gaz à effet de serre. Les modèles climatiques permettent de projeter son évolution selon des scénarios futurs d’émissions humaines (SSP). Cependant, les résultats des différents modèles climatiques développés dans le monde sont quantitativement divergents, générant une grande incertitude appelée par la suite incertitude modèle.Cette incertitude modèle est particulièrement forte pour la circulation méridienne de retournement en Atlantique (AMOC), un système de courants océaniques qui affecte les conditions climatiques de nombreuses régions du globe. En effet, même si tous les modèles climatiques CMIP6 prévoient un ralentissement de l’AMOC, l’ampleur varie fortement : en moyenne, ils projettent un ralentissement AMOC de 33 ± 36% d’ici 2100 (confiance 90%, scénario SSP2-4.5).Pour réduire l’incertitude modèle, les méthodes dites de contraintes observationnelles (COs) ont été récemment développées. Elles contraignent les projections des modèles par l'observation réelle d'une (univarié) ou de plusieurs (multivarié) variables. Ces approches sont cependant difficiles à utiliser car dans la littérature (i) les fondements statistiques sur lesquels elles reposent ne sont pas toujours identiques et manquent souvent de clarté, (ii) les approches sont très diversifiées et souvent univariées, et (iii) le choix des variables observables est subjectif. Cette thèse se compose de trois articles qui traitent chacune de ces trois problématiques.(i) Le premier article propose un modèle statistique rigoureux pour une CO linéaire multivariée, appelé ClimLoco1.0. Il prend en compte l’incertitude sur l'observation réelle et l'incertitude provenant du nombre limité de modèles climatiques, toutes deux souvent négligées ou mal considérées dans la littérature. Dans un souci de pédagogie, l’article détaille progressivement la construction de ClimLoco1.0 et fournit des interprétations graphiques des résultats mathématiques obtenus.(ii) Le second article compare les performances de quatre approches de CO, par validation croisée. L’AMOC future y est contrainte soit par l’AMOC passée (univarié), soit par l’AMOC passée, la température et la salinité de surface de différentes régions océaniques choisies subjectivement (multivarié). L’approche la plus performante est la régression Ridge dans le cas multivarié, qui est particulièrement adaptée à notre étude. Elle fournit une estimation du ralentissement AMOC d’ici 2100 de 51 ± 8% (SSP2-4.5). Ce ralentissement plus important que celui estimé par la moyenne multi-modèle (33%) résulte principalement de la considération du biais des modèles climatiques concernant la salinité de surface en Atlantique sud. Cela est en accord avec la littérature reliant ce biais à la rétroaction positive d’advection de salinité, un mécanisme clé pour la stabilité de l’AMOC.(iii) Le troisième article utilise une méthode spécifique de clustering pour créer des groupes de régions associées à de nombreuses variables climatiques. Ces groupes sont interprétés pour identifier les mécanismes qui expliquent l’incertitude modèle de l’AMOC future. Ils sont également résumés par des variables synthétiques qui sont utilisées dans la méthode ClimLoco1.0 pour contraindre cette incertitude modèle. Cette méthode suggère que l’incertitude modèle est notamment expliquée par la rétroaction positive d’advection de salinité et les remontées d’eaux profondes, en accord avec la littérature. Contrainte par l’observation de ces variables synthétiques, l'estimation du ralentissement AMOC d'ici 2100 est de 45 ± 10% (SSP2-4.5).Les deux derniers articles estiment un ralentissement AMOC similaire, qui est plus important et moins incertain que celui estimé par la simple moyenne multi-modèles. Il semble donc opportun que ce résultat soit pris en compte afin d’améliorer les projections climatiques et les stratégies d'adaptation associées.
(14/11/2025)
ASTRAL, IMB, UB, Bordeaux INP, CNRS, Inria, UB, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Global Carbon Budget 2025
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesise datasets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy statistics and cement production data. Emissions from land-use change (ELUC) are estimated by bookkeeping models based on land-use and land-use change data. Atmospheric CO2 concentration is measured at surface stations, and the global atmospheric CO2 growth rate (GATM) is computed from the annual changes in concentration. The global net uptake of CO2 by the ocean (SOCEAN, called the ocean sink) is estimated with global ocean biogeochemistry models and observation-based fCO2products. The global net uptake of CO2 by the land (SLAND, called the land sink) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, ocean interior observation-based estimates, and Earth System Models. The sum of all sources and sinks results in the carbon budget imbalance (BIM), a measure of imperfect data and incomplete understanding of the contemporary of 2023-2024 in the Northern Hemisphere. The ocean CO2 sink was 3.2 ± 0.4 GtC yr -1 during
(13/11/2025)
CICERO, UiO, UEA, GKSS, VLIZ, MPI-M, WUR, LMU, LMU, LMU, CSIRO, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, BIOGEO, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, UiO, PMEL, NOAA, KIT, CIMAS, RSMAS, BIOS, UOR, MFRI, BSC-CNS, LMD, INSU - CNRS, X, IP Paris, SU, CNRS, ENS-PSL, PSL, ENPC, IP Paris, CSIRO, JAMSTEC, SATINV, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, JMA, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS