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The data contains three supporting datasets: 1. Mid-intertidal data 2. Vertical transect data 3. GPS coordinates for all sites

# Long-term changes in taxonomic and functional composition of European marine fish communities The GitHub linked repository is here: [European_demersal_fish_assemblages (](https://github.com/auroreRECE/European_demersal_fish_assemblages)DOI [10.5281/zenodo.11190119](https://zenodo.org/doi/10.5281/zenodo.11190119)) ## Overview This project is dedicated to studying the influence of environmental conditions and fishing on the functional and taxonomic structure of a demersal fish community in Europe. This GitHub repository provides the code of the Receveur et al. (2024) publication in Ecography. ## Data files description ### df\_MFA.csv This file contains the coordinates resulting from the Multiple Factor Analysis (MFA): * X : the row numbers ; * ID_unique : a unique ID number corresponding to the trawls ; * Dim.1 : the coordinate of each trawl on the first MFA dimension ; * Dim.2 : the coordinate of each trawl on the second MFA dimension ; * Dim.3 : the coordinate of each trawl on the third MFA dimension ; ### df\_PCA.csv This file contains the coordinates * X : the row numbers ; * ID_unique : a unique ID number corresponding to the trawls ; * Dim.1 : the coordinate of each trawl on the first PCA dimension ; * Dim.2 : the coordinate of each trawl on the second PCA dimension ; * Dim.3 : the coordinate of each trawl on the third PCA dimension ; ### df\_env.csv This file contains the following environmental parameters: * X : the row numbers ; * ID_unique : a unique ID number corresponding to the trawls ; * Year : the Year of each trawl ; * Quarter : the Quarter of each trawl ; * Ecoregion : the Ecoregion where each trawl has been done; * Survey : the name of the Survey ; * x_my_spatial_id : the longitude of the ICES rectangle where the trawl has been done ; * y_my_spatial_id : the latitude of the ICES rectangle where the trawl has been done ; * my_spatial_id : an ID for the ICES rectangle where the trawl has been done ; * depth : the bottom depth (meters) ; * depth_span : the bottom depth variability (maximum depth of the ICES cell - minimum depth) (meters) ; * chloro_mea: the mean chlorophyll-a concentration (mg/m³) ; * mlotst_mea : the mean mixed layer depth (meters) ; * oxy_bottom_mea : the mean bottom dissolved oxygen (umol/l) ; * oxy_surf_mea : the mean surface dissolved oxygen (umol/l) ; * temp_bottom_mea : the mean bottom temperature (°C) ; * temp_surf_mea : the mean surface temperature (°C) ; * curr_surf_mea : the mean surface current strength (m/s) ; * curr_bottom_mea : the mean bottom current strength (m/s) ; * sal_surf_mea : the mean surface salinity (PSU) ; * chloro_std : the standard deviation of chlorophyll-a concentration (mg/m³) ; * mlotst_std : the standard deviation of mixed layer depth (meters) ; * oxy_bottom_std : the standard deviation of bottom dissolved oxygen (umol/l) ; * oxy_surf_std : the standard deviation of surface dissolved oxygen (umol/l) ; * temp_bottom_std : the standard deviation of bottom temperature (°C) ; * temp_surf_std : the standard deviation of surface temperature (°C) ; * curr_surf_std : the standard deviation of surface current strength (m/s) ; * curr_bottom_std : the standard deviation of bottom current strength (m/s) ; * sal_surf_std : the standard deviation of surface salinity (PSU). ## Raw Data sources ### Biological data Trawls content is publicly available for the North East Atlantic (DATRAS database). Mediterranean data (MEDITS database) are available upon request to Maritime Affairs and Fisheries (MARE DATACOLLECTIONFRAMEWORK). The project uses the following surveys: | Survey Code | Survey name | Area | Period | References | | :---------- | :----------------------------------------------------- | :------------------------------------- | :-------: | :--------: | | BITS | Baltic International Trawl Survey | Baltic Sea | 1994-2019 | 4 | | BTS | Beam Trawl Survey | Celtic Sea; English Channel; North Sea | 1997-2019 | 7 | | BTS-VIII | Beam Trawl Survey – Bay of Biscay | Bay of Biscay | 2011-2019 | 7 | | DWS | Deepwater Survey | Irish Sea | 2006-2007 | 8 | | DYFS | Inshore Beam Trawl Survey | Southern North Sea | 2002-2019 | 7 | | EVHOE | French Southern Atlantic Bottom trawl Survey | Bay of Biscay and Celtic Sea | 2003-2019 | 1 | | FR-CGFS | French Channel ground Survey | English Channel | 1997-2019 | 2 | | IE-IAMS | Irish Anglerfish and megrim Survey | Scottish rockall and Irish Sea | 2016-2019 | 2 | | IE-IGFS | Irish Groundfish | Ireland Shelf Sea | 2003-2019 | 2 | | MEDITS | International bottom trawl survey in the Mediterranean | Mediterranean Sea | 1994-2018 | 9 | | NIGFS | Northern Ireland Groundfish Survey | Irish Sea | 2009-2019 | 2 | | NS-IBTS | North Sea International Bottom Trawl Survey | North Sea | 1997-2019 | 2 | | PT-IBTS | Portuguese International Bottom Trawl Survey | Portugal Shelf Sea | 2003-2017 | 2 | | ROCKALL | Scottish Rockall Survey (until 2010) | Rockall plateau | 2003-2009 | 2 | | SCOROC | Scottish Rockall Survey (from 2011) | Scottish plateau | 2011-2019 | 2 | | SCOWCGFS | Scottish West Coast Groundfish Survey | Scottish west coast | 2011-2019 | 2 | | SNS | Sole Net Survey | Southern North Sea | 2002-2019 | 7 | | SP-ARSA | Spanish Gulf of Cadiz Bottom Trawl Survey | Spain | 2003-2019 | 6 | | SP-NORTH | Spanish North Bottom Trawl Survey | North of Spain | 2003-2019 | 2 | | SP-PORC | Spanish Porcupine Bottom Trawl Survey | Irish Sea | 2003-2019 | 5 | | SWC-IBTS | Scottish West Coast International Bottom Trawl Survey | Scotland Shelf Sea | 1999-2010 | 2 | ### Trait data The complete traits data table is available upon request. It is a combination of the publicly available PANGAEA database, Fishbase information, and inference based on the FISHLIFE project. ### Environmental variables The data used are all publicly available on the Copernicus website. ### Fishing data The data used are all publicly available on the Global Fishing Watch website. ## Recommended Citation Please use the following citation: Receveur, A., Leprieur F., Ellingsen K., Keith D., Kleisner K., McLean M., Mérigot B., Mills K., Mouillot D., Rufino M., Trindade-Santos I., Van Hoey G., Albouy C., Auber A. Data for “Long-term changes in taxonomic and functional composition of European marine fish communities.” Dryad Digital Repository. (2024). doi.org/10.5061/dryad.x69p8czsj ## Acknowledgments This research is a product of the MAESTRO group funded by the synthesis center CESAB of the French Foundation for Research on Biodiversity (FRB). We thank France Filière Pêche (FFP) who founded the MAESTRO project. We also warmly thank all those who have contributed in any way to the scientific surveys and data collection/provision (European Institutions and scientists implicated in DATRAS-BTS, MEDITS, and DCF). ## References 1. ICES. The EVHOE survey (France). ICES Documents. (1997). Available at: https://archimer.ifremer.fr/doc/00036/14707/12013.pdf 2. ICES. Manual of the IBTS North Eastern Atlantic Surveys. Series of ICES Survey Protocols SISP 15 (2017). doi:10.17895/ices.pub.3519 3. ICES. Manual for the International Bottom Trawl Surveys Revision VIII. Series of ICES Survey Protocols SISP 10 - IBTS IX. (2015). 4. https://ices-library.figshare.com/articles/report/SISP_7_-*Manual_for_the_Baltic_International_Trawl_Surveys_BITS*/19050986 5. https://gis.ices.dk/geonetwork/srv/api/records/ce94a257-c8b3-44f7-9fd0-6bd7449ce073 6. http://ices.dk/sites/pub/CM%20Doccuments/2002/D/D0302A.pdf 7. https://ices-library.figshare.com/articles/report/SISP_14_-*Manual_for_the_Offshore_Beam_Trawl_Surveys_WGBEAM*/19051328 8. https://gis.ices.dk/geonetwork/srv/api/records/936b4fb7-9baa-4dbc-abd0-b1b7bda16406 9. https://archimer.ifremer.fr/doc/00117/22783/20585.pdf Evidence of large-scale biodiversity degradation in marine ecosystems has been reported worldwide, yet most research has focused on few species of interest or on limited spatiotemporal scales. Here we assessed the spatial and temporal changes in the taxonomic and functional composition of fish communities in European seas over the last 25 years (1994-2019). We then explored how these community changes were linked to environmental gradients and fishing pressure. We show that the spatial variation in fish species composition is more than two times higher than the temporal variation, with a marked spatial continuum in taxonomic composition and a more homogenous pattern in functional composition. The regions warming the fastest are experiencing an increasing dominance and total abundance of r-strategy fish species (lower age of maturity). Conversely, regions warming more slowly show an increasing dominance and total abundance of K-strategy species (high trophic level and late reproduction). Among the considered environmental variables, sea surface temperature, surface salinity, and chlorophyll-a most consistently influenced communities’ spatial patterns, while bottom temperature and oxygen had the most consistent influence on temporal patterns. Changes in communities’ functional composition were more closely related to environmental conditions than taxonomic changes. Our study demonstrates the importance of integrating community-level species traits across multi-decadal scales and across a large region to better capture and understand ecosystem-wide responses and provides a different lens on community dynamics that could be used to support sustainable fisheries management.

Project: GCOS Earth Heat Inventory - A study under the Global Climate Observing System (GCOS) concerted international effort to update the Earth heat inventory (EHI), and presents an updated international assessment of ocean warming estimates, and new and updated estimates of heat gain in the atmosphere, cryosphere and land over the period from 1960 to present. Summary: The file “GCOS_EHI_1960-2020_Earth_Heat_Inventory_Ocean_Heat_Content_data.nc” contains a consistent long-term Earth system heat inventory over the period 1960-2020. Human-induced atmospheric composition changes cause a radiative imbalance at the top-of-atmosphere which is driving global warming. Understanding the heat gain of the Earth system from this accumulated heat – and particularly how much and where the heat is distributed in the Earth system - is fundamental to understanding how this affects warming oceans, atmosphere and land, rising temperatures and sea level, and loss of grounded and floating ice, which are fundamental concerns for society. This dataset is based on a study under the Global Climate Observing System (GCOS) concerted international effort to update the Earth heat inventory published in von Schuckmann et al. (2020), and presents an updated international assessment of ocean warming estimates, and new and updated estimates of heat gain in the atmosphere, cryosphere and land over the period 1960-2020. The dataset also contains estimates for global ocean heat content over 1960-2020 for different depth layers, i.e., 0-300m, 0-700m, 700-2000m, 0-2000m, 2000-bottom, which are described in von Schuckmann et al. (2022). This version includes an update of heat storage of global ocean heat content, where one additional product (Li et al., 2022) had been included to the initial estimate. The Earth heat inventory had been updated accordingly, considering also the update for continental heat content (Cuesta-Valero et al., 2023).

Human-induced climate change is causing significant harm to our oceans, with ocean acidification, warming, and deoxygenation posing fundamental threats to marine life and ultimately, human societies (Gruber, 2011; Schubert et al., 2006). These processes provide specific threats to marine ecosystems and increase the possibility of crossing tipping points: “critical thresholds beyond which a system reorganizes, often abruptly and/or irreversibly” (IPCC, 2022)a. Once crossed, physical, chemical, and biological, changes may result in food web reorganisations and regime shifts triggering. These regime shifts, although regional, may add up to a problem of global dimensions for natural resources and human well-being. To address these issues, the H2020 COMFORT project focused on investigating tipping points in the Earth system, specifically in relation to acidification, warming, and deoxygenation processes. The project aimed to assess safe operating spaces, mitigation pathways, and future scenarios. In this document, we present key findings from the COMFORT project and complement them with available literature on human-induced impacts on marine ecosystems, particularly in the Arctic, Atlantic, Pacific, and Southern Oceans, as well as in three European seas: the Mediterranean, Baltic, and North Sea.

The Arctic, and Svalbard in particular, is experiencing a more rapid warming compared to the global average. Such Atlantification of the Arctic may change food webs in a way that can also affect the contaminant levels in top predators such as seabirds. Studies have found that the black-legged kittiwake (Rissa tridactyla) in Kongsfjorden, Svalbard, has changed its diet from mainly Arctic prey items towards a more mixed diet with contribution from Atlantic species since 2007. Atlantic species might function as biovectors, bringing contaminants into the Arctic from more contaminated areas. However, Arctic species might have a higher contaminant load, due their high lipid content. My thesis explored if changes observed in dietary ecology, using two different approaches, can explain variability in black-legged kittiwake exposure to organochlorine contaminants during the years 2007-2020, here represented by seven compounds including polychlorinated biphenyl (PCB) 99, PCB 153, PCB 180, β-hexachlorocyclohexane, hexachlorobenzene, p,p’- dichlorodiphenyldichloroethylene (DDE), and oxychlordane. Dietary ecology was quantified by both frequency of occurrence of diet items and groups from regurgitate samples and by stable isotope analysis. Stable nitrogen isotope values (δ 15N) have been established as a proxy for trophic position, and stable carbon isotope values (δ 13C) indicate foraging habitat and primary carbon source. Annual variation in frequency of occurrence of prey species (or groups) did not explain the variation in either δ 13C or δ 15N values. There were significant differences in the annual variations in contaminants levels, but there was no clear temporal trend for any contaminants during the study period. Model selection showed that neither diet items nor stable isotope values explained the variation in contaminant levels. Instead, the null-model, with year as a random effect factor, was often ranked as a strong model. However, some variables, such as trophic level, carbon source and frequency of occurrence ...

Surface–atmosphere energy exchange is strongly ecosystem-specific. At the same time, as the energy balance constitutes responses of an ecosystem to environmental stressors including precipitation, humidity and solar radiation, it results in feedbacks of potential importance for the regional climate. Northern peatlands represent a diverse class of ecosystems that cover nearly 6 × 106 km2 in the Boreal region, which makes the inter-comparison of their energy balances an important objective. With this in mind we studied energy exchange across a broad spectrum of peatlands from pristine fens and bogs to forested and agriculturally managed peatlands, which represent a large fraction of the landscape in Finland and Sweden. The effects of management activities on the energy balance were extensively examined from the micrometeorological point of view, using eddy covariance data from eight sites in these two countries (56º 12'–62º 11' N, 13º 03'–30º 05' E). It appears that the surface energy balance varies widely amongst the different peatland types. Generally, energy exchange features including the Bowen ratio, surface conductance, coupling to the atmosphere, responses to water table fluctuations and vapour pressure deficit could be associated directly with the peatland type. The relative constancy of the Bowen ratio in natural open mires contrasted with its variation in tree-covered and agricultural peatlands. We conclude that the impacts of management and the consequences of land-use change in peatlands for the local and regional climate might be substantial.

The report gives an overview of the actual oceanographic data and the corresponding metadata included in the CoCoNET database (ftp://ismar.cnr.it). NERSC Technical Report no. 348 (B). CoCoNet Deliverable 11.11

Résumé. Dans chaque cycle d'évaluation du GIEC, une multitude de scénarios sont évalués, avec une portée et une importance différentes dans les différents groupes de travail et rapports spéciaux et leurs chapitres respectifs. Dans les rapports, l'ambition est d'intégrer les connaissances sur les futurs climatiques possibles dans les groupes de travail et les domaines de recherche scientifique sur la base d'un petit ensemble de « voies de cadrage », telles que les voies dites RCP du cinquième rapport d'évaluation du GIEC (AR5) et les scénarios SSP-RCP dans le sixième rapport d'évaluation (AR6). Cette perspective, initiée par les discussions lors de l'atelier du GIEC à Bangkok en avril 2023 sur « l'utilisation des scénarios dans le RE6 et les évaluations ultérieures », est destinée à servir d'une des contributions de la communauté pour mettre en évidence les besoins pour la prochaine génération de voies de cadrage qui est avancée sous l'égide du CMIP pour une utilisation dans le RE7 du GIEC. Ici, nous suggérons un certain nombre d'objectifs de recherche politique qu'un tel ensemble de voies d'encadrement devrait idéalement remplir, y compris les besoins d'atténuation pour atteindre les objectifs de l'Accord de Paris, les risques associés aux stratégies d'élimination du carbone, les conséquences du retard dans la mise en œuvre de cette atténuation, des conseils pour les besoins d'adaptation, les pertes et les dommages, et pour la réalisation de l'atténuation dans le contexte plus large des objectifs de développement sociétal. Sur la base de ce contexte, nous suggérons que la prochaine génération de scénarios climatiques pour les modèles du système terrestre évolue vers des « voies d'émission représentatives » (REP) et suggérons des catégories clés pour ces voies. Ces « voies d'encadrement » devraient répondre aux besoins les plus critiques en matière de politique d'atténuation et d'adaptation au cours des 5 à 10 prochaines années. À notre avis, les catégories les plus importantes sont celles qui sont pertinentes dans le contexte de l'objectif à long terme de l'Accord de Paris, en particulier une action immédiate (dépassement faible) de 1,5 °C et une action retardée (dépassement élevé) de 1,5 °C. Deux autres catégories clés sont une catégorie de trajectoire approximativement conforme aux objectifs politiques actuels (tels qu'exprimés d'ici 2023) à court et à long terme, et une catégorie d'émissions plus élevées qui est approximativement conforme aux « politiques actuelles » (telles qu'exprimées d'ici 2023). Nous plaidons également en faveur de la pertinence scientifique et politique de l'exploration de deux « mondes qui auraient pu l'être ». L'une de ces catégories a des trajectoires d'émissions élevées bien au-dessus de ce que les politiques actuelles impliquent, et l'autre a des trajectoires d'émissions très faibles qui supposent que les mesures d'atténuation mondiales visant à limiter le réchauffement à 1,5 °C sans dépassement ont commencé en 2015. Enfin, nous notons que la fourniture en temps opportun de nouvelles informations scientifiques sur les voies est essentielle pour éclairer l'élaboration et la mise en œuvre de la politique climatique. Pour le deuxième bilan mondial dans le cadre de l'Accord de Paris en 2028, et pour éclairer le développement ultérieur des contributions déterminées au niveau national (CDN) jusqu'en 2040, des contributions scientifiques sont nécessaires bien avant 2028. Ces besoins doivent être soigneusement pris en compte dans le calendrier d'élaboration des activités de modélisation communautaire, y compris celles menées dans le cadre du CMIP7. Resumen. En cada ciclo de Evaluación del IPCC, se evalúan una multitud de escenarios, con diferentes alcances y énfasis a lo largo de los diversos Grupos de Trabajo e Informes Especiales y sus respectivos capítulos. Dentro de los informes, la ambición es integrar el conocimiento sobre posibles futuros climáticos en los Grupos de Trabajo y los dominios de investigación científica basados en un pequeño conjunto de "vías de encuadre", como las llamadas vías RCP del Quinto Informe de Evaluación del IPCC (AR5) y los escenarios SSP-RCP en el Sexto Informe de Evaluación (AR6). Esta perspectiva, iniciada por las discusiones en el taller del IPCC en Bangkok en abril de 2023 sobre el "Uso de escenarios en el IE6 y evaluaciones posteriores", pretende servir como una de las contribuciones de la comunidad para resaltar las necesidades de la próxima generación de vías de encuadre que se está avanzando bajo el paraguas del CMIP para su uso en el IE7 del IPCC. Aquí sugerimos una serie de objetivos de investigación de políticas que ese conjunto de vías de encuadre debería cumplir idealmente, incluidas las necesidades de mitigación para cumplir los objetivos del Acuerdo de París, los riesgos asociados con las estrategias de eliminación de carbono, las consecuencias del retraso en la promulgación de esa mitigación, la orientación para las necesidades de adaptación, las pérdidas y los daños, y para lograr la mitigación en el contexto más amplio de los objetivos de desarrollo social. Con base en este contexto, sugerimos que la próxima generación de escenarios climáticos para los Modelos del Sistema Terrestre evolucione hacia 'Vías de Emisión Representativas' (REP) y sugerimos categorías clave para tales vías. Estas "vías de encuadre" deberían abordar las políticas de mitigación y las necesidades de adaptación más críticas en los próximos 5–10 años. En nuestra opinión, las categorías más importantes son las relevantes en el contexto del objetivo a largo plazo del Acuerdo de París, específicamente una vía de acción inmediata (sobrepaso bajo) de 1,5 °C y una vía de acción retardada (sobrepaso alto) de 1,5 °C. Otras dos categorías clave son una categoría de vía aproximadamente en línea con los objetivos políticos actuales (expresados para 2023) a corto y largo plazo, y una categoría de emisiones más altas que está aproximadamente en línea con las "políticas actuales" (expresadas para 2023). También defendemos la relevancia científica y política de explorar dos "mundos que podrían haber sido". Una de estas categorías tiene trayectorias de altas emisiones muy por encima de lo que implican las políticas actuales, y la otra tiene trayectorias de muy bajas emisiones que asumen que la acción de mitigación global en línea con la limitación del calentamiento a 1.5 ° C sin sobrepasar había comenzado en 2015. Finalmente, observamos que el suministro oportuno de nueva información científica sobre las vías es fundamental para informar el desarrollo y la implementación de la política climática. Para el segundo Balance Global bajo el Acuerdo de París en 2028, y para informar el desarrollo posterior de las Contribuciones Determinadas a Nivel Nacional (NDC) hasta 2040, se requieren insumos científicos mucho antes de 2028. Estas necesidades deben considerarse cuidadosamente en el cronograma de desarrollo de las actividades de modelado comunitario, incluidas las del CMIP7. Abstract. In every IPCC Assessment cycle, a multitude of scenarios are assessed, with different scope and emphasis throughout the various Working Group and Special Reports and their respective chapters. Within the reports, the ambition is to integrate knowledge on possible climate futures across the Working Groups and scientific research domains based on a small set of ‘framing pathways’, such as the so-called RCP pathways from the Fifth IPCC Assessment report (AR5) and the SSP-RCP scenarios in the Sixth Assessment Report (AR6). This perspective, initiated by discussions at the IPCC Bangkok workshop in April 2023 on the “Use of Scenarios in AR6 and Subsequent Assessments”, is intended to serve as one of the community contributions to highlight needs for the next generation of framing pathways that is being advanced under the CMIP umbrella for use in the IPCC AR7. Here we suggest a number of policy research objectives that such a set of framing pathways should ideally fulfil, including mitigation needs for meeting the Paris Agreement objectives, the risks associated with carbon removal strategies, the consequences of delay in enacting that mitigation, guidance for adaptation needs, loss and damage, and for achieving mitigation in the wider context of Societal Development goals. Based on this context we suggest that the next generation of climate scenarios for Earth System Models should evolve towards ‘Representative Emission Pathways’ (REPs) and suggest key categories for such pathways. These ‘framing pathways’ should address the most critical mitigation policy and adaptation needs over the next 5–10 years. In our view the most important categories are those relevant in the context of the Paris Agreement long-term goal, specifically an immediate action (low overshoot) 1.5 °C pathway, and a delayed action (high overshoot) 1.5 °C pathway. Two other key categories are a pathway category approximately in line with current (as expressed by 2023) near- and long-term policy objectives, and a higher emissions category that is approximately in line with “current policies” (as expressed by 2023). We also argue for the scientific and policy relevance in exploring two ‘worlds that could have been’. One of these categories has high emission trajectories well above what is implied by current policies, and the other has very low emission trajectories that assume that global mitigation action in line with limiting warming to 1.5 °C without overshoot had begun in 2015. Finally, we note that timely provision of new scientific information on pathways is critical to inform the development and implementation of climate policy. For the second Global Stocktake under the Paris Agreement in 2028, and to inform subsequent development of Nationally Determined Contributions (NDCs) up to 2040, scientific inputs are required well before 2028. These needs should be carefully considered in the development timeline of community modelling activities including those under CMIP7. الملخص. في كل دورة تقييم للهيئة الحكومية الدولية المعنية بتغير المناخ، يتم تقييم العديد من السيناريوهات، مع نطاق وتركيز مختلفين في مختلف مجموعات العمل والتقارير الخاصة وفصولها. ضمن التقارير، يتمثل الطموح في دمج المعرفة حول المستقبل المناخي المحتمل عبر مجموعات العمل ومجالات البحث العلمي بناءً على مجموعة صغيرة من "مسارات التأطير"، مثل ما يسمى مسارات RCP من تقرير التقييم الخامس للهيئة الحكومية الدولية المعنية بتغير المناخ (AR5) وسيناريوهات SSP - RCP في تقرير التقييم السادس (AR6). يهدف هذا المنظور، الذي بدأته المناقشات في ورشة عمل الفريق الحكومي الدولي المعني بتغير المناخ في بانكوك في أبريل 2023 حول "استخدام السيناريوهات في التقرير التقييمي السادس والتقييمات اللاحقة"، إلى أن يكون أحد مساهمات المجتمع لتسليط الضوء على احتياجات الجيل القادم من مسارات التأطير التي يتم تطويرها تحت مظلة الفريق الحكومي الدولي المعني بتغير المناخ لاستخدامها في التقرير التقييمي السابع للفريق الحكومي الدولي المعني بتغير المناخ. نقترح هنا عددًا من أهداف أبحاث السياسات التي يجب أن تلبيها مجموعة مسارات التأطير هذه بشكل مثالي، بما في ذلك احتياجات التخفيف لتحقيق أهداف اتفاق باريس، والمخاطر المرتبطة باستراتيجيات إزالة الكربون، وعواقب التأخير في سن هذا التخفيف، وتوجيه احتياجات التكيف، والخسائر والأضرار، ولتحقيق التخفيف في السياق الأوسع لأهداف التنمية المجتمعية. بناءً على هذا السياق، نقترح أن يتطور الجيل التالي من سيناريوهات المناخ لنماذج النظام الأرضي نحو "مسارات الانبعاثات التمثيلية" (REPs) واقتراح الفئات الرئيسية لمثل هذه المسارات. يجب أن تتناول "مسارات التأطير" هذه أهم سياسات التخفيف واحتياجات التكيف على مدى السنوات الخمس إلى العشر القادمة. من وجهة نظرنا، فإن أهم الفئات هي تلك ذات الصلة في سياق الهدف طويل الأجل لاتفاق باريس، وتحديداً مسار الإجراء الفوري (التجاوز المنخفض) 1.5 درجة مئوية، ومسار الإجراء المتأخر (التجاوز العالي) 1.5 درجة مئوية. هناك فئتان رئيسيتان أخريان هما فئة المسار التي تتماشى تقريبًا مع أهداف السياسة الحالية (كما هو معبر عنه بحلول عام 2023) على المدى القريب والطويل، وفئة الانبعاثات الأعلى التي تتماشى تقريبًا مع "السياسات الحالية" (كما هو معبر عنه بحلول عام 2023). كما ندعو إلى الأهمية العلمية والسياسية لاستكشاف "عالمين كان من الممكن أن يكونا". واحدة من هذه الفئات لديها مسارات انبعاثات عالية أعلى بكثير مما تنطوي عليه السياسات الحالية، والأخرى لديها مسارات انبعاثات منخفضة للغاية تفترض أن إجراءات التخفيف العالمية بما يتماشى مع الحد من الاحترار إلى 1.5 درجة مئوية دون تجاوز قد بدأت في عام 2015. أخيرًا، نلاحظ أن توفير المعلومات العلمية الجديدة في الوقت المناسب حول المسارات أمر بالغ الأهمية لإثراء تطوير وتنفيذ سياسة المناخ. بالنسبة للتقييم العالمي الثاني بموجب اتفاقية باريس في عام 2028، وللإبلاغ عن التطوير اللاحق للمساهمات المحددة وطنيًا (NDCs) حتى عام 2040، هناك حاجة إلى مدخلات علمية قبل عام 2028 بوقت طويل. يجب النظر في هذه الاحتياجات بعناية في الجدول الزمني لتطوير أنشطة النمذجة المجتمعية بما في ذلك تلك الموجودة في إطار CMIP7.

The focus of the SITHOS project has been to develop and test new observing systems for sea ice thickness and related parameters for climate change detection, support to sea transport, offshore operations as well as environmental monitoring in polar regions. The project has collected and analysed new data sea ice sets from several field experiments, analyzed satellite altimeter data and conducted model simulations of sea ice in the Arctic. Sea-ice thickness is one of the most difficult ice parameters to measure, because it requires use of platforms which can operate in the ice environment The main achievements in SITHOS have been the field experiments where several methods of observing ice thickness have been successfully used to collect observations of ice thickness and related parameters. These methods have clearly complementary roles and should be used regularly in future observing systems. The main problem of most observing systems is that they cover local and regional scale, while for climate studies it is necessary to obtain data for the whole Arctic. Satellites has the capability to observe thickness on large scale and should be implemented as part of a global observing system with support from aircraft and in situ measurements. NERSC Technical Report no. Funded by EU, Contract no. EVK2-CT-2002-00146