Session themes

Session 1: How big is the open ocean carbon sink?

Conveners: Richard Sanders (ICOS OTC and NORCE), Siv Kari Lauvset (NORCE), Gregor Rehder (Leibniz-Institute for Baltic Sea Research), Carolina Cantoni (CNR-ISMAR)

The ocean plays a key role in the global climate system, taking up approximately 25% of the CO2 emitted to the atmosphere. However there exists a significant, highly publicized and poorly understood mismatch between model-derived and data product driven estimates of the ocean C sink within the Global Carbon Budget, which leads to uncertainty in the future trajectory of climate change. 

Multiple groups are working urgently to address this issue using a variety of approaches including: - assessing the impact of sampling bias and density within the existing sampling surface observing network,  - trying to accommodate uncertainties from differences in ocean surface and bulk mixed layer temperatures (i.e. surface skin effects) - re-addressing the role of the Southern Ocean, a region notoriously undersampled which is believed to be key in driving ocean carbon uptake,  - calculating ocean interior CO2 accumulation using data obtained from GO-SHIP,  - systematically evaluating model representations of the ocean sink and  - evaluating the impact of circulation changes.  In this session we will bring together these diverse perspectives, building on the results emerging from multiple projects to address this key issue in the global carbon cycle and provide fresh perspectives on important next steps.

Session 2: Marine Carbon Dioxide Removal - What have we learned and what are the emerging challenges for MRV confidence

Conveners: Pedro M. S. Monteiro, Stellenbosch University and David Ho, University of Hawaii

Here we focus on ocean CO2 observations, reconstructions and modelling science that underpin ocean CDR under positive (pre-2050) and negative emissions (post 2050). Although ocean observations are likely not to play a direct role on MRV because the mCDR CO2 signal weakens exponential from the intervention sites, they are critical to provide confidence on the models (variability and trends), the core of mCDR MRV. mCDR science has grown rapidly globally over the past 5 years through country-based and EU funded research projects, industry and philanthropy funded sea trials. This proposed session aims to provide a platform to synthesize and critically reflect on what has been learned on the feasibility, scalability and effectiveness of mCDR., and examine how ICOS, global observations and reconstructions can strengthen mCDR MRV.

We encourage presentations that offer syntheses of multiple sea trials (both observational and modelling) - highlighting what are we learning across multiple collaborative experiments - as well as individual sea trials carried out in diverse European seas, from the Baltic to the Mediterranean.

Session 3: Blue carbon and seaweed: reforestation and cultivation

Conveners: Luiza Neves (SINTEF Ocean), Annette Bruhn (Aarhus University), Nichole Price (Bigelow Laboratory for Ocean Sciences)

Macroalgae ecosystems are highly productive and play a key role in the marine carbon cycle, yet significant uncertainties remain in quantifying their net contribution to durable Carbon Dioxide Removal (CDR). Kelp forests are significant contributors to blue carbon sinks via the export of particulate and dissolved organic carbon. Similarly, reforestation and cultivation practices increase POC and DOC production and export from an area through renewable biomass growth, continuous DOC release and exudation and erosion of small particles or larger fragments. The fate of this POC, as well as the composition and biochemical processes involved in the transformation of POC and DOC into recalcitrant carbon have many data gaps. This session addresses the full spectrum of seaweed-based blue carbon strategies, from conservation to active cultivation; ecology to seawater chemistry, biogeochemistry, quantification methods and CDR products. We invite contributions on the "reforestation" and restoration of natural seaweed forests, focusing on methods to quantify their baseline carbon sequestration, ecosystem-scale CO2 flux, and associated co-benefits. Furthermore, this session will explore the rapidly emerging field of seaweed cultivation for CDR. This includes assessing the biogeochemical impacts of large-scale farming, the fate and permanence of sequestered carbon, and the critical development of robust Monitoring, Reporting, and Verification (MRV) frameworks.

Session 4: Carbon cycling in the land ocean aquatic continuum

Conveners: Richard Sanders (ICOS Ocean Thematic Centre and Norwegian Research Centre), Abdirahman M. Omar (Norwegian Research Centre), Karol Kulinski (Institute of Oceanology of the Polish Academy of Sciences), Carolina Cantoni (Institute of Marine Sciences, CNR-ISMAR), Yoanna Voynova (Helmholtz-Zentrum Hereon), Janne-Markus Rintala (ICOS ERIC)

The land-ocean aquatic continuum, comprising rivers, marshes, swamps, estuaries, bogs and coastal shelf seas, is a key region for carbon cycling. Terrestrial and river-borne organic matter enters from rivers, some is respired and lost to the atmosphere, some is buried in sediments, and some is transferred through to the open ocean, with the climate effect of these partitions being dependent on their fate. Despite their importance, we lack crucial information around these fluxes, including their persistence over time, the controls over these fluxes and their losses. Climate change is likely to modify these considerably, and human influence is large due to so-called Blue Carbon activities. This session will discuss the emerging paradigms in the field and welcome technological, modelling and in situ studies from diverse regions around the world, including high organic C landscapes in peatland regions such as Fennoscandia, Canada and SE Asia. A key focus will also be on shifts in carbonate system chemistry in coastal waters, driven by changes in total alkalinity related to freshwater inputs which. By integrating studies on both organic and inorganic carbon, we aim to comprehensively advance our understanding of the critical role of the land-ocean aquatic continuum in the global carbon cycle.

Session 5: Advancing marine CO₂ observations through next-generation sensors, integration and platform innovation

Conveners: Laurent COPPOLA, (Sorbonne University), Socratis Loucaides (NOC), Edouard Leymarie (LOV/CNRS), Ute Schuster (Univ. Exeter), Simo Cusi (EMSO ERIC), Romain Cancouet (EURO-ARGO ERIC), Richard Sanders (NORCE and OTC-ICOS), Janne-Markus Rintala (ICOS ERIC)

Accurate in-situ quantification of oceanic CO₂ fluxes is crucial for the determination of global CO2 fluxes with high confidence, due to spatial and temporal variability that numerical models cannot always identify. Yet this remains a major challenge for carbon cycle research. Progress now depends on the development and convergence of innovative technologies (sensors, samplers) that can deliver long-term, high-quality measurements across diverse ocean environments. This session will bring together projects, research infrastructures and institutes working to improve marine CO₂ observing technologies, from novel autonomous sensors to integrated observing platforms such as gliders, floats, buoys, moorings and surface vehicles. Discussions will address sensor calibration and validation, data interoperability, and the integration of these technologies into operational networks such as European Infrastructures (ICOS, EMSO, Euro-Argo) and international networks (SOCONET). Initiated by the Horizon Europe project GEORGE, which co-develops and demonstrates next-generation sensors and integrated platforms across European Research Infrastructures, this session also welcomes contributions from related initiatives — including those exploring new observational data analysis and quality control methods and tools including Artificial Intelligence. By fostering exchanges across disciplines and communities, the session aims to define a shared technological vision for the future European and global marine carbon observing system.

Session 6: Carbon cycle in the Mediterranean region: from the local to the regional scale

Conveners: Paolo Cristofanelli (CNR-ISAC), Carolina Cantoni (CNR-ISMAR), Gabriele Guidolotti (CNR-IRET)

The Mediterranean region is recognized as a global “hot-spot” in terms of the impacts of climate change and anthropogenic pressure on the environment. It is characterized by highly heterogeneous landscapes, distinctive oceanographic features, biodiverse ecosystems and densely populated regions which make it difficult to consistently upscale local processes. By contributing to a better understanding of processes which affect the carbon cycle and the carbon budget in the Mediterranean region, this session stimulates knowledge exchange within the international scientific communities interested in the Carbon cycle in this complex key-region.

It welcomes contributions from different approaches (ground/sea-based and satellite observations, models) and different domains (atmosphere, ecosystems, oceans) to provide insights into carbon fluxes, including the impact of extreme events (e.g., wildfires, heatwaves, droughts, floods), climate variability and anthropogenic activities on the regional carbon fluxes and budget. Contributions can cover different spatial (from local to regional) and temporal (from decades to daily, from the past to the future) scales. Cross-domain, cross-techniques and upscaling/downscaling studies are very welcome together with contributions discussing the most relevant knowledge gaps and future directions.

Session 7: CO2 and CH4 cycle dynamics in Africa: observations, processes, and climate implications

Conveners: Elsa Ordway (Institute of the Environment and Sustainability at UCLA), Michel Ramonet (CNRS), Wahid Mellouki (CNRS)

Africa plays a decisive role in global carbon cycles, with vast and diverse ecosystems (tropical forests, savannas, wetlands, agricultural systems) that strongly influence CO₂ and CH₄ fluxes. Yet the continent remains underrepresented in observation networks, leading to significant uncertainties in regional and global budgets. This session aims to bring together the scientific community working on greenhouse gases in Africa to highlight recent advances, critical gaps, and prospects for enhanced monitoring in this key region for the climate.

The session will welcome contributions on:

• in situ and satellite observations of CO2 and CH4 concentrations in Africa
• modeling of biogeochemical processes in African ecosystems
• methane emissions from wetlands, rice paddies, livestock farming, and energy systems
• the impacts of droughts, vegetation fires, and land use changes
• integration of African data into atmospheric inversions and global budgets
• implications for climate policies, national inventories, and mitigation strategies

Session 8: Methane in situ measurements in Latin America and the Caribbean

Conveners: Marcos Andrade (Universidad Mayor de San Adrés), Nicolas Huneeus (Universidad de Chile), Florencio Utreras (Copernicus LAC-Chile and University of Chile)

Methane (CH₄) is a key climate forcer in Latin America and the Caribbean, where diverse and often variable sources challenge robust quantification and attribution. The region includes extensive tropical wetlands (e.g., the Amazon basin, Llanos de Moxos), a rapidly expanding livestock sector, and significant emissions from waste management, sanitary landfills, and oil/gas operations. Strengthening the evidence base for CH₄ in South American settings is therefore essential for both regional and global mitigation efforts.

The session is open to research on long-term monitoring (in situ, remote sensing) and recent intensive field campaigns to reduce persistent uncertainties regarding regional CH₄ emissions. The session proposes to explore how observations are exploited through inverse modeling to better constrain national and regional budgets, particularly when combined with satellite observations (e.g., GOSAT, SENTINEL-5p). The session is also open to high-resolution studies conducted from aircraft and on the ground throughout the region, including campaigns on Bolivian seasonal wetlands, characterization of emissions from major landfills (e.g., in Brazil), and targeted surveys of oil/gas and agricultural sources. By bringing together data recorded by fixed stations and data from intensive campaigns, the session aims to provide an essential platform for scientific exchange and policy-relevant discussions.

Session 9: Carbon processes in high latitude/high altitude ecosystems under climate change

Conveners: Junbin Zhao (Norwegian Institute of Bioeconomy Research), Holger Lange (Norwegian Institute of Bioeconomy Research) Didier Voisin (Université Grenoble Alpes)

High latitude/high altitude ecosystems store immense amounts of carbon that is central to global climate regulation. These systems face rapid, compounding threats that could flip them from carbon sinks to sources.

This session invites research on the vulnerability and resilience of high latitude / high altitude carbon processes under a complex setting of changes. We seek contributions that address the following areas for these ecosystems:

1. Winter Climate Change: How altered winter processes (e.g., snow cover, freeze-thaw cycles, and respiration) are shifting the annual carbon balance and nutriment fluxes.
2. Ecosystem Responses to Environmental Change: Quantifying how shifts in ecosystem structure and function (e.g., vegetation dynamics, soil processes) affect carbon fluxes and storage under changing conditions.
3. Pathways for Climate Adaptation and Carbon Stability: Exploring strategies and natural processes that enhance ecosystem resilience and maintain carbon stocks in the face of climate change.

We welcome submissions utilizing ICOS data, remote sensing, modeling, or field experiments to quantify changes in carbon and other key greenhouse gas (e.g., CH4, N2O) fluxes in these ecosystems. The goal is to inform monitoring, modeling, and sustainable management in this globally critical and rapidly changing region.

Session 10: Cross-scale responses of greenhouse gas variability to climate extremes

Conveners: Wenxin Zhang (University of Glasgow and Lund University), Patrik Vestin (Lund University), Mousong Wu (Nanjing University)

Climate extremes, such as temperature extremes, heavy precipitation, floods, storms, and compound events, are becoming more frequent and intense under ongoing climate change. These events impose strong and often nonlinear impacts on greenhouse gas (GHG) fluxes (CO₂, CH₄, and N₂O), altering carbon and nitrogen cycling from daily pulses to decadal shifts. Despite increasing evidence, our mechanistic understanding of how ecosystems respond to extremes remains limited, creating substantial uncertainties in predicting biosphere–atmosphere feedbacks.

This session invites contributions that explore GHG variability during and after extreme events across a wide range of ecosystems, including tundra, forests, wetlands, grasslands, croplands, and aquatic environments. We particularly welcome studies employing diverse approaches such as in situ measurements (eddy covariance, chambers, isotopes), experimental manipulations, process-based and Earth system models, and satellite or airborne remote sensing datasets. Integrative research that combines observations and models to disentangle drivers, quantify legacy effects, and upscale local processes to regional or global scales is especially encouraged.

By bringing together observational, experimental, and modelling perspectives, this session aims to identify emerging patterns in GHG responses to extremes, highlight methodological advances across scales, and define critical knowledge gaps. Our goal is to foster cross-disciplinary collaborations and improve future predictions of GHG exchange.

Session 11: Climate feedbacks from ecosystem management and natural disturbances

Conveners: Mana Gharun (University of Münster), Natascha Kljun (Lund University), Anne Klosterhalfen (University of Göttingen), Mathias Herbst (German Weather Service – DWD)  

Ecosystem management decisions — through agricultural and forestry practices, conservation, or restoration — along with natural disturbances such as wildfires, windthrow, pathogen outbreak, strongly influence the physical, chemical, and biological functioning of ecosystems. These processes alter key carbon, nitrogen, water, and energy fluxes, thereby modifying greenhouse gas exchange and feedback between ecosystems and the climate system.
This session welcomes contributions that use field observations, experimental data, modelling, or remote sensing at various scales to quantify the effects of management practices (for example ecosystem restoration) and/or natural disturbances on ecosystem–atmosphere exchanges of energy and matter. We particularly encourage studies that integrate carbon, nitrogen, water, and energy fluxes to elucidate how management and disturbance shape the climate feedbacks of terrestrial and aquatic ecosystems.

Session 12: Comparing long-term eddy covariance measurements in terrestrial ecosystems with carbon stock variations: lessons and future challenges

Conveners: Jean-Marc Limousin (CNRS), Katja Klumpp (INRAE), Bernard Heinesch (University of Liege), Rachael Murphy (TEAGASC)

The carbon sink of terrestrial ecosystems is either stored in soils and biomass or exported after harvest. Measuring carbon stock evolution through time along with crop or wood production, thus remains the reference method for quantifying the carbon budgets of ecosystems. Over recent decades, eddy covariance measurements have given us new mechanistic insights into the short to medium term response of photosynthesis and respiration to seasonal climate variations, management practices, and disturbances. However, until recently, eddy covariance time series were generally too short to allow robust comparisons with carbon budget estimates based on carbon stock variations. Today, many eddy covariance sites spanning at least a decade of continuous measurements, together with a consolidated methodology for measuring, calculating and gap-filling fluxes, open the possibility to compare the two methods and learn more about carbon sequestration and residence time in ecosystems. ICOS ecosystem sites are also well suited to modeling soil organic carbon evolution through time thanks to detailed ancillary data on soil and ecosystem management. This session welcomes contributions addressing scientific questions based on the quantitative comparison of carbon fluxes versus carbon stock variations or proposing methodological solutions to explain and resolve potential discrepancies between them.

Session 13: Advancing approaches for quantifying greenhouse gas fluxes in terrestrial ecosystems

Conveners: Manuel Acosta (Global Change Research Institute, Czech Academy of Sciences), Natalia Kowalska (Global Change Research Institute, CAS), Pedro Coimbra (Écologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), INRAE, AGROPARISTECH), Rachael Murphy  (Teagasc)

Quantifying greenhouse gas (GHG) fluxes at multiple spatial and temporal scales is fundamental to understanding terrestrial contributions to the global carbon budget. This section focuses on advancing observational and analytical approaches for assessing carbon and GHG dynamics on terrestrial systems (forest, peatland and wetland), emphasising the integration of in situ measurements and process-based modelling.

A particular focus will be on the effects of land use, land-use change, and ecosystem management on GHG fluxes. Contributions addressing methodological developments in measurements, modelling and/or uncertainty assessments of GHG fluxes, partitioning of ecosystem components and the scaling of site-level data to regional/national carbon budgets are especially encouraged.

The session aims to foster discussion on harmonised data frameworks, uncertainty analysis, and cross-comparison of observational and modelling approaches. By bringing together researchers from diverse disciplines, it seeks to strengthen the empirical and conceptual basis for understanding the role of terrestrial ecosystems in climate mitigation and for improving the robustness of carbon budget assessments.

Session 14: Greenhouse gas fluxes in agroecosystems: processes, measurements and management implications

Conveners: Iris Feigenwinter (ETH Zurich), Patrik Vestin (Lund University), Rachel Murphy (Teasgasc), Tobias Biermann (Lund University), Torbern Tagesson (Lund University), Mari Pihlatie (University of Helsinki), Lutz Merbold (Agroscope), Christof Ammann (Agroscope), Angelika Kübert (University of Helsinki)

Agriculture is a major source of greenhouse gases (GHGs) such as nitrous oxide (N₂O) and methane (CH₄) but also offers opportunities for climate change mitigation through net carbon uptake by the agroecosystem and sustainable land use. Understanding the environmental and management drivers of the GHG exchange is critical for improving GHG budgets and developing effective mitigation strategies.

This session aims to advance knowledge on GHG (CO2, N2O, CH4) fluxes in agricultural ecosystems (e.g. grasslands, croplands) and explore pathways toward sustainable and resilient agriculture. We welcome contributions that:

• Quantify GHG budgets using field observations and experiments (by eddy covariance and chamber methods), or remote sensing.
• Investigate environmental and management effects (e.g., soil moisture, temperature, fertilization, harvest, tillage) on N₂O and CH₄ fluxes.
• Focus on biogeochemical processes related to GHG production/consumption (e.g. via stable isotopes).
• Apply modelling frameworks to assess climate impacts and mitigation scenarios.
• Integrate multi-scale data for regional and global assessments.
• Explore innovative cropping systems and land-use strategies, including stress-tolerant crops.

We welcome studies across different spatial and temporal scales, as well as studies using interdisciplinary approaches.

Session 15: Peatlands in the global climate system: fluxes, feedbacks, and human pressures

Conveners: Merit van den Berg (UK Center of Ecology & Hydrology), Brenda D’Acunha (UK Centre of Ecology & Hydrology), Alexander Cumming (UK Centre of Ecology & Hydrology), Bart Kruijt (Wageningen University & Research), Janne Rinne (Natural Resources Institute Finland (Luke)), Xuefei Li (University of Helsinki), Claire Treat (Aarhus University), Paul Mathijssen (Wageningen University and Research)

Peatlands store more carbon globally than the live biomass of all forests and play a critical role in regulating biogeochemical, water, and energy cycles. Depending on their degree of disturbance, they can act as sources or sinks of carbon dioxide (CO2) and methane (CH4), functioning as both cooling and warming components of the climate system. Understanding the fluxes of greenhouse gases, water, and energy in peatlands, and the drivers that control them, is essential for accurately predicting peatland responses to environmental change and anthropogenic disturbances such as drainage for agriculture, forestry, peat extraction, and conversion to other land uses.

This session invites studies that explore peatland dynamics and processes across diverse peatland types, management regimes and climate zones. We welcome research on atmospheric fluxes of CO₂, CH₄, N₂O, water, energy, and the interactions among them. Submissions using a wide range of approaches are encouraged, including eddy covariance, chamber measurements, remote sensing, paleoclimatology, biogeochemical process studies, and modelling. Studies that integrate multiple spatial or temporal scales to connect site-level observations with regional or global assessments are particularly welcome. We also invite contributions that reflect on needs and opportunities for peatland monitoring programs, including initiatives such as ICOS.

Session 16: Using sun-induced chlorophyll fluorescence to understand or scale EC fluxes

Submitted by Simon De Canniere (University of Antwerp), Luis Alonso (Mediterranean Center of Environmental Studies CEAM)

Sun-Induced Chlorophyll fluorescence (SIF) is an electromagnetic signal linked to the activity of the photosystems, which are driving the light reactions of photosynthesis. SIF can be measured at the scale of leaf, canopy, landscape or biome with in-situ, airborne or spaceborne sensors. Eddy Covariance (EC) is a complementary technique that measures CO2 exchange by an ecosystem, thereby calculating the net ecosystem exchange (NEE) at the scale of a landscape. Combining SIF and EC provides two opportunities. First, as SIF's sensitivity to photosynthesis is rooted in the light reactions, while EC is rooted in the Calvin cycle activity. A combination of these two measurements provides a more complete image on plot photosynthesis. Second, SIF can be retrieved at large spatial scales allowing us to improve our understanding of the global carbon cycle. In this session, we invite speakers to present their work on either of these subjects, as well as on adjacent subjects including sensor advancements, stress monitoring, photosynthesis modelling, etc.

Session 17: Urban greenhouse gas emissions and sinks: from advanced monitoring to source identification and impact

Conveners: Leena Järvi (University of Helsinki),: Andreas Christen (University of Freiburg), Stavros Stagakis (University of Basel)

Urban areas are among the largest contributors to global greenhouse gas (GHG) emissions. A detailed understanding of the total urban GHG balance, its components and their temporal and spatial variability is essential for designing effective emission reduction strategies. In addition to the anthropogenic emissions, the biogenic components of the urban GHG balance must be quantified to reduce uncertainties in emission estimations and to assess the potential role of urban vegetation for carbon sequestration. A wide range of complementary methods are being used to characterize urban GHG budgets and source attribution, including micrometeorological flux measurements, isotope analyses, inverse and forward modelling approaches, and high-resolution emission inventories. There are also emerging technologies, such as dense sensor networks, mobile measurements, and ground-based remote sensing. Furthermore, GHG monitoring networks can be complemented with observations of co-emitted species and aerosol particles.   

This session brings together studies advancing the quantification, monitoring, understanding, and interpretation of urban GHG fluxes and their controlling factors across scales. We welcome conceptual, experimental, observational, and modelling contributions addressing urban GHG source apportionment, associated uncertainties, and methodological innovations. Studies demonstrating how these approaches can support cities’ climate strategies and emission mitigation plans are also encouraged.

Session 18: Quantifying anthropogenic greenhouse gas emissions from continental to regional scales

Conveners: Samuel Hammer (ICOS CRL, IUP, Heidelberg University), Ingrid Luijkx (WUR), Gregoire Broquet (LSCE)

Accurate quantification of anthropogenic greenhouse gas (GHG) emissions across continental to regional scales is fundamental for tracking progress toward emission-reduction targets and for supporting monitoring, reporting, and verification (MRV) frameworks. This session focuses on advances in science-based methods for detecting, quantifying, and tracking fossil fuel and other anthropogenic GHG fluxes.

We encourage contributions that apply direct observational methods, inverse modelling techniques, or AI approaches that integrate statistical and observational data. Submissions combining these strategies are particularly welcome. Studies may explore the use of ICOS atmospheric observations together with satellite and other remote sensing observations, as well as bottom-up inventories, to quantify, constrain, and independently validate anthropogenic emission estimates.

Topics of interest include, but are not limited to: • Continental- to regional-scale anthropogenic GHG budgets and trends • Inverse modelling and hybrid data-assimilation frameworks • Integration of atmospheric, modelling, and inventory data for MRV applications • Cross-scale validation and intercomparison of anthropogenic emission estimates This session aims to highlight innovative, policy-relevant methods that enhance our capacity to monitor anthropogenic GHG emissions and build confidence in emission verification across Europe and beyond.

Session 19: Understanding feedbacks between greenhouse gas exchange processes and climate variability using in situ observations, remote sensing, and machine learning 

Conveners: Thomas Lauvaux (Laboratoire des Sciences du Climat et de l’Environnement), Mathias Göckede (Max Planck Institute for Biogeochemistry), Sanam Vardag (University of Heidelberg), Vitus Benson (Max Planck Institute for Biogeochemistry)

With the atmosphere serving as an integrator for surface-atmosphere exchange processes across scales, monitoring and interpretation of atmospheric greenhouse gas (GHG) signals provides fundamental information on carbon, energy and water fluxes from natural and anthropogenic sources. Combining observations with modeling frameworks in process-based studies can reveal key mechanisms and drivers governing carbon-climate feedback processes, generating vital information to predicting their future evolution in a changing climate. In addition, recent data-driven Machine Learning (ML) approaches have also become popular for studying different components of the carbon cycle. 

This session focuses on modeling frameworks (top-down and bottom-up) that investigate GHG exchange processes using observational platforms such as, localized surface networks (e.g. ICOS Atmosphere and Ecosystem, Fluxnet, NOAA,…), aircraft campaigns (e.g. MAGIC, COMET, ), or active and passive remote-sensing missions (e.g., ECOSTRESS, OCO-2/3, TROPOMI, GOSAT). This session particularly targets works that integrate diverse data sources that are not traditionally combined. We particularly target studies exploring how the fusion of diverse observations with modeling frameworks using machine learning and novel data assimilation approaches can reveal key mechanisms governing carbon-climate feedback processes, advancing our understanding of their evolution in a changing climate.

Session 20: Unmanned autonomous vehicles and proximal sensing in greenhouse gas research and monitoring 

Conveners: Benjamin Brede (GFZ Helmholtz Centre for Geosciences), Enrico Tomelleri (Free University of Bozen-Bolzano), Bert Gielen (University of Antwerp), Jean-Daniel Paris (Laboratoire des Sciences du Climat et de l’Environnement LSCE), Thanos Gkritzalis (Vlaams Instituut voor de Zee VLIZ)

For terrestrial ecosystems, proximal sensing technologies such as ground-based optical sensor networks, repeat lidar scanning, UAV-mounted multispectral or lidar systems are transforming our ability to monitor processes at fine spatial and temporal scales. These approaches can bridge the gap between in-situ and satellite measurements, providing insights into ecosystem function, and carbon dynamics. In atmospheric and marine environments the adaptation of new GHG analyzers on drones and USVs, provide the opportunity to augment and optimize the observation networks on both temporal and spatial terms. Such approaches can enhance the interpretation of GHG flux measurements, support model–data integration and enable upscaling to landscape and regional levels.  

This session invites contributions that explore novel proximal sensing technologies, methods for data integration and case studies demonstrating their application in GHG monitoring and ecosystem characterization. We welcome studies linking proximal sensing observations with ICOS ecosystem, atmospheric, and oceanic data, as well as initiatives contributing to calibration and validation frameworks for Earth Observation (EO) products. This session aims to showcase the above and foster dialogue between researchers, technologists, and stakeholders, and to highlight how proximal sensing can strengthen ICOS and similar infrastructures in addressing current and future challenges in greenhouse gas research.

Session 21: Emerging approaches for greenhouse gas flux measurements

Conveners: Claire Treat (Aarhus University), Felix Vogel (Environment and Climate Change Canada), David Bastviken (Linköping University)

Quantifying greenhouse gas emissions can be challenging due to strong spatial and temporal heterogeneity in sources, particularly for methane emissions. Advances in instrumentation and low-cost sensor technologies are allowing new types and approaches for measurements to capture these heterogeneous sources. In this session, we welcome contributions using new techniques, such as mobile or UAV-based GHG measurement platforms. We also welcome contributions related to the use of low-cost sensors, including calibration, verification, and measurement strategies, as well as other emerging GHG flux measurement approaches.

Session 22: Remote sensing and flux observations to link disturbance, ecosystem states, and carbon-water fluxes

Conveners: Simon Besnard (GFZ Helmholtz Centre for Geosciences), Torbern Tagesson (Lund University), Alba Viana Soto (Technical University of Munich), Arianna Lucarni (University of Sassari), Jacob Nelson (Max Planck Institute for Biogeochemistry), Marta Galvagno (Environmental Protection Agency of Aosta Valley), Martin Jung (Max Planck Institute for Biogeochemistry), Sophia Walther (Max Planck Institute for Biogeochemistry), Lanhuie Wang (Lund University), Hakim Abdi (Lund University)

Recent advances in space- and airborne sensors, such as hyperspectral missions (EnMAP), LiDAR (GEDI, ICESat-2), airborne laser scanning (ALS), radar systems (Sentinel-1, NISAR), microwave observations, land-surface temperature (LST), and solar-induced chlorophyll fluorescence (SIF), combined with ICOS/FLUXNET eddy-covariance networks, offer unprecedented capacity to observe ecosystem structure, disturbance, and function. Together, these data streams enable a new generation of models linking ecosystem state to carbon-water-energy exchanges and their responses to land use, management, and extreme events. They also open the door to more rigorous monitoring, reporting, and verification (MRV) frameworks, where ICOS station data play a central role in constraining and validating remote-sensing-derived estimates.

Aligned with the ICOS 2026 theme “Science, Data, Services: Together for Climate Action”, this session invites contributions that:

• Combine site-level flux and disturbance data with hyperspectral, LiDAR, ALS, and SAR observations;
• Quantify the effects of disturbance and management on flux variability, ecosystem resilience, and footprint representativeness;
• Detect and attribute ecosystem responses to droughts, heatwaves, storms, fires, and other extreme events;
• Develop frameworks to predict NEE, GPP, and evapotranspiration from integrated in-situ and satellite data;
• Evaluate and verify nature-based climate solutions through robust MRV frameworks, including approaches that leverage ICOS in-situ measurements.

We welcome studies involving calibration and validation using ICOS/FLUXNET sites, joint analyses with ESA/Copernicus missions, and the use of ICOS elaborated and near-real-time products. By bridging flux networks, airborne campaigns, and satellite missions, the session aims to pave the way for next-generation, footprint-aware upscaling of ecosystem carbon and water fluxes. A particular focus will be on capturing how disturbances and ecosystem-state dynamics shape flux variability and long-term resilience across space and time, while highlighting the role of integrated EO-ICOS approaches in strengthening MRV efforts and continental-scale monitoring of terrestrial carbon-water interactions.

Session 23: Remote sensing and vertical profiling of atmospheric greenhouse gases for climate action

Conveners: Mahesh Kumar Sha (Royal Belgian Institute for Space Aeronomy BIRA-IASB), Sindu Raj Parampil (ICOS ERIC) and Rigel Kivi (Finnish Meteorological Institute FMI)

Greenhouse gas (GHG) monitoring is carried out using in-situ and remote sensing techniques. While in-situ monitoring is performed by sampling the air either at the Earth’s surface or using airborne platforms to obtain profile information, remote sensing techniques provide complementary information on the total and/or partial columns of the atmosphere. Ground- and satellite-based instruments can retrieve column concentrations of GHGs from the Earth’s surface to the top of the atmosphere. The ground-based remote sensing networks TCCON, NDACC-IRWG and COCCON provide Fiducial Reference Measurements of GHGs used for satellite and model validation studies. Satellites are also continuously improving, both in terms of their observational capabilities and in reducing the uncertainties of the derived products: starting from global GHG Mappers like SCIAMACHY (2002), Sentinel-5 Precursor (2017), MicroCarb, Sentinel-5 (2025) and upcoming missions such as CO2M, MERLIN. Since 2016, there are also small satellites called Facility Scale Plume Monitors contributing to the quantification of GHG emissions from space.

We invite submissions on new atmospheric remote sensing and vertical profiling techniques or sensors, innovative measurement methods and scientific applications; and validation techniques for satellite and model data evaluation that are critical for building up monitoring and verification support (MVS) capacity and climate action.

Session 24: Exchange of reactive gases and aerosols between the land surface and the atmosphere in natural and managed ecosystems

Conveners: Silvano Fares (National research council of Italy), Giacomo Gerosa (Università Cattolica di Brescia), Christian Brümmer (Thünen Institute of Climate-Smart Agriculture) 

The land surface-atmosphere exchange of reactive trace gases and aerosols plays a major role  in atmospheric chemistry and its quantification is important for air quality assessment. The  ICOS network offers the opportunity to complement common observations of greenhouse  gases with flux measurements of reactive compounds such as nitrogen oxides (NOx), ozone, ammonia, volatile organic compounds (VOCs), and particles between plant ecosystems and  the atmosphere. While some of these compounds are anthropogenically produced, many are  biotic in origin and are emitted in-situ or produced from rapid photochemistry in the canopy.  The plant canopy represents a dynamic and rapidly changing environment in which a myriad  of biological, chemical and physical processes take place over very short time scales.  Advanced techniques of flux measurements provide in-depth knowledge of net fluxes of these  compounds above canopies, while additional in-canopy measurements enable a more detailed  understanding of individual processes and reactions driving these fluxes. Advanced measurement techniques can support the parametrization of models for a mechanistic  understanding of in-canopy dynamics of deposition and emission of these reactive gases. We encourage submission of contributions based on in-situ measurements  and/or modeling that improve our understanding of biosphere-atmosphere exchange of  reactive gases and aerosols and in-canopy processes.

Session 25: Exploring interconnected air quality and climate challenges in urban scale with harmonized research infrastructure data and tools

Conveners: Tuukka Petäjä, (INAR/University of Helsinki), Michel Ramonet (CNRS), Xavier Querol (CSIC, IDAEA)

Understanding the interactions between air quality and climate is essential for addressing the environmental global challenges. This session invites contributions that advance integrated observational approaches, with a focus on the complementary strengths of the ICOS and ACTRIS research infrastructures. Both infrastructures provide high-quality, standardized data streams that enable scientists to link greenhouse gas fluxes, atmospheric composition, and trace gases and aerosol properties across spatial and temporal scales.

Recent EU projects such as RI-URBANS and ICOS Cities highlight the critical role of both air quality and climate observations in supporting urban policy, improving emissions inventories, and delivering actionable information for stakeholders. This session encourages submissions that explore novel measurement strategies, cross-infrastructure synergies, harmonization of methodologies, and case studies demonstrating the value of coordinated data for understanding sources, sinks, and atmospheric processes.

We particularly welcome abstracts addressing urban and regional applications in air quality and climate challenges, long-term monitoring, integration of in situ and remote sensing data, and approaches that bridge scientific research with decision-making. By bringing together experts from both communities, the session aims to foster collaboration, highlight emerging results, and strengthen the scientific foundation for future environmental services. Researchers at all career stages are encouraged to submit abstracts.

Session 26: Designing the ideal global greenhouse gas monitoring network

Conveners: Alex Vermeulen (ICOS ERIC and Lund University), Prabir Patra (JAMSTEC), Oksana Tarasova (WMO)

A global effort is needed to transfer from the current Greenhouse Gas observation network on a voluntary basis in scientific mode to an operational network based on a secure governance model. The Global Greenhouse Gas Watch (G3W) initiative aims at setting up such a network. This requires a common set of monitoring approaches and principles applied across observing networks aiming at integration in WMO. The GHG community should define whether and how a tiered network structure can be adopted. The cost-efficient design of the observing network is needed for the implementation at WMO member countries and international community, utilizing common monitoring principles across domains. Strategies for the development of the satellite segment of the GHG observing system are well established but the surface (including over the ocean) network design needs further optimization. 

In this session we invite contributions from for example the modelling (e.g. TRANSCOM) and observation community for all domains on the following topics: • Network optimization based on the results of model intercomparisons • Network optimization based on footprint analysis • Results of the Observing System Simulation Experiments, including benefits and impact of the optimized networks

Session 27: The potential of Research Infrastructures for MRV development 

Conveners: Thomas Dirnböck (Environment Agency Austria), Liisa Kulmala (Finnish Meteorological Institute), Eric Ceschia (INRAE), Istem Fer Polat (Finnish Meteorological Institute), Tiphaine Tallec (University of Toulouse), Layla Höckerstedt (Finnish Meteorological Institute), Ville Kasurinen (ICOS ERIC), Hannes Mollenhauer (Helmholtz Centre for Environmental Research UFZ), Ulf Mallast (Helmholtz Centre for Environmental Research UFZ)

Monitoring, Reporting and Verification (MRV) is essential to ensure the credibility of national greenhouse gas (GHG) inventories, emission trading systems, and emerging carbon removal certification schemes. Research Infrastructures (RIs) such as ICOS and eLTER, are well positioned to co-develop services that directly support monitoring, reporting and verification (MRV) of carbon fluxes, carbon stocks, and land-based carbon removals. Yet, the systematic use of atmospheric and ecosystem GHG observations for these purposes remains limited. These services can draw on multi-decadal data on greenhouse gas exchange, soil carbon dynamics, and land-use change, while revealing co-benefits and trade-offs such as biodiversity, water regulation, and ecosystem resilience. Building on their complementary strengths, RIs can help bridge observational science, modelling, and applied climate services, ensuring robustness, interoperability, and policy relevance over the long term. 

We invite contributions that demonstrate how measurement-based approaches, flux station data, and data-driven modelling can complement, support, and independently verify MRV development. Topics may include model-data integration, machine learning approaches, error propagation, uncertainty quantification, cost-accuracy and policy-relevant applications. Interdisciplinary submissions that illustrate opportunities for next-generation RI-based MRV services from scientific, technical, and policy perspectives are strongly encouraged.

Session 28: Combining data and models to support emissions estimation and policy at local to regional scales

Conveners: Rona Thompson (NILU), Thomas Röckmann (University of Utrecht), Marko Scholze (Lund University)

Atmospheric observations of greenhouse gases, and related tracers, provide a wealth of information on their sources and sinks. This information can be harnessed using models of atmospheric transport to gain insights into the spatial and temporal distribution of greenhouse gas emissions and removals. This session focuses on employing models, and especially atmospheric inversions, to improve estimation of greenhouse gas emissions and removals, at national and regional scales. Particular attention will be paid to studies using atmospheric observations to verify and improve national greenhouse gas inventories or to support the monitoring of emission mitigation policies.

Session 29: Using GHG measurement data to support national greenhouse gas inventories

Conveners: Annalea Lohila (Finnish Meteorological Institute and University of Helsinki (INAR)), Andreas Ibrom (Technical Univ. of Denmark), Juha Mikola (Natural Resources Institute Finland), Janne Rinne (Natural Resources Institute Finland), Ivan Mammarella (University of Helsinki (INAR)), Tuula Aalto (Finnish Meteorological Institute), Hermanni Aaltonen (Finnish Meteorological Institute)

Monitoring, verification and reporting is a new tool to establish the credibility of the upcoming emission trading system. With this respect, direct greenhouse gas (GHG) measurements from ICOS and other observation networks provide a unique opportunity to verify the accuracy of national GHG inventories and improve methodologies. Currently, the use of atmospheric and ecosystem GHG observations for these purposes is still limited. This session invites contributions that explore how measurement-based approaches and data-driven modelling, including atmospheric inversions, urban-, landscape- and ecosystem-scale flux data, and integrated modelling frameworks, can complement, support, and independently verify inventory development. We welcome case studies, methodological advances, and collaborative projects that link measurement data (such as ICOS data, but not limited to) with national inventory systems. The aim is to foster dialogue among researchers, inventory communities and intergovernmental organizations, identify best practices, and discuss the challenges and opportunities of integrating direct GHG measurements into operational inventory work.

Session 30: Assessing impact in RIs

Conveners: Evi-Carita Riikonen (ICOS ERIC), Sindu Raj Parampil (ICOS ERIC)

In this session, we explore a vital part of the environmental research Infrastructures (ENVRIs) life cycle: understanding and assessing socio-economic impact. Demonstrating impact is crucial — not only to justify public investment, but also to show how ENVRIs contribute to science, innovation, policy, and societal well-being.

There is no single method for assessing impact. Each ENVRI’s mission, governance, and stakeholder context shape how it defines, measures, and communicates impact. For some, impact is immediate and measurable; for others – especially for ENVRIS - it evolves over time through knowledge transfer, capacity building, or policy influence.

Impact is often framed as socio-economic, yet emphasis differs across ENVRIs. Accordingly, indicators vary — some RIs use Key Performance Indicators (KPIs), while others link KPIs to qualitative narratives linking human stories and decision-making activities resulting from the ENVRI’s performance. Assessments blend quantitative and qualitative approaches, providing a picture of how ENVRI activities create value.

Assessing impact supports strategic planning, stakeholder engagement, and long-term sustainability.

We welcome abstracts on topics including:

• Conceptual and methodological approaches to impact assessment in ENVRIs
• Frameworks and tools for evaluating impact in ENVRIs
• Case studies and ongoing evaluations related to ENVRIs
• Communicating and using impact evidence for policy and funding related to ENVRIs.

Session 31: Flux measurements for immediate societal benefits

Conveners: George Burba (University of Nebraska, CarbonDew Community of Practice, LI-COR), John S. Kayode (Nigerian Army University), Sung-Ching Lee (Max Planck Institute for Biogeochemistry), Kosana Suvocarev (UC-Davis)

Direct flux measurements of heat, water, greenhouse gases (GHGs), and pollutants between the earth’s surface and its atmosphere unlock fair and equitable climate solutions across natural and built environments. Innovations and markets, as well as environmental policies based on such an approach, help resolve global climate and air quality challenges and fairly reward small and big stakeholders.

This session, organized collaboratively by academic research, non-profit organisations, and industry, welcomes ideas and examples of how to utilize direct flux measurements for tangible societal benefits, such as carbon removal, agriculture and forestry, reduction of anthropogenic emissions, various nature-based climate solutions, environmental impact management, and more.

For instance, these measurements can be applied to irrigation scheduling, soil and plant treatments, GHG reduction and sequestration, global warming potential, urban heat management, satellite and model products, industrial and urban emissions, severe weather impacts, air quality management, and can be used as a diagnostic tool for meeting net-zero targets by different organizations, regulatory, policy, and government agencies.

Join us to discuss developing a global paradigm for maximum-integrity, low-latency, and economically sound earth stewardship, anchored in direct flux measurements.

Session 32: Unlocking climate research solutions through co-design 

Conveners: Mariana Salgado (ICOS ERIC), Päivi Haapanala (LUKE - Natural Resources Institute Finland)

Why do some tools hinder research, web applications confuse users, or communications fail to engage communities? Often, it is the absence of user-informed insights, through the whole development process also known as co-design.  

This session explores how co-design helps define, test, and develop climate services and tools by integrating user needs throughout the process. Co-design fosters collaboration among researchers, policymakers, and other stakeholders, ensuring that services align with real-world demands and support effective climate action and policy.  

Aligned with the theme “Climate Action Services and Climate Policy,” the session invites researchers, designers, and developers to share case studies, insights, and lessons from co-design experiences. Projects in early stages seeking feedback are also welcome. Participants will learn to recognize when co-design is missing and how to involve stakeholders to create more usable, impactful outcomes.  

If you’re involving users in the development and refinement of your services, you are already co-designing. This session will help scientists and practitioners identify barriers that co-design can address and exchange practical approaches for integrating it into their work. Join us to share experiences and shape the future of climate solutions through collaborative, user-centered design.

Session 33: Science and arts: How to communicate science?

Conveners: Nina Buchmann (ETH Zurich), Timo Vesala (University of Helsinki), Jutta Holst (Lund University), Alexander Knohl (University Göttingen), Karlina Ozolina (ICOS ERIC), Manuel Acosta (CzechGlobe)

Climate change with its pronounced effects on global ecosystems and human societies is of global concern. While science aims to understand the intricate interplay of many drivers and their consequences on the climate system, global ecosystems, and societies, the knowledge about this complexity and potential solutions in the lay public is still limited. Many efforts have been made in the past to communicate causes and consequences of global climate change, complex process interactions, modulated by land and ocean management and urbanization. However, success stories on how to communicate science often get forgotten, the resources needed and the translation to local contexts thus often hamper their effectiveness and the longevity of beneficial impacts on the lay public. 

The session aims to foster an interdisciplinary exchange among researchers and artists working on communicating science related climate change, addressing different target audiences, using different approaches, including on-site or on-line, in-person or virtual, printed or programmed, visuals or acoustics. We welcome contributions focused on experiences, good or bad, tools and approaches, projects and programs, to learn from each other and to initiate a dialogue between the scientific community and the lay public.

Session 34: Manufacturers' session

Convener: Elena Saltikoff (ICOS ERIC)

This session is dedicated to instrument manufacturers and other companies to showcase their latest innovations and developments.