Session Themes

A.1 GHG Fluxes at ecosystem level: Soil and Woody-tissue

Manuel Acosta¹,
Eva Dařenová¹,
Jukka Pumpanen² 

¹ Global Change Research Institute, CAS, Czech Republic) ² University of Eastern Finland, Finland

Even though, last decades a significant advance regarding our knowledge on GHG fluxes from different ecosystem components (soil and woody-tissue) have been done, there still issues and shortcomings to be solved in order to improve our understanding of individual ecosystem components. Both, soil and woody-tissue are characterized by processes that are sensitive to environmental conditions and can depend on the current ecosystem state, including availability of substrates. Apart from temperature and water availability as main parameters influencing soil and woody-tissue fluxes rates, the combination of these mentioned parameters with physiological processes at component level can change the magnitude of rates (increased or decreased). Therefore, better understanding of these components at different environmental conditions and under various physiological processes is required. Moreover, precise quantifications are needed to improve GHG global budgets that are necessary for land-use management (agriculture, forestry) and global change strategies.

This section invites experimental and observatory studies of GHG fluxes (CO2, CH4 and N2O) from soil and/or woody-tissue components at ecosystem level and their influencing parameters. Studies about new techniques for determination of these components are also welcome.

A.2 Drivers of GHG fluxes from productive and managed peatlands: measurements, modelling and mitigation

Bart Kruijt¹,
Merit van den Berg²,
Christian Fritz³

¹Wageningen University, bart.kruijt@wur.nl  ²Vrije Universiteit Amsterdam, m.vandenberg@vu.nl  ³ Radboud Universiteit Nijmegen, c.fritz@science.ru.nl

Globally, 10–20% of peatlands have been drained for agriculture or forestry emitting close to 5% of global anthropogenic CO2 emissions. Some European countries report more than 60% of their emissions from agriculture and land use, land use change and forestry (LULUCF) originating from drained organic soils.

Peatland restoration can solve many problems related to drained peatlands but is only marginally implemented. Mitigation measures that sustain economically viable biomass production while reducing negative environmental impacts such as greenhouse gas (GHG) emissions while supporting ecosystem services are only currently studied. Long-term GHG flux data and studies of biogeochemical drivers of carbon fluxes are scarce. Management measures include productive use of wet peatlands, improved water management and novel approaches in conservation-focused rewetting projects.

We invite studies addressing all types of peatland management as well as their integration into GHG inventories. Work on all spatial scales from laboratory to national level addressing biogeochemical and biological aspects and experimental and modelling studies are welcome. Research on development of systems with details on viable value chains and income generation is of interest. We also invite contributions addressing policy coherence and identifying policy instruments for initiating and implementing new management practices on organic soils.

A.3 Stability of carbon pools following changes in climate and management in organic soils

Torsten Sachs, Geoforschungszentrum Potsdam, torsten.sachs@gfz-potsdam.de
Christian Fritz, Radboud University Nijmegen, c.fritz@science.ru.nl
Gerald Jurasinski, University of Rostock, gerald.jurasinski@uni-rostock.de

Organic soils, e.g. peatlands, harbour the world’s largest soil carbon stocks. Currently, peatland’s carbon stocks are under multiple pressures such as a changing climate, hydrological changes or nutrient loading with unknown consequences for their functioning as carbon sinks and stores, including the uptake or release of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).

However, it is not clear how the carbon reservoir will react to these pressures and how vulnerable or resilient these ecosystems are. Tipping points, thresholds, and system state changes are often referred to in the literature, but how much do we really know about these in the context of stability of carbon pools? Next to the better studied soil carbon dynamics short-term carbon pulses due to methane release or forest die-back following (summer) flooding. This session will focus on the observed or predicted changes on the biogeochemistry of wet peatlands, caused by external pressures such as climate change, rewetting or nutrient loading.

We invite studies concentrating, for example, on the effects of climate change, rewetting and nutrient loading on GHG or nutrient dynamics, peatland vegetation, atmosphere-biosphere interactions or carbon stock changes. Field observations, experimental, and modelling studies of both high- and low-latitude peatlands (semi-natural and/or managed) are welcomed.

B.1 Better constraining the European blue carbon stock

Richard Sanders, Dan Mayor, Stacey Felgate

Coastal vegetated ‘Blue Carbon’ habitats are an important carbon store which sit at the interface of terrestrial and marine science. They have the potential to sequester and store vast quantities of organic carbon (OC) on millennial time scales, but exhibit a high degree of spatial heterogeneity in terms of their efficiency and are under increasing threat from human activities (e.g. surface disturbance; acidification; coastal darkening; warming) such that, in some cases, they are actually sources of CO2 rather than sinks of OC. In order to better constrain the European blue carbon stock we require greater integration of methods, measurement-based estimates, and modelling studies.

In this session we solicit contributions relevant to this topic, including field studies, meta-analyses, modelling studies, and remote sensing work. We particularly encourage studies from within Europe, and those investigating the role of blue carbon habitats in the capture and storage of terrigenous OC.

B.2 The value chain of (surface) ocean CO2 measurements

Tobias Steinhoff¹, Dorothee Bakker², Thanos Gkritzalis³, Siv Lauvset⁴, Are Olsen⁵

¹ NORCE Norwegian Research Centre AS/Norway; GEOMAR Helmholtz Centre for Ocean Research Kiel/Germany (tsteinhoff@geomar.de ) ² University of East Anglia/UK (D.Bakker@uea.ac.uk) ³ Flanders Marine Institute/Belgium (thanos.gkritzalis@vliz.be) ⁴ University of Bergen/Norway (sivk@norceresearch.no) ⁵ University of Bergen/Norway (Are.Olsen@uib.no)

The oceans absorb around one quarter (2.5 ± 0.6 Pg C yr-1) of our annual anthropogenic CO2 emissions (Friedingstein et al., 2020). This number is partly based on a network of surface ocean CO2 observations (SOCONET/ICOS), which forms the basis of a value chain via synthesis (e.g. SOCAT) to mapped flux products (e.g. SOCOM ) to the Global Carbon Budget and the Intergovernmental Panel on Climate Change (IPCC). While the underlying network and synthesis activities are fragile and relies on community-driven efforts, they provide the best available information to decision makers for formulation of relevant policies. In 2016 the G7 ministers agreed on addressing ocean relevant challenges such as ocean observations. In order to contribute to the 2021 goals of the “G7 Future of the Seas and Oceans Initiative” we need a reinforced and sustainable value chain of ocean carbon observations.

We invite abstracts that show ways and future plans to foster the value chain of ocean carbon observations (surface and deep ocean) with the aim to better constrain global ocean CO2 uptake, to quantify ocean acidification and to determine their drivers.

B.3 New developments in estimates of the ocean sink for CO2

Andrew Watson¹, Susan Hartman²

¹University of Exeter, Exeter, UK  ²National Oceanography Centre, Southampton, UK

The ocean uptake of atmospheric carbon dioxide is a crucial term in the global carbon budget. There are many different ways of deriving the uptake from observations, involving surface CO2 measurements, interior biogeochemical observations, atmospheric oxygen/nitrogen ratios, ocean or atmospheric inverse calculations. However, these methods each measure subtly different quantities.

This session will invite new estimates, of ocean CO2 uptake, and its variability over time, or revisions of existing methods, and will to what extent the different methods are consistent with one another and with ocean carbon model calculations -- which calculate yet different quantities.

C.1 The fate of terrigenous organic carbon along the land-ocean aquatic continuum

Richard Sanders, Dan Mayor, Stacey Felgate

The flux of organic carbon from terrestrial landscapes to the open ocean via the land-ocean aquatic continuum (LOAC) is an important and changing component of the global carbon cycle. The fate of material entering the watershed affects its climate significance: conversion to CO2 via photolysis or respiration can add CO2 to the atmosphere leading to greenhouse gas (GHG) forcing, whilst burial within the sediments and blue carbon habitats or transport to the open ocean represents the physical relocation of organic carbon from one quasi-secure reservoir to another. The controls over these processes are well known (e.g. eutrophication; land use change; warming; intensification of the hydrological cycle) but an understanding of their integrated importance still eludes us.

In this session we solicit contributions relevant to this debate, ranging from lab studies, field studies, meta-analyses, and modelling work.  

C.2 Carbon cycle in the Mediterranean region: from the local to the regional scale

Paolo Cristofanelli¹, Silvano Fares¹, Josep Anton Morguì Castello², Michele Giani³, Alessio Collalti¹

¹ CNR, Italy ² University of Catalonya, Spain, ³ OGS, Italy

The Mediterranean region is recognized as a global “hot-spot” for what concerns the impact of climate change and the anthropogenic pressure on the environment. The Mediterranean region is characterized by very heterogeneous landscapes, biodiverse ecosystems and densely populated regions which make difficult to provide a consistent upscaling of 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, solid earth) to provide insights into carbon fluxes, including the impact of extreme events (e.g., 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.

C.3 Utilizing eddy covariance flux networks for improved understanding of carbon-water relationships at multiple spatial and temporal scales

Mirco Migliavacca: European Commission Joint Research Centre, mirco.migliavacca@ec.europa.eu Bert Gielen: ICOS ETC Executive Committee, bert.gielen@uantwerpen.be Margaret Torn: AmeriFlux Management, Lawrence Berkeley Nat Laboratory, mstorn@lbl.gov Sébastien Biraud: AmeriFlux Management, Lawrence Berkeley Nat Laboratory, scbiraud@lbl.gov George Burba: R.B. Daugherty Water for Food Global Institute & LI-COR Biosciences, gburba@unl.edu Jacob Nelson (early career scientist): BGC-Jena, jnelson@bgc-jena.mpg.de Kyle Delwiche (early career scientist): University of California-Berkeley, kdelwiche@berkeley.edu Koong Yi (early career scientist): Lawrence Berkeley National Laboratory, koongyi@gmail.com Marcy Litvak: The University of New Mexico, mlitvak@unm.edu

Continental-scale research infrastructures and flux networks (e.g., AmeriFlux, AsiaFlux, ChinaFlux, ICOS, NEON, OzFlux), as well as numerous smaller GHG flux networks, and individual sites, are often focused on measuring and modeling CO2 and other GHG exchange between ecosystem and atmosphere. Such measurements require a high-quality water vapor flux (evapotranspiration, ET) to help correctly compute the GHG exchange, and various soil and plant water measurements to help interpret the results.

Effectively, these GHG networks are also ET networks, often with a large set of supporting water measurements. However, beyond the important applications of computing and interpreting ecosystem-level GHG exchange, the water measurements at the GHG flux sites are rarely fully utilized.

This session, organized as a collaboration between ICOS, European Commission Joint Research Center, AmeriFlux Year of the Water Committee, and Water for Food Global Institute welcomes new ideas and existing examples of how to better utilize water measurements from the GHG flux sites. These can range broadly from instantaneous water use efficiency to long-term budgets, from turbulent transport theory to the inventory of specific measurements needs, and from site-specific process-level studies to integrating FLUXNET sites with proximal optical and remote sensing measurements for better predictability of ET and carbon-water coupling.

C.4 New developments in mapping regional CO2 fluxes

Meike Becker¹ & Henry Bittig²

¹ University of Bergen, meike.becker@uib.no ² Leibniz Institute for Baltic Sea Research (IOW) henry.bittig@io-warnemuende.de

Mapped fields of pCO2 and CO2 flux are an important ICOS product and essential building block for the global carbon budget. However, uncertainties still persist on smaller, regional scales (e.g., around the coastal ocean) or near boundaries (e.g., the land ocean interface, inland water bodies, or other transition zones). This session aims to combine knowledge and innovative ideas for estimating regional CO2 fluxes across all three ICOS domains and we particularly invite submissions that integrate observations across multiple sites. The goal is to collect contributions that will provide improved mapping results of regional CO2 fluxes both between atmosphere and water bodies (e.g., in lakes, rivers, estuarine, coastal and open ocean environments) and between atmosphere and land ecosystems.

D.1 Informing transformative change towards a sustainable future using integrated environmental research infrastructures

Thomas Dirnböck¹ & Karl-Heinz Erb²

¹Environment Agency Austria, Vienna, Austria; thomas.dirnboeck@umweltbundesamt.at ² Institute of Social Ecology (SEC), Vienna, Austria; karlheinz.erb@boku.ac.at

Avoiding undesirable trade-offs during the transformation towards a sustainable future requires a holistic research approach linking social, economic and environmental spheres. Monitoring and research infrastructures (RI) such as ICOS have significantly improved quantification of ecosystem greenhouse gas (GHG) balances. Thereby ICOS has paved the way for model-based regional to global data on current and future natural GHG fluxes and their underlying mechanisms, as well as their potential role as “nature-based-solutions” to the climate crisis.

However, the complexity behind ecosystem-climate interactions, including dynamics of land use, hampers the straightforward identification and implementation of solutions. We argue for complementary approaches that explicitly address potential trade-offs (most prominently biodiversity loss) as well as dynamics of society-nature interactions, for which the established data and knowledge bases provide an excellent starting point.

With the session, we aim at stimulating discussion towards such integrated approaches. The session is of transdisciplinary nature. We will compile presentations from policy research, social research, and biodiversity science, exemplifying different facets of the opportunities and challenges of integrating environmental research infrastructures.

D.2 Advances in nature-based negative emission technologies

Ivan Janssens¹, Sara Vicca¹, Mathilde Hagens² 

¹University of Antwerpen, ²Wageningen University 

All of IPCC’s pathways towards meeting the objectives of the Paris Agreement rely heavily on negative emission technologies, many of which still need to be proven empirically. In recent years, the scientific community has initiated many experiments to address the potential of these technologies, to identify eventual pitfalls, and how to overcome them and maximize carbon removal rates and/or their permanence. Many of the nature-based negative emission technologies also have substantial co-benefits for ecosystem services and SDG’s, while some imply risks that also need to be avoided.

The goal of this session is to bring together the knowledge learned during the past years and learn from each other to further optimize these nature-based negative emission technologies.

D.3 Enhancing the use of greenhouse gas observation systems to inform, enable and frame policy

Frank McGovern & Emmanuel Salmon

Data from observations are fundamental to understanding the drivers of climate change and its consequences. These include observations across the atmosphere, ocean and terrestrial domains. At a global level Parties to the UN Framework Convention on Climate Change (UNFCCC) have established the Global Climate Observation System (GCOS). This includes measurements of parameters which can provide information to support and inform mitigation and adaptation responses. GCOS is global in nature. However, the data are collected at regional, national and sub-national levels. The information provided from analysis of these data, in combination with related local observations as well as socio-economic and similar data, can have considerable value for informing responses at these levels. While good examples exist, and these are increasing, it is evident that the full potential for use of data from observation systems and particularly GHG observations have not been fully realised.

The aims of this session are to firstly explore examples of effective support of observations-based analysis for policy and the potential development of these in enhancing policy responses and actions. In addition, it would consider opportunities for development and areas where innovative solutions can enhance policy and actions. Abstracts are invited which may address topics in this area including: Informing effective actions to reduce GHG emissions, Observations in support of the UNFCCC COP26 outcomes and pledges, Beyond inventories: high resolution temporal and spatial analysis including hot spots, e.g., cities and conurbations, Quantification of managed and unmanaged carbon uptake and loss, Envisaging climate policies based on observational analysis, Links and lessons from air quality and epidemiology.

D.4 Community Engagement, Training and Outreach

Janne-Markus Rintala, Maiju Tiiri, Karlina Ozolina and Evi-Carita Riikonen, ICOS ERIC, Helsinki, Finland

Environmental Research Infrastructures, especially ones addressing Climate change, biodiversity loss etc. need to create innovative strategies and programmes for continuous professional development for teaching and supervision of future experts and users for their data. At ICOS, we provide educational material for everyone. These include on-line webinars and recordings, containing instructions for visualisations and analysis of ICOS data with Jupiter notebooks. For more information please see our Education website.

In this session we welcome abstracts for both poster and oral presentations that include examples and case studies in:

• Community building
• Outreach for society
• Best practices in gamification, problem based learning,  online training tools and platforms, etc.

E.1 Emission modelling and atmospheric monitoring of anthropogenic carbon emissions

Ivonne Albarus¹, Michel Ramonet², Philippe Ciais³

¹ LSCE/SUEZ, ivonne.albarus@lsce.ipsl.fr ² LSCE, michel.ramonet@lsce.ipsl.fr ³ LSCE, philippe.ciais@lsce.ipsl.fr

Strengthening the global response to climate change through the Global Stocktake entails a comprehensive review process of progress in the implementation of the Paris Agreement climate pledges (NDCs). Tracking progress implies robust assessment of mitigation actions before each NDC cycle. Assessment should be coherent across governance boundaries from the national level to the regional, state, and city levels. The combination of atmospheric GHG observations with granular emissions offers a unique approach to reach consistency across administrative boundaries, and timely information compared to traditional inventory reports. Atmospheric approaches also provide information on both anthropogenic and biogenic fluxes, resulting in a comprehensive system for policy makers.

Our session focuses on both atmospheric/emission modeling and instrumentation (groundbased, airborne, or from space) targeting fossil fuel GHG emissions, focusing on developments in urban scale dynamic inventories, inversion models, and national scale GHG inventories. We also sollicitate novel approaches at continental/national/urban scales targeting fossil fuel GHG emissions using various types of measurements (isotopes, radon, eddy flux, multi-species, …), aiming to extract fossil fuel emissions signals and to track progress in emission reductions from climate pledges at national and sub-national scales (e.g. PAUL, MERCI-CO2, CoCO2,…).

E.2 Towards operational monitoring of greenhouse gas emissions - the combination of satellite and in-situ data in an integrated system approach

Richard Engelen, ECMWF, richard.engelen@ecmwf.int Benjamin Poulter, NASA, benjamin.poulter@nasa.gov

To independently assess the progress of countries towards their targets as part of the Paris Agreement, an objective way to monitor anthropogenic CO2 emissions and their evolution over time is needed to support informed policy- and decision-making processes, at global, national, regional and local level. In Europe, the European Commission has taken a leading role by planning a new anthropogenic CO2 emissions monitoring & verification support capacity (CO2MVS) as part of the Copernicus programme. Similar efforts exist in other parts of the world (e.g., NASA’s Carbon Monitoring System) and global coordination has been set up through for instance the CEOS and WMO-IG3IS frameworks. Key element of these new observation-based monitoring capabilities is the integration of space-borne and in-situ observations with prior information through the use of Earth system modelling and data assimilation systems to enable the transparent and consistent quantitative assessment of CO2 emissions and their trends.

This session calls for presentations about the optimal combined use of satellite and in-situ observations in data assimilation/inverse modelling approaches to estimate fluxes and emissions of CO2 and/or CH4 at all scales. Specifically, the complementarity of the different types of observations as well as the challenges of combining these observations shall be addressed.

E.3 Ground-based remote sensing measurements of greenhouse gases and their application for carbon cycle studies, satellite and model validation and building MVS capacity

Mahesh Kumar Sha¹, Thorsten Warneke², Frank Hase³

¹ Royal Belgian Institute for Space Aeronomy, mahesh.sha@aeronomie.be, ² University of Bremen, warneke@iup.physik.uni-bremen.de, ³ Karlsruhe Institute of Technology, frank.hase@kit.edu.

Ground-based remote sensing observation techniques are an important component in the global observation system of greenhouse gases (GHGs) and other climate relevant gases. They provide partial and/or total column concentrations of GHGs from the surface to the top of the atmosphere. The Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change – Infrared Working Group (NDACC-IRWG) have been performing solar absorption measurements using high resolution Fourier transform infrared (FTIR) spectrometers for many years. Retrieval of total and/or partial column concentrations of GHGs and other climate relevant gases are performed from these measurements. Several portable low-resolution FTIR spectrometers, e.g. the EM27/SUN used by the Collaborative Carbon Column Observing Network (COCCON), complement TCCON and provide high quality reference total column data from globally distributed sites on a permanent or campaign basis. These networks provide the reference data sets that are used for satellite validation and model studies.

We invite presentations on new developments of FTIR remote sensing techniques supporting innovative scientific applications, on validation techniques for satellite and model data evaluation using FTIR observations, satellite GHG studies that rely on FTIR data for validation and on contributions towards building up monitoring and verification support (MVS) capacity.

F.1 The role of radon gas as tracer of atmospheric processes, air mass origin and indirect retrieval of greenhouse gas emissions

Annette Röttger¹, Claudia Grossi ², Katarzyna Wołoszczuk³, Scott Chambers⁴

¹ Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany, annette.roettger@ptb.de ² Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona, Spain, claudia.grossi@upc.edu ³ Central Laboratory for Radiological Protection, Konwaliowa 7, 03194 Warsaw, Poland, woloszczuk@clor.waw.pl ⁴ Environmental Research, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia, szc@ansto.gov.au

Naturally occurring radon is responsible for most human exposure to ionizing radiation. At the same time, radon is an efficient tracer of atmospheric boundary layer processes and air mass origin and facilitates the evaluation of transport models and estimation of integrated nocturnal greenhouse gas emissions. A metrological system for quantifying radon activity concentrations is therefore needed for atmospheric, climate, and radiation research. The particular challenge lies in the low activity concentrations typical of radon in outdoor air (~1 Bq m-3 to 100 Bq m-3), when there is currently no metrological traceability below 100 Bq m-3. Many monitoring stations (including those of the Integrated Carbon Observation System, ICOS) measure radon activity concentrations in contrasting physical settings using instruments with fundamentally different measurement principles. A robust metrology chain is therefore essential to compare observations between these sites made with existing or new instruments or use them collectively in model evaluation studies.

The session will summarise contemporary environmental radon metrology, with a particular focus on radon activity and radon flux measurements, the validation of radon flux models, and the creation of radon flux maps. Strengths and weaknesses of various applications of the radon tracer method for estimating regional GHG emissions will be presented.

F.2 Using the ICOS stations for investigating fluxes of reactive gases and aerosols in terrestrial ecosystems

Silvano Fares¹ & Christian Brümmer²

¹ National Research Council of Italy, Institute of Bioeconomy, Rome, Italy, silvano.fares@cnr.it ² Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany, christian.bruemmer@thuenen.de

Plant ecosystems exchange reactive trace gases, which play a major role in atmospheric chemistry. The ICOS network offers the opportunity to complement common observations of greenhouse gases with flux measurement of reactive gases such as nitrogen oxides (NOx), ozone, and volatile organic compounds (VOCs), 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 canopy region represents a dynamic and rapidly changing environment in which a myriad biological, chemical and physical processes occur over very short time and spatial scales. Advanced techniques of flux measurements provide good knowledge of the overall net fluxes of these compounds above canopies, while additional in-canopy measurements enable more detailed study and understanding of the individual processes and reactions driving these fluxes. These rapidly advancing measurements can support parametrization of models for a mechanistic understanding of in-canopy dynamics of deposition and emission of these reactive gases.

This session encourages the 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.

G.1 Abrupt changes in greenhouse gas fluxes in response to extremes: learning from observations to improve future projections

Ana Bastos¹, Thomas Pugh^2,3

¹ Max Planck Institute for Biogeochemistry, 07745 Jena, Germany. ² Department of Physical Geography and Ecosystem Science, Lund University, 22362 Lund, Sweden. ³ School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

The anthropogenic fingerprint of extreme weather events in the recent decades is now undisputed. Such events can disrupt terrestrial ecosystem functioning directly by imposing stress conditions and indirectly by increasing disturbance hazards and ecosystem susceptibility to those hazards. Extreme weather events are expected to become more frequent or intense, a trend superimposed on long-term increases in temperature and atmospheric dryness, as well as other environmental changes that can exacerbate plant stress. Repeated or longer extremes may therefore trigger cascading effects, leading to abrupt changes in ecosystem activity and composition, and consequently greenhouse-gas (GHG) fluxes. Limitations in modelling key processes (drought response, tree mortality, disturbance hazards, …) still challenge our ability to make robust projections of future changes in GHG fluxes in response to extremes. The increasing density and diversity of ecosystem monitoring observations provides opportunities to better identify modelling gaps and development needs, as well as to develop data-model fusion techniques.

In this session we welcome studies using observations, models or their integration to:

• evaluate ecological impacts of extreme events with a focus on CO2, CH4 and N2O fluxes,
• identify observational and/or modelling needs,
• analyse cascading effects and feedbacks across spatial and temporal scales, across all types of terrestrial ecosystems.

G.2 Effect of winter 2020 anthropogenic and climate anomalies on terrestrial, atmosphere, and ocean greenhouse gas exchange

Nicola Arriga¹, Mana Gharun², Corinna Rebmann³, Enrico Tomelleri⁴

¹ European Commission, Joint Research Centre (JRC), Ispra, Italy; nicola.arriga@ec.europa.eu ² ETH Zürich, Zürich, Switzerland; mana.gharun@usys.ethz.ch ³ UFZ, Leipzig, Germany; corinna.rebmann@ufz.de ⁴ Free University of Bozen-Bolzano, Bozen, Italy; enrico.tomelleri@unibz.it

During the first months of 2020 a series of special events at a range of spatial and temporal scales occurred, potentially impacting all ecosystems in Europe and the whole globe: in particular an anomalously warm winter occurred over much of Europe and the COVID-19 pandemic imposed a global lockdown of human activities that started immediately after and lasted for several months. Potential impact of such anthropogenic and climate anomalies on the exchange of greenhouse gases between the biosphere and the atmosphere is rather unclear.

The aim of this session is to collect studies oriented at detection of eventual marks of such events on biosphere-atmosphere exchange processes, and understanding physical processes underlying these marks. We particularly, but not exclusively, invite contributions related to the warm winter and pandemic events and based on observations collected through network infrastructure such as ICOS. We encourage contributions with an empirical or modelling focus at a range of spatial scales (from individual organism to the landscape and global scale). Finally, conjunction is particularly encouraged with recent climate anomalies, e.g., like the 2018 drought, to test the reliability of existing observations and analytical tools when dealing with climate and pollution extremes.

H. Manufacturers session

Elena Saltikoff, Ville Kasurinen, Sindu Raj Parampil, Janne-Markus Rintala, ICOS ERIC, Helsinki, Finland

This session is for instrument manufacturers to share their latest case studies and technical solutions, and to debate future industry trends and current challenges.