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Scientific meeting

Radiocarbon in the Anthropocene

Theo Murphy meeting organised by Professor Timothy Eglinton FRS, Dr Heather Graven, Professor Susan Trumbore and Professor Peter Raymond.

Add to Calendar 05/16/22 09:00 AM 05/17/22 05:00 PM United Kingdom (GMT) Radiocarbon in the Anthropocene <p>Theo Murphy meeting organised by Professor Timothy Eglinton FRS, Dr Heather Graven, Professor Susan Trumbore and Professor Peter Raymond.</p> Whittlebury Park
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Overview Organisers Programme

Overview

Theo Murphy meeting organised by Professor Timothy Eglinton FRS, Dr Heather Graven, Professor Susan Trumbore and Professor Peter Raymond.

This meeting brought together leading experts in the carbon cycle and global change science together with radiocarbon specialists in order to discuss the merits, feasibility and scope of a global-scale radiocarbon measurement and synthesis program for improved assessment of current, future and managed changes to the Earth's carbon cycle and greenhouse gas emissions.

Recorded audio of the presentations will be available on this page soon. Meeting papers will be published in a future issue of Philosophical Transactions of the Royal Society A. 

Credit: George Clerk
Credit: George Clerk

Organisers

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Timothy Eglinton FRS is Professor of Biogeoscience within the Department of Earth Sciences at ETH Zürich. Eglinton obtained a BSc in Environmental Science at the Plymouth Polytechnic, and MSc and PhD in Organic Geochemistry at the University of Newcastle-upon-Tyne.  Following postdoctoral research positions at Delft Technical University (Netherlands) and Oslo University (Norway), he joined Woods Hole Oceanographic Institution in 1989. He was a member of the Scientific Staff there until 2010, when he joined ETH. Professor Eglinton’s research program is centered on tracing the origin, cycling and legacy of biospheric carbon, and to understand the role of organic matter production, remineralization, transport, and burial as a component of the global carbon cycle. He focusses on processes on the continents and in the oceans, as well as the transfer of carbon between these systems. He has pioneered radiocarbon measurements at the molecular level as a tool to examine carbon cycle processes.   More information is available at: http://www.biogeoscience.ethz.ch/.

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven is a Reader in the Department of Physics and the Grantham Institute at Imperial College London. She worked previously at Scripps Institution of Oceanography, USA and at ETH Zurich, Switzerland. Her research focuses on the use of atmospheric measurements to understand the global carbon cycle and its response to human activities and climate change. She uses radiocarbon and stable carbon isotopes to distinguish fossil fuel and biogenic influences on carbon dioxide and methane, and to investigate carbon cycling in the ocean and land biosphere.

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Susan Trumbore is Director of the Processes Department at the MPI for Biogeochemistry in Jena and part-time Professor of Earth System Science at UC Irvine.  Her research uses radiocarbon produced by nuclear weapons testing to trace the flow of carbon through vegetation and soils. She has also applied the high sensitivity and throughput capabilities of AMS to apply radiocarbon in field labelling experiments to determine rates and pathways of C flow in ecosystems.  Professor Trumbore is the founding Editor-in-Chief of the new open access journal AGU Advances.  She helps lead the Amazon Tall Tower Observatory, a Brazilian/German project to study land-atmosphere-climate interactions in central Amazon tropical forest, and AquaDiva that studies how water connects the surface and subsurface biosphere in Critical Zone Observatories in central Germany. 

Professor Peter Raymond, Yale University, USA

Professor Peter Raymond, Yale University, USA

Schedule

09:00-13:30
Setting the scene – Radiocarbon and the global carbon cycle
8 talks

Chair

Professor Peter Raymond, Yale University, USA

Professor Peter Raymond, Yale University, USA

09:05-09:35
Radiocarbon and the changing global carbon cycle

Abstract

Anthropogenically-induced climate change is directly linked with perturbations to the global carbon cycle brought on by emissions of greenhouse gases associated with fossil fuel combustion and land-use change. Radiocarbon is a powerful tool for constraining carbon sources and carbon cycle dynamics in the Anthropocene given its absence in fossil fuels, and its depletion in other “pre-aged” C reservoirs (e.g., mineral soils, permafrost, deep ocean) that exchange with atmosphere and surface biosphere on centennial or longer timescales. Recent technological advances have greatly enhanced capacities for natural-abundance 14C measurement, and these advances coincide with burgeoning 14C databases, as well as the emergence of next-generation carbon cycle and earth system models. Implementation of comprehensive 14C measurement programs designed to provide crucial constraints on models, examine underlying processes, and detect (and quantify) the pace of change, are thus timely. By way of illustration, this presentation will highlight a new initiative that seeks to develop a first, national-scale 14C inventory spanning all major carbon pools. This information will be used to assess vulnerability of, and interplay between, different C pools, as well as provide a crucial benchmark against which to gauge past and future changes in carbon stocks and to constrain carbon-cycle models.

Speakers

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Timothy Eglinton FRS is Professor of Biogeoscience within the Department of Earth Sciences at ETH Zürich. Eglinton obtained a BSc in Environmental Science at the Plymouth Polytechnic, and MSc and PhD in Organic Geochemistry at the University of Newcastle-upon-Tyne.  Following postdoctoral research positions at Delft Technical University (Netherlands) and Oslo University (Norway), he joined Woods Hole Oceanographic Institution in 1989. He was a member of the Scientific Staff there until 2010, when he joined ETH. Professor Eglinton’s research program is centered on tracing the origin, cycling and legacy of biospheric carbon, and to understand the role of organic matter production, remineralization, transport, and burial as a component of the global carbon cycle. He focusses on processes on the continents and in the oceans, as well as the transfer of carbon between these systems. He has pioneered radiocarbon measurements at the molecular level as a tool to examine carbon cycle processes.   More information is available at: http://www.biogeoscience.ethz.ch/.

09:35-09:50
Discussion
09:50-10:20
How radiocarbon could help the historical global carbon budget

Abstract

The global carbon budget assesses all components of the anthropogenic perturbation on the carbon cycle. It is now well understood that the atmospheric CO2 increase amounts to only about 50% of the global emissions from human activities (fossil fuel combustion and land use changes). The oceans and the terrestrial ecosystems are acting as carbon sinks, removing together about 50% of the anthropogenic emissions. While the mechanisms for these carbon sinks are clearly identified and relatively well quantified for the ocean, the picture is less clear for the land sink. As atmospheric CO2 increases, so does plant photosynthesis, leading to increased carbon stored in vegetation first but then in litter and soils. These increase in carbon stocks will eventually lead to an increase in ecosystem respiration.  The land sink can hence be seen as the transient imbalance between a growing photosynthesis term and a delayed growing respiration term. The lag between the growth of these fluxes is directly controlled by the residence time of carbon in vegetation and soils. Radiocarbon has the potential to help better quantifying the “active” soil carbon, that is the fraction of the global soil carbon that is already affected by the atmospheric CO2 driven perturbation. 

Speakers

Professor Pierre Friedlingstein

University of Exeter, United Kingdom

Professor Pierre Friedlingstein

University of Exeter, United Kingdom

Professor Pierre Friedlingstein holds a Chair in Mathematical Modelling of the Climate System at the University of Exeter and is also Directeur de Recherche at the Laboratoire de Météorologie dynamique, CNRS, France. He has 30 years research experience in the field of global carbon and biogeochemical cycles and global climate change. He received the Alexander von Humbold Research award in 2019, the Vladimir Ivanovich Vernadsky Medal of the European Geosciences Union in 2020 and was ranked 3rd in the Reuters list of the world’s top climate scientists in 2021. He is an international leader in the understanding of the feedbacks between the carbon cycle and the climate system. Over the last decade, he led several international activities, in particular the Global Carbon Budget and the Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP). He is member of the Joint Science Committee of the World Climate Research Programme and was lead author for the Intergovernmental Panel on Climate Change.

10:20-10:35
Discussion
10:35-11:00
Break
11:00-11:30
Past and future changes in atmospheric 14C and 13C

Abstract

The ratio of 14C/C in atmospheric CO2 (Δ14CO2) has changed dramatically over the Industrial Period due to human activities. Emissions of CO2 from fossil fuel combustion reduce Δ14CO2 because 14C is absent in million-year-old fossil fuels, which have been stored for much longer than the radioactive decay time of 14C. Atmospheric Δ14CO2 rapidly increased in the 1950s to 1960s because of 14C produced during nuclear bomb testing. The resulting trends in Δ14C in atmospheric CO2 are influenced not only by these human emissions but also by natural carbon exchanges that mix carbon between the atmosphere and ocean and terrestrial ecosystems. This mixing caused Δ14CO2 to return toward preindustrial levels in the first few decades after the spike from nuclear testing. More recently, as the bomb 14C excess is now mostly well mixed with the decadally overturning carbon reservoirs, fossil fuel emissions have become the main factor driving further decreases in atmospheric Δ14CO2. Presently, Δ14CO2 is dropping below the preindustrial level of 0 per mil. In the future, Δ14CO2 will continue to change. The changes are mainly determined by global fossil fuel emissions. We present simulations of future atmospheric Δ14CO2 and discuss their effect on other carbon reservoirs and various applications using 14C.

Speakers

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven is a Reader in the Department of Physics and the Grantham Institute at Imperial College London. She worked previously at Scripps Institution of Oceanography, USA and at ETH Zurich, Switzerland. Her research focuses on the use of atmospheric measurements to understand the global carbon cycle and its response to human activities and climate change. She uses radiocarbon and stable carbon isotopes to distinguish fossil fuel and biogenic influences on carbon dioxide and methane, and to investigate carbon cycling in the ocean and land biosphere.

11:30-11:45
Discussion
11:45-12:15
Lightning Talks
12:15-12:30
Discussion
12:30-13:30
Lunch
13:30-17:00
Assessing capabilities in radiocarbon observation and modelling
8 talks

Chair

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven is a Reader in the Department of Physics and the Grantham Institute at Imperial College London. She worked previously at Scripps Institution of Oceanography, USA and at ETH Zurich, Switzerland. Her research focuses on the use of atmospheric measurements to understand the global carbon cycle and its response to human activities and climate change. She uses radiocarbon and stable carbon isotopes to distinguish fossil fuel and biogenic influences on carbon dioxide and methane, and to investigate carbon cycling in the ocean and land biosphere.

13:30-14:00
AMS and future advances in 14C measurement

Abstract

The technical evolution of Accelerator Mass Spectrometry (AMS) over the last ten years has boosted research with radioactive tracers. Dedicated high performing instruments are covering the needs of a wide user community to get reliable isotopic ratio measurements with uncertainties in the range of 10 - 20 radiocarbon years. But not only the analytic quality has increased. Several established AMS laboratories have renewed their instrumentation and new laboratories have started operation. Thus, the overall measurement capacity has now reached a volume making research possible requiring large number of individual analyses. It enables the analysis of tree ring records in annual resolution which will be most beneficial not only in the classical dating applications. The access to direct CO2 gas measurements is essential to applications that need capability of analysis of samples in the low ug range. This is of particular importance in connection with global carbon cycle studies. Radiocarbon in the ocean has also gained importance. Bomb produced radiocarbon is still traceable in the global oceans, and detailed analyses will help to reinforce the data basis on ocean circulation. Recent progress in sample preparation makes it much easier to analyse large sample series with high data quality.

Speakers

Professor Dr Hans-Arno Synal

ETH Zürich, Switzerland

Professor Dr Hans-Arno Synal

ETH Zürich, Switzerland

Hans-Arno Synal is an accelerator mass spectrometry specialist with background in nuclear and atomic physics and he studied Physics at Rheinische Friedrich-Wilhelms-Universität Bonn where he graduated in 1985. He moved to Swiss Federal Institute of Technology Zurich (ETHZ) and obtained his PhD on “Accelerator mass spectrometry with 36Cl” in 1989. Following a post-doctoral fellowship at the Institute of Intermediate Energy, ETH Zurich, he became research scientist at the Paul Scherrer Institute. Since 2008, he is heading the ETH Laboratory of Ion Beam Physics (LIP) and he was appointed as honorary Professor at ETH Zurich in 2011.

14:00-14:15
Discussion
14:15-14:45
Modelling radiocarbon dynamics in the Earth system to infer process rates in the global carbon cycle

Abstract

Radiocarbon can be used as a tracer of the global carbon cycle to infer rates of exchange among different reservoirs. It can also be used to improve the representation of different processes in Earth system models (ESMs) and test their predictions. Although many ESMs do not represent radiocarbon explicitly, it is now possible to compute the dynamics of radiocarbon based on existing model output such as the Coupled Model Intercomparison (CMIP) archive. This contribution will introduce a new set of concepts and methods to obtain radiocarbon dynamics from numerical model output, and to compare radiocarbon observations in the context of an underlying distribution of carbon ages. These concepts provide new opportunities to integrate radiocarbon observations with ESMs and to better forecast future trajectories of the global carbon cycle as well as the fate of carbon of fossil fuel origin.

Speakers

Dr Carlos A. Sierra

Max Planck Institute for Biogeochemistry, Jena, Germany and Swedish University of Agricultural Sciences, Uppsala, Sweden

Dr Carlos A. Sierra

Max Planck Institute for Biogeochemistry, Jena, Germany and Swedish University of Agricultural Sciences, Uppsala, Sweden

Dr Carlos A. Sierra is group leader at the Max Planck Institute for Biogeochemistry and Guest Professor at the Swedish University of Agricultural Sciences. His main research interest is the development of concepts and models for representing processes in the terrestrial carbon cycle. He is particularly interested in the quantification of the time it takes for carbon to cycle among different reservoirs, and to develop approaches to manage the carbon cycle in the context of climate change mitigation.

14:45-15:00
Discussion
15:00-15:30
Break
15:30-16:00
Estimating Fossil CO₂ Emissions from Atmospheric Measurements of Radiocarbon in CO₂

Abstract

Fossil-derived CO₂ is completely devoid of ¹⁴C. Therefore, the ¹⁴C content of atmospheric CO₂, expressed as Δ¹⁴CO₂, is a very good estimator for recently emitted fossil CO₂. Measured gradients of Δ¹⁴CO₂ in the atmosphere can be used to disentangle fossil and non-fossil CO₂ fluxes at local, regional, and national scales. At the local scale, this can be used to estimate fossil CO₂ emissions from total CO₂ enhancements observed by other platforms such as in situ sensors and satellites. At regional and national scales, Δ¹⁴CO₂ measurements can be used to construct fossil CO₂ emission estimates with accuracy comparable to “bottom-up” inventory estimates. Besides providing an independent verification of emission inventories, such regional estimates also play a crucial role in diagnosing the terrestrial carbon cycle. Accurate atmosphere-based estimates of fossil CO₂ emissions at urban to regional scales are not possible from CO₂ measurements alone, irrespective of the measurement platform, due to interference from the land biosphere. A coordinated effort at measuring and modelling Δ¹⁴CO₂ in the atmosphere can therefore lead to accurate atmosphere-based estimates of fossil CO₂ emissions, in direct support of regional and national emission verification and mitigation efforts.

Speakers

Dr Sourish Basu

Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt MD, USA

Dr Sourish Basu

Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt MD, USA

Dr Sourish Basu is an atmospheric inverse modeler and carbon cycle scientist at the Global Modeling and Assimilation Office at the NASA Goddard Space Flight Center in the US. His scientific interest is in diagnosing carbon cycle processes from atmospheric measurements of trace gases such as CO₂, CH₄ and their isotopologues, such as ¹⁴C (radiocarbon) in CO₂ and ¹³C in CH₄. He is a member of the Science Team of NASA's Orbiting Carbon Observatory 2 (OCO2) satellite instrument. Prior to his current position, he was a research scientist at the National Oceanic and Atmospheric Administration (NOAA) in Boulder, USA, and prior to that at SRON Netherlands Institute for Space Research in Utrecht, The Netherlands. He obtained his PhD in Physics from Cornell University, USA in 2009.

16:00-16:15
Discussion
16:15-16:45
Lightning Talks
16:45-17:00
Discussion
09:00-13:30
Using radiocarbon to understand carbon cycle processes and change
8 talks

Chair

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Timothy Eglinton FRS is Professor of Biogeoscience within the Department of Earth Sciences at ETH Zürich. Eglinton obtained a BSc in Environmental Science at the Plymouth Polytechnic, and MSc and PhD in Organic Geochemistry at the University of Newcastle-upon-Tyne.  Following postdoctoral research positions at Delft Technical University (Netherlands) and Oslo University (Norway), he joined Woods Hole Oceanographic Institution in 1989. He was a member of the Scientific Staff there until 2010, when he joined ETH. Professor Eglinton’s research program is centered on tracing the origin, cycling and legacy of biospheric carbon, and to understand the role of organic matter production, remineralization, transport, and burial as a component of the global carbon cycle. He focusses on processes on the continents and in the oceans, as well as the transfer of carbon between these systems. He has pioneered radiocarbon measurements at the molecular level as a tool to examine carbon cycle processes.   More information is available at: http://www.biogeoscience.ethz.ch/.

09:00-09:30
Radiocarbon and permafrost dynamics

Abstract

Soils in the northern permafrost region store 1,460 to 1,600 petagrams of organic carbon, almost twice the amount contained in the atmosphere. Permafrost thaw and the microbial decomposition of organic carbon is considered one of the largest positive feedbacks from terrestrial ecosystems to climate in a warmer world. Yet, the rate of release is highly uncertain but crucial for predicting the strength and timing of this carbon cycle feedback. This was studied in a tundra landscape undergoing widespread permafrost thaw, where net ecosystem carbon exchange and the radiocarbon age of ecosystem respiration were measured to determine the influence of old carbon loss on ecosystem carbon balance. Sustained transfers of carbon to the atmosphere must come from old carbon, which forms the bulk of the permafrost carbon pool that accumulated over thousands of years. Isotope partitioning of respiration sources using radiocarbon revealed highest old carbon release with increased thaw and where soils became drier. These data document significant losses of soil carbon with permafrost thaw that, over decadal time scales that could make permafrost a large biospheric carbon source in a warmer world. This will also be influenced by site soil moisture/drainage that is an indirect consequence of changing permafrost.

Speakers

Professor Dr Ted Schuur

Northern Arizona University, Flagstaff, USA

Professor Dr Ted Schuur

Northern Arizona University, Flagstaff, USA

Dr Ted Schuur is a Regents’ Professor in the Center for Ecosystem Science and Society at Northern Arizona University. He is an ecologist who has studied links between ecosystems and climate in locations across Alaska and the Arctic. His work on this topic has included more than two decades of field research and, in this time, has resulted in more than 200 peer-reviewed publications in high-impact journals. He is the also the lead investigator for the Permafrost Carbon Network, an international consortium of researchers aimed at synthesizing new knowledge on permafrost carbon and climate. He graduated Magna Cum Laude with a BS from the University of Michigan and he received a PhD from the University of California-Berkeley. He is an elected a fellow of the American Geophysical Union.

09:30-09:45
Discussion
09:45-10:15
Radiocarbon and the Cycling of Dissolved Organic Matter (DOM)

Abstract

The >5000-year radiocarbon age of much of the 630±30 Pg C marine dissolved organic carbon (DOC) reservoir remains an enigma in the marine carbon cycle. Current models hypothesize that radiocarbon (14C) depleted DOC (DOCr) is present as a uniform reservoir with a constant 14C signature throughout the ocean that is the result of the persistence of DOCr over multiple ocean mixing cycles. However, key requirements of this model, including direct observations of DOCr with similar 14C signatures in the surface and deep ocean, have never been demonstrated. Furthermore, the diversity of radiocarbon signatures in marine DOM remains unconstrained. Studies have fractionated DOM into operationally defined fractions to interrogate the radiocarbon distribution in DOM, while others have approached this problem using mixing models to reproduce the signatures observed during the serial oxidation of DOM and DOM fractions. Some of these analyses provide conflicting results. A few studies have also attempted compound specific radiocarbon measurements and these have primarily targeted the most labile fraction, demonstrating unequivocally that recently produced DOM does accumulate. This talk will summarise previous results, identify what is still unknown, and discuss where opportunities exist for making progress toward constraining the cycling of carbon through marine DOM.

Speakers

Professor Lihini Aluwihare

Scripps Institution of Oceanography, UC San Diego, San Diego, USA

Professor Lihini Aluwihare

Scripps Institution of Oceanography, UC San Diego, San Diego, USA

Professor Lihini Aluwihare, a chemical oceanographer, was born in Sri Lanka and lived in Zambia before moving to the United States for college and post-graduate studies. Arriving at Scripps Institution of Oceanography at UC San Diego in 2000, she studied the cycling of carbon and nitrogen in the oceans using light isotope tools and organic matter chemical characterisation. Aluwihare received her bachelor’s in chemistry and philosophy from Mount Holyoke College and her Ph.D. in Oceanography from the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography.  Her research attempts to read the messages encoded in molecules that maintain microbial life, facilitate ecosystem interactions, and contribute to long-term carbon and nutrient storage. A common theme that underpins her work is her commitment to developing new analytical tools and research frameworks to provide new perspectives on dissolved organic matter cycling in aquatic environments. 

10:15-10:30
Discussion
10:30-11:00
Break
11:00-11:30
Recent changes in ocean DI14C and implications for ocean circulation

Abstract

Anthropogenic perturbations from fossil fuel burning and nuclear bomb testing have created a useful transient tracer of ocean circulation from measurements and modelling of dissolved 14C. The atmospheric 14C/C ratio (∆14C) peaked in the early 1960s and has decreased now to nearly pre-bomb levels. We present the first analysis of a new decade of observations from 2007 to 2016 which gives a comprehensive overview of the changes in ocean ∆14C since the 1990s. Surface ocean ∆14C decreased from the 2000s to 2010s at a similar rate as from the 1990s to 2000s (20‰/decade). In contrast to the period from the 1990s to the 2000s when denser waters gained 14C from the continued downward ventilation of bomb 14C, the extent of positive ∆14C between the 2000s to 2010s is much reduced. Comparison to two ocean models, the Community Earth System Model v2 (CESM2) and the Estimating the Climate and Circulation of the Ocean v4 (ECCOv4), shows evidence from ∆14C of decadal variability in the ventilation of Southern Ocean intermediate waters. The decrease in surface tracers from the 2000s to the 2010s is consistently stronger in observations than in these models, which may result from a reduction in vertical transport and mixing due to stratification.

Speakers

Joanna Lester

Imperial College London, United Kingdom

Joanna Lester

Imperial College London, United Kingdom

Dr Joanna Lester is a researcher and consultant in oceanography. She recently completed her PhD looking at recent changes in oceanic radiocarbon and CFCs. She used a selection of ocean models and tracer observations collected over the past 30 years to examine tracer changes and investigate their internal variability. Dr Lester collected radiocarbon samples across two Atlantic hydrographic sections as part of the research. Her work as a consultant has included many large-scale coastal modelling projects, shipping studies and innovation projects.

11:30-11:45
Discussion
11:45-12:15
Paleo-carbon cycle perspectives from radiocarbon

Abstract

Along with improving the accuracy of the radiocarbon chronometer, recording the natural variations of 14C is essential for our understanding of climate processes, solar activity, geophysics, and the biogeochemical carbon cycle. Marine radiocarbon integrates the influences of changing radiocarbon production, air-sea gas exchange at the sea surface, transport times within the ocean interior, and the mixing of water parcels with different transit times from the sea surface, and different sea-surface sources. The study of the variations of 14C in marine archives such as reef or deep-sea cores makes it possible to complete the calibration of the radiocarbon as well as to quantify the variations of the carbon cycle by comparing the atmospheric and oceanic series. Over the last decade, the possibility to date extremely small amounts of carbonates has allowed new research possibilities, but also led to the discovery of new sources of complexity, unaccounted or neglected previously. This implies revisiting and modifying a significant proportion of 14C records obtained previously. This revolution is similar to previous ones linked to other technological improvements (e.g., switch from beta counting to AMS for 14C in the 80s and from alpha counting to mass spectrometry for U-Th in the 90s).

Speakers

Professor Edouard Bard, Collège de France, France

Professor Edouard Bard, Collège de France, France

Edouard Bard is the Professor Chair in Climate and Ocean Evolution at the Collège de France, a member of the French Académie des Sciences and of the Academia Europaea, a foreign member of the US National Academy of Sciences and of the Royal Academy of Belgium, and an honorary fellow of EGU, AGU, GSA and GS-EAG. Edouard Bard defended in 1987 his PhD focused on radiocarbon by accelerator mass spectrometry on modern seawater and on fossil foraminifera from marine sediments. He then worked as a postdoc at Lamont-Doherty Earth Observatory (Columbia University, New-York) using U-Th dating of corals by mass spectrometry to study deglacial sea level changes and to extend the radiocarbon calibration beyond the Holocene. He served as a member of the IntCal working group since 1993. He leads the AixMICADAS radiocarbon unit and participate to programs on cosmogenic nuclides in polar ice cores by means of the ASTER 5MV facility, both AMS being located at CEREGE in Aix-en-Provence.

12:15-12:30
Discussion
12:30-13:30
Lunch
13:30-17:00
Using radiocarbon to constrain anthropogenic carbon emissions and uptake
7 talks

Chair

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Susan Trumbore is Director of the Processes Department at the MPI for Biogeochemistry in Jena and part-time Professor of Earth System Science at UC Irvine.  Her research uses radiocarbon produced by nuclear weapons testing to trace the flow of carbon through vegetation and soils. She has also applied the high sensitivity and throughput capabilities of AMS to apply radiocarbon in field labelling experiments to determine rates and pathways of C flow in ecosystems.  Professor Trumbore is the founding Editor-in-Chief of the new open access journal AGU Advances.  She helps lead the Amazon Tall Tower Observatory, a Brazilian/German project to study land-atmosphere-climate interactions in central Amazon tropical forest, and AquaDiva that studies how water connects the surface and subsurface biosphere in Critical Zone Observatories in central Germany. 

13:30-14:00
Prospects and challenges to monitor fossil CO2 at the European scale

Abstract

The European Integrated Carbon Observation System (ICOS) collects atmospheric air samples at 17 sites and analyses their 14CO2 activity as part of its atmospheric observation program. These samples allow for monitoring atmospheric 14CO2 trends and determining the amount of CO2 recently added to the atmosphere by fossil fuel combustion (ffCO2). This talk presents the latest ICOS 14CO2 data and discusses how they are affected by nuclear or local 14C emissions. We discuss possible correction or avoidance approaches and their associated uncertainties. Furthermore, the talk addresses the potential role that a 14CO2 observation network could play for the currently emerging satellite-based Copernicus CO2 Monitoring and Verification System and presents new results for using CO and NOx as fossil fuel CO2 surrogate tracers.

Speakers

Dr Samuel Hammer, Heidelberg University, Germany

Dr Samuel Hammer, Heidelberg University, Germany

Samuel Hammer is a research scientist and Head of the Central Radiocarbon Laboratory (CRL) of the Integrated Carbon Observation System (ICOS) research infrastructure at Heidelberg University. Since the mid-2000s, he worked with urban greenhouse gas observations and introduced the continuous atmospheric hydrogen and in-situ FTIR observations at Heidelberg. His research focuses on interpreting 14C-based fossil-fuel CO2 observations and their uncertainties. In the ICOS pilot station framework, he and the ICOS CRL team investigates the applicability and the challenges of other fossil-fuel CO2 proxies like, e.g. CO, NOx, and APO.

14:00-14:15
Discussion
14:15-14:45
Radiocarbon in urban regions

Abstract

All nations have committed to reducing their greenhouse gas emissions through the Paris Agreement and their Nationally Determined Contributions.  While the policy directives are at the national level, the policies needed to meet these obligations are enacted at local scales.   Cities are therefore often leading the way in greenhouse gas emission mitigation efforts, both to address the climate challenge and for the many associated co-benefits.  To achieve these goals, detailed local emissions information resolved in space, time and by source sector, is needed both to assess the potential of carbon mitigation strategies and evaluate the success of such strategies.

State-of-the-art methods for determining local emissions use a combination of bottom-up inventory methods based on activity data and atmospheric observations of greenhouse gases.  A key challenge to atmospheric observations is that it is difficult to distinguish natural and anthropogenic CO2 emissions from concentration measurements alone. Radiocarbon observations resolve this challenge by separating fossil fuel derived CO2 (CO2ff) from other CO2 sources.  Studies from Indianapolis, Sacramento and Auckland demonstrate the application of radiocarbon observations to infer urban CO2ff fluxes and show that urban CO2ff emissions can be determined to better than 10% uncertainty.

Speakers

Dr Jocelyn Turnbull, University of Colorado at Boulder, USA

Dr Jocelyn Turnbull, University of Colorado at Boulder, USA

Jocelyn Turnbull holds joint appointments as a Senior Scientist at GNS Science, New Zealand and a Research Associate at the University of Colorado at Boulder, USA. She leads the Rafter Radiocarbon Laboratory at GNS Science, the world’s oldest continuously operating radiocarbon facility. The laboratory maintains expertise in a wide range of radiocarbon applications, and Jocelyn’s research is primarily on the modern carbon cycle, particularly fossil fuel derived CO2. She uses radiocarbon and related tracers to understand the sources and sinks of greenhouse gases at the local, urban and regional scales. Current projects include CarbonWatch-NZ which aims to evaluate New Zealand’s natural and anthropogenic carbon budget; INFLUX, the Indianapolis Flux Project where methods for evaluating urban greenhouse gas emissions are being developed; and SOAR Southern Ocean Atmospheric Radiocarbon which uses radiocarbon measurements to understand the dynamics of Southern Ocean carbon exchange.

14:45-15:00
Discussion
15:00-15:30
Break
15:30-16:00
Using radiocarbon to understand opportunities and challenges for soil carbon sequestration

Abstract

Soils are the largest terrestrial pool of carbon and a large fraction of that carbon actively cycles between the soil and atmosphere. Even small land use, land management and climatic perturbations can have a large impact on the annual flux between the atmosphere and the soil. Radiocarbon measurements of bulk soil organic matter and various fractions of soil organic matter have revealed fundamental insights into the rate of loss or accumulation of soil carbon on human relevant time scales. These measurements have greatly improved our conceptual understanding of soil carbon cycling and have helped constrain numerical models of the soil carbon cycle. In this presentation, I will highlight several examples where radiocarbon has uniquely informed soil carbon cycle science and discuss where radiocarbon measurements can be better utilized to address emerging questions around soil carbon management for climatic benefits. 

Speakers

Dr Jonathan Sanderman, Woods Hole Research Center, USA

Dr Jonathan Sanderman, Woods Hole Research Center, USA

Jonathan Sanderman is an Associate Scientist at the Woods Hole Research Center. Dr Sanderman is a biogeochemist who specialises in understanding how soil carbon and nutrient cycles have been altered by land-use and climate change. He is particularly interested in understanding the carbon sink capacity of soils and coastal sediments and whether or not these sinks can be managed to mitigate climate change. His more recent work has involved applying emerging concepts in data analytics to soil science to increase the availability of soil information and decrease the cost of monitoring and verification of soil carbon and soil health projects. Prior to joining the Center, Dr Sanderman spent six years as a research scientist at the Australian Commonwealth Scientific and Industrial Research Organization focusing on soil carbon sequestration in agricultural soils. Dr Sanderman holds a BS from Brown University and a PhD from the University of California, Berkeley.

16:00-16:15
Discussion
16:15-17:00
Panel discussion and overview

Speakers

Professor Peter Raymond, Yale University, USA

Professor Peter Raymond, Yale University, USA

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven, Imperial College London, UK

Dr Heather Graven is a Reader in the Department of Physics and the Grantham Institute at Imperial College London. She worked previously at Scripps Institution of Oceanography, USA and at ETH Zurich, Switzerland. Her research focuses on the use of atmospheric measurements to understand the global carbon cycle and its response to human activities and climate change. She uses radiocarbon and stable carbon isotopes to distinguish fossil fuel and biogenic influences on carbon dioxide and methane, and to investigate carbon cycling in the ocean and land biosphere.

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Professor Timothy Eglinton FRS

Department of Earth Sciences, ETH Zürich, Switzerland

Timothy Eglinton FRS is Professor of Biogeoscience within the Department of Earth Sciences at ETH Zürich. Eglinton obtained a BSc in Environmental Science at the Plymouth Polytechnic, and MSc and PhD in Organic Geochemistry at the University of Newcastle-upon-Tyne.  Following postdoctoral research positions at Delft Technical University (Netherlands) and Oslo University (Norway), he joined Woods Hole Oceanographic Institution in 1989. He was a member of the Scientific Staff there until 2010, when he joined ETH. Professor Eglinton’s research program is centered on tracing the origin, cycling and legacy of biospheric carbon, and to understand the role of organic matter production, remineralization, transport, and burial as a component of the global carbon cycle. He focusses on processes on the continents and in the oceans, as well as the transfer of carbon between these systems. He has pioneered radiocarbon measurements at the molecular level as a tool to examine carbon cycle processes.   More information is available at: http://www.biogeoscience.ethz.ch/.

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Dr Susan Trumbore

MPI Biogeochemistry Jena, Germany

Professor Susan Trumbore is Director of the Processes Department at the MPI for Biogeochemistry in Jena and part-time Professor of Earth System Science at UC Irvine.  Her research uses radiocarbon produced by nuclear weapons testing to trace the flow of carbon through vegetation and soils. She has also applied the high sensitivity and throughput capabilities of AMS to apply radiocarbon in field labelling experiments to determine rates and pathways of C flow in ecosystems.  Professor Trumbore is the founding Editor-in-Chief of the new open access journal AGU Advances.  She helps lead the Amazon Tall Tower Observatory, a Brazilian/German project to study land-atmosphere-climate interactions in central Amazon tropical forest, and AquaDiva that studies how water connects the surface and subsurface biosphere in Critical Zone Observatories in central Germany.