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Boron-CO2 workshop: testing and extending the limits of the foraminiferal boron proxy for seawater pH and atmospheric CO2 reconstructions

Bergen, Norway
Workshop report
Contact person
Eleni Anagnostou
E-Mail address


The goal of this workshop is to reach a community consensus on how we process foraminiferal boron isotope data for past pH/CO2 reconstructions, incorporating new data, with focus on assumptions required for different time periods in the Geologic record, and then re-interpret long term carbon-climate dynamics.

Please note that the exact dates and location for this workshop will be communicated as soon as this information is available. The dates in the calendar are placeholders only.


Date: 4 September
Location: Bergen University, Bergen, Norway.
The meeting will be held as a hybrid event, meaning there will be the possibility to participate online or in-person. 
Number of participants: 30 
There will be some funding to support ECR participants and/or participants from low- to middle income countries, generously provided by PAGES.

Workshop aims

Our principal aim is to build an accurate and self-consistent compilation of Phanerozoic CO2 records from boron isotopes. With this workshop, we will discuss consistent data processing techniques and preferred approaches to the generation of CO2 proxy data from boron isotopes, building on preliminary discussions during recent virtual meetings. We will produce a test dataset and agreed-upon best practice protocol(s). Further, we will discuss our plans for paper and data outputs and assign groups and deliverables. More broadly, the workshop aims to foster closer collaboration and coordination within the boron isotope community, and to ground new collaborative efforts to better constrain the proxy system, and hence past carbon cycle-climate interactions. Beyond the boron isotope community, our hope is that specific outputs (papers and datasets) will be beneficial within Palaeoclimatology, Climate and Earth science. 


Atmospheric carbon dioxide (CO2) is one of the key unknown environmental variables of the geological past, and directly informs our understanding of Earth’s climate sensitivity and the future trajectory of climate change. As a result, compilations of atmospheric CO2 records through time – such as Foster et al., 2017 and – are widely used and have been included in dedicated sections of the latest IPCC report.

Given increasing recognition of the importance of the boron isotope proxy for past atmospheric CO2 reconstruction, it is vital that as a community we mutually agree on consistent approaches to data generation and processing. Over the last decade, there have been several advances in how we obtain CO2 estimates from boron isotopes: advances in constraining and calculating seawater temperature and boron isotope composition, in deriving the necessary second carbonate system parameter, in how ‘vital effects’ are accounted for, in factoring in changing seawater chemistry, and in how uncertainties are propagated. As a result, even some of the newest studies are mutually inconsistent in some of their guiding assumptions.

This workshop is the culmination of a series of online workshops within the boron isotope community, aiming to compile and critically evaluate approaches used, from analytics to data processing.  Ultimately, we are looking to expand the horizons of the boron-CO2 proxy, and build an internally-consistent compilation of long-term CO2 change that provides reliable constraints on past climate. 

Application / registration

Register online:
Registration closes 20 June 


Eleni Anagnostou, GEOMAR Kiel, Germany (
Tali Babila, University of Southampton, UK (
Thomas Chalk, CEREGE Aix-en-Provence, France (
Michael Henehan, GFZ Potsdam, Germany (
Markus Raitzsch, AWI, Germany (

Please feel free to contact Eleni Anagnostou or Thomas Chalk (email addresses above) should you feel uncomfortable during the workshop.


For more information, please contact the organizers via email: