Radiocarbon Measurements Reveal Underestimated Fossil CH₄ and CO₂ Emissions in London
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1.
Imperial College London
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2.
ETH Zurich
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3.
University of California, Irvine
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4.
University of Bristol
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5.
California Institute of Technology
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6.
Heidelberg University
Abstract
Radiocarbon (14C) is a powerful tracer of fossil emissions because fossil fuels are entirely depleted in 14C, but observations of 14CO2 and especially 14CH4 in urban regions are sparse. We present the first observations of 14C in both methane (CH4) and carbon dioxide (CO2) in an urban area (London) using a recently developed sampling system. We find that the fossil fraction of CH4 and the atmospheric concentration of fossil CO2 are consistently higher than simulated values using the atmospheric dispersion model NAME coupled with emission inventories. Observed net biospheric uptake in June–July is not well correlated with simulations using the SMURF model with NAME. The results show the partitioning of fossil and biospheric CO2 and CH4 in cities can be evaluated and improved with 14C observations when the nuclear power plants influence is negligible.
Copyright and License
© 2023 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Acknowledgement
This project was funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement 67910). NAEI inventories were retrieved from the NAEI website: © Crown 2022 copyright Defra & BEIS via naei.beis.gov.uk, licenced under the Open Government Licence (OGL).
Funding
This project was funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement 67910).
Contributions
Conceptualization: Giulia Zazzeri, Heather Graven.
Data curation: Giulia Zazzeri, Xiaomei Xu, Eric Saboya, Liam Blyth, Alistair J.Manning, Hannah Chawner, Dien Wu, Samuel Hammer.
Funding acquisition: Heather Graven.
Investigation: Giulia Zazzeri.
Methodology: Giulia Zazzeri, Eric Saboya, Liam Blyth, Alistair J. Manning.
Project Administration: Heather Graven.
Supervision: Heather Graven.
Validation: Heather Graven, Xiaomei Xu.
Writing – original draft: Giulia Zazzeri.
Writing – review & editing: GiuliaZazzeri.
Data Availability
The data used for this study include the observations at Imperial College London, radiocarbon measurements and simulated values using the Met Office model NAME. They are in a.csv format and available at the following repository: https://doi.org/10.5281/zenodo.7777987. Data are accessible to the general public without any restrictions. Figures were made with Matplotlib 3.6.0. (https://matplotlib.org/). Maps in the supplementary material were made using Matplotlib with Cartopy (https://pypi.org/project/Cartopy/).
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Additional details
- European Research Council
- 67910
- Accepted
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2023-07-16Manuscript Accepted
- Caltech groups
- Division of Geological and Planetary Sciences
- Publication Status
- Published