Correcting an Error in Some Interpretations of Atmospheric 14C Data
Earth Sciences
Volume 9, Issue 4, August 2020, Pages: 126-129
Received: Jul. 5, 2020; Accepted: Aug. 4, 2020; Published: Aug. 13, 2020
Views 62      Downloads 63
Author
David Evans Andrews, Department of Physics and Astronomy, University of Montana, Missoula, USA
Article Tools
Follow on us
Abstract
The variable “∆14C”, commonly used in radiocarbon dating and tracing applications to quantify 14C levels, is a measure of the ratio of the radioisotope 14C to other carbon in a sample. After atmospheric nuclear testing in the 1950’s and 1960’s nearly doubled atmospheric 14C, the later evolution of ∆14C allowed insights into the dynamics of carbon exchange between the atmosphere and terrestrial and marine sinks. But a few authors without backgrounds in isotope measurements have confused ∆14C with excess 14C concentration. They erroneously interpret the present recovery of ∆14C to near its pre bomb test value as evidence that atmospheric 14C concentration has returned to its earlier value. From this they reach further incorrect conclusions about the fate of anthropogenic CO2 introduced into the atmosphere by fossil fuel burning. An estimate of the true time dependence of atmospheric 14C concentration over the past century, calculated from averaged atmospheric ∆14C and CO2 data is presented. The data show that 14C concentrations remain over 30% above 1950 values, and have begun to increase, even as ∆14C continues to fall. This confirms the prediction of a conventional model of the carbon cycle. The unconventional models of carbon dynamics motivated by the mistake, on the other hand, are excluded by the properly interpreted 14C data.
Keywords
Carbon Accumulation, Radiocarbon, Atmospheric CO2
To cite this article
David Evans Andrews, Correcting an Error in Some Interpretations of Atmospheric 14C Data, Earth Sciences. Vol. 9, No. 4, 2020, pp. 126-129. doi: 10.11648/j.earth.20200904.12
Copyright
Copyright © 2020 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
References
[1]
Essenhigh, R. H. (2009). Potential dependence of global warming on the residence time (RT) in the atmosphere of anthropogenically sourced carbon dioxide. Energy & Fuels, 23, 2773−2784.
[2]
Harde, H.(2017). Scrutinizing the carbon cycle and CO2 residence time in the atmosphere. Global and Planetary Change, 152, 19-26.
[3]
Harde, H. (2019). What humans contribute to atmospheric CO2: Comparison of carbon cycle models with observations. Earth Sciences. 8 (3), 139-159. doi: 10.11648/j.earth.20190803.13.
[4]
Berry, E. X. (2019). Human CO2 emissions have little effect on atmospheric CO2. International Journal of Atmospheric and Oceanic Sciences, 3 (1), 13-26. doi: 10.11648/j.ijaos.20190301.13.
[5]
Cawley, G. C. (2011). On the atmospheric residence time of anthropogenically sourced CO2. Energy Fuels 25, 5503–5513, http://dx.doi.org/10.1021/ef200914u.
[6]
Koehler, P., Hauck, J., Volker, C,. Wolf-Gladrow, D. A., Butzin, M, Halpern, J. B. et al.(2017) Comment on “Scrutinizing the carbon cycle and CO2 residence time in the atmosphere by H. Harde”. Global and Planetary Change. 164, 67-71.
[7]
Caldeira, K., Raul, G. H., and Duffy, P. B. (1998). Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content. Geophysical Research Letters, 25 (20), 3811-3814.
[8]
Turnbull, J., Rayne, P., Miller, J., Naegler, T., Ciais, P., Cozic, A. (2009). On the use of 14CO2 as a tracer for fossil fuel CO2: Quantifying uncertainties using an atmospheric transport model., Journal of Geophysical Research, 114, D22302. https://doi.org/10.1029/2009JD012308
[9]
Levin, I. and Hesshaimer, V. (2000). Radiocarbon: A unique tracer of global carbon cycle dynamics., Radiocarbon, 42 (1), 69–80.
[10]
Turnbull, J. C., Mikaloff Fletcher, S. E., Ansell, I., Brailsford, G. W, Moss, R. C., Norris, M. W, et al. (2017). Sixty years of radiocarbon dioxide measurements at Wellington, New Zealand: 1954–2014. Atmos. Chem. Phys., 17, 14771–14784. https://doi.org/10.5194/acp-17-14771-2017.
[11]
Hua, Q., Barbetti, M., Rakowski, A. Z. (2013). Atmospheric radiocarbon for the period 1950–2010. Radiocarbon, 55, pp. 2059–2072. https://doi.org/10.2458/azu_js_rc.v55i2.16177
[12]
Graven, H., Allison, C. E., Etheridge, D. M., Hammer, S., Keeling, R. F., Levin, I., et al. (2017). Compiled records of carbon isotopes in atmospheric CO2 for historical simulations in CMIP6, Geosci. Model Dev., 10, 4405–4417, https://doi.org/10.5194/gmd-10-4405-2017.
[13]
Stenstrom, K. E., Skog, G., Gerogiadou, Genberg. J., Johansson, A. (2011). A guide to radiocarbon units and calculations. Lund University, LUNFD6 (NFFR-3111) /1-17/ (2011). https://www.hic.ch.ntu.edu.tw/AMS/A%20guide%20to%20radiocarbon%20units%20and%20calculations.pdf
[14]
Stuiver, M. and Polach, H.(1977). Discussion: Reporting of 14C data”. Radiocarbon, 19 (3), 355-363. https://journals.uair.arizona.edu/index.php/radiocarbon/article/viewFile/493/498
[15]
World Data Centre for Greenhouse Gasses http://gaw.kishou.go.jp/
[16]
Suess, H. E. (1955), Radiocarbon concentration in modern wood”, Science, 122, 415-417.
ADDRESS
Science Publishing Group
1 Rockefeller Plaza,
10th and 11th Floors,
New York, NY 10020
U.S.A.
Tel: (001)347-983-5186