Variations of atmospheric 12CO2 and 13CO2 from the year 1000 to 2024
Abstract
A simple model gives good agreement between observed emissions of CO2 into the atmosphere from the combustion of fossil fuels and observed increases of the atmospheric concentrations C of CO2 and decreases of the isotope delta value delta13C. If fossil fuel emissions were to cease the model predicts that: (1) the difference between the CO2 concentration C and the preindustrial value, Co = 280 ppm, would decay exponentially with time constant of 60 y; (2) the difference between the concentration-delta-value product C x delta13C and the preindustrial value Co x delta13Co = (280 ppm) x (-6.5%%), would decay exponentially with a time constant of 8 y. The decay times are different because of isotopic exchange, largely driven by photosynthesis and respiration on the land.
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BibTeX
@misc{wijngaarden2026variations,
title = {{Variations of atmospheric 12CO2 and 13CO2 from the year 1000 to 2024}},
author = {W. A. van Wijngaarden and W. Happer},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.38063},
eprint = {2609.38063},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.38063},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Variations of atmospheric 12CO2 and 13CO2 from the year 1000 to 2024
AU - W. A. van Wijngaarden
AU - W. Happer
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.38063
UR - https://arxiv.org/abs/2609.38063
AB - A simple model gives good agreement between observed emissions of CO2 into the atmosphere from the combustion of fossil fuels and observed increases of the atmospheric concentrations C of CO2 and decreases of the isotope delta value delta13C. If fossil fuel emissions were to cease the model predicts that: (1) the difference between the CO2 concentration C and the preindustrial value, Co = 280 ppm, would decay exponentially with time constant of 60 y; (2) the difference between the concentration-delta-value product C x delta13C and the preindustrial value Co x delta13Co = (280 ppm) x (-6.5%%), would decay exponentially with a time constant of 8 y. The decay times are different because of isotopic exchange, largely driven by photosynthesis and respiration on the land.
ER -