{
  "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.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.38063",
  "author_total": 2,
  "authors": [
    {
      "name": "W. A. van Wijngaarden"
    },
    {
      "name": "W. Happer"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3xy6pbewsy6r9.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.38063",
  "fulltext_url": null,
  "id": "3xy6pbewsy6r9",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.38063",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.ao-ph"
    ],
    [
      "openalex",
      "2306|Atmospheric and Environmental Gas Dynamics"
    ]
  ],
  "openalex": "W7214959096",
  "pdf_url": "https://arxiv.org/pdf/2609.38063",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-29",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3xy6pbewsy6r9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2609.38063",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.38063"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "arxiv:physics.ao-ph",
      "subfield": "atmospheric"
    }
  ],
  "title": "Variations of atmospheric 12CO2 and 13CO2 from the year 1000 to 2024",
  "title_text": "Variations of atmospheric 12CO2 and 13CO2 from the year 1000 to 2024",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/3xy6pbewsy6r9",
  "venue": "arXiv",
  "versions": []
}