Carbon cycle box modeling studies of the Paleocene-Eocene thermal maximum
Bibliographic record
Abstract
Approximately 55 million years ago, an unprecedented amount of light carbon was abruptly released into the ocean and atmosphere. This event, known as the Paleocene-Eocene thermal maximum (PETM), is documented by large negative carbon isotope excursions in marine and soil carbonates and by global environmental changes. Models have been applied to constrain the amount of carbon released during the PETM. In this study, the Walker-Kasting carbon cycle box model is revisited and, after correcting its carbon isotope equations, it is used to resolve a discrepancy in previous emission estimates. In addition, the atmospheric methane box model of Schmidt-Shindell is coupled to the Walker-Kasting model to explore the role of methane during the PETM. This coupled model is then combined with results from other modeling studies to demonstrate that the PETM may have been caused by the rel ease of approximately 3500 Pg C of thermogenic methane into the Atlantic Ocean.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".