Middle Eocene CO<sub>2</sub>and climate reconstructed from the sediment fill of a subarctic kimberlite maar
Bibliographic record
Abstract
Eocene paleoclimate reconstructions are rarely accompanied by parallel estimates of CO 2 from the same locality, complicating assessment of the equilibrium climate response to elevated CO 2 .We reconstruct temperature, precipitation, and CO 2 from latest middle Eocene (ca.38 Ma) terrestrial sediments in the posteruptive sediment fill of the Giraffe kimberlite in subarctic Canada.Mutual climatic range and oxygen isotope analyses of botanical fossils reveal a humidtemperate forest ecosystem with mean annual temperatures (MATs) more than 17 C warmer than present and mean annual precipitation ~4 present.Metasequoia stomatal indices and gas-exchange modeling produce median CO 2 concentrations of ~630 and ~430 ppm, respectively, with a combined median estimate of ~490 ppm.Reconstructed MATs are more than 6 C warmer than those produced by Eocene climate models forced at 560 ppm CO 2 .Estimates of regional climate sensitivity, expressed as MAT per CO 2 doubling above preindustrial levels, converge on a value of ~13 C, underscoring the capacity for exceptional polar amplification of warming and hydrological intensification under modest CO 2 concentrations once both fast and slow feedbacks become expressed.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".