Global Groundwater Carbon Mass Flux and the Myth of Atmospheric Weathering
Bibliographic record
Abstract
Abstract Our recent steady‐state mass‐balance modeling suggests that most global carbonic‐acid weathering of silicate rocks occurs in the vadose zone of aquifer systems not on the surface by atmospheric CO 2 . That is, the weathering solute flux is nearly equal to the total global continental riverine carbon flux, signifying little atmospheric weathering by carbonic acid. This finding challenges previous carbon models that utilize silicate weathering as a control of atmospheric CO 2 levels. A robust analysis utilizing global estimates of groundwater carbon concentration generated by a geospatial machine learning algorithm was coupled with recharge flux in a geographic information system environment to yield a total global groundwater carbon flux of between 0.87 and 0.96 Pg C/year to the surface environment. On discharging to the surface, the carbon is speciated between 0.01 and 0.11 Pg C/year as CaCO 3 ; 0.35 and 0.38 Pg C/year as CO 2 gas; and 0.49 and 0.51 Pg C/year as dissolved HCO 3 − . This total weathering carbon flux was calculated for direct ocean discharge (0.030 Pg C/year); endorheic basins (0.046 Pg C/year); cold‐wet exorheic basins (0.058 Pg C/year); warm‐dry exorheic basins (0.072 Pg C/year); cold‐dry exorheic basins (0.115 Pg C/year); and warm‐wet exorheic basins (0.448 Pg C/year).
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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 | 0.000 | 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 | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".