Rates and patterns of permafrost thaw induced landcover change at Scotty Creek, Canada
Bibliographic record
Abstract
In the peatland-dominated regions of discontinuous permafrost in northwestern Canada, permafrost thaw is altering landscapes at rates without precedent in the historical record. The present study uses a combination of remote sensing and ground based methods to examine the rates and patterns of permafrost thaw and how such thaw is changing the form and function of the landscape. The area within a 4 km2 area of interest underlain by permafrost decreased from 51% in 1977 to 43% in 2010, and to 40% in 2018, indicating an increase in the permafrost thaw rate from 0.24% yr-1 between 1977 and 2010, and 0.43% yr-1 between 2010 and 2018. Between 1977 and 2018, the permafrost-free terrain expanded by a factor of 1.25. The average expansion of all individual wetlands over the same period ranged between 0.30 and 1.33. The total permafrost terrain contracted by a factor of 0.8 between 1977 and 2018, while estimates of the average shrinkage factor of all individual plateaus ranged between 0.54 and 0.79. Wetland coalescence and plateau fragmentation processes complicated the computation of the average expansion and contraction factors. Measurements made along transects since 2011 indicated a persistent lowering of the permafrost table (vertical thaw), simultaneous recession of plateau edges (horizontal thaw), widespread development of talik, and preferential permafrost thaw driven by local site factors. Between 2011 and 2021, the average thaw below transects varied from 2.8 to 12.3 cm yr-1. The transect measurements also indicated that as the width of plateaus decreased due to thaw, the average rate of thaw increased. Geophysical measurements below an intensively studied plateau indicated that it lost 13% of its permafrost volume between 2010 and 2019. This thaw was equally driven by horizontal displacement of the plateau edge and by upward-displacement of the base of permafrost. The downward-directed thaw as indicated by the displacement of the permafrost table accounted for a slightly lower fraction.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 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".