10 · Termination Is a Melt Threshold — tested
Supplied working report; original verdicts not validated.
Review status: Needs review. This is an archival source note, not a passed proof.
report.md
# 10 · Termination Is a Melt Threshold — tested **Source:** Incoprea Theory, Volume XXVI, Theory 75 (glacial-termination-deglaciation). **Claim (verbatim):** "Deglaciation runs to completion once the ratio of melt to accumulation exceeds one by enough to survive a full year, so the end is abrupt." **Prediction:** "Termination should be faster than onset." **Refutation:** "Symmetric onset and termination would remove the feedback." ## Why probable The Pleistocene sawtooth — slow glacial build, fast collapse — is among the most robust features of the δ18O record, and albedo/elevation feedbacks are the standard explanation. ## Method Analysis of the public LR04 benthic δ18O stack (Lisiecki & Raymo 2005, NOAA paleo data, 701 points 0–800 ka; code/termination_test.py). Glacial maxima (>4.4‰, >50 kyr apart) define eight full glacial cycles; each cycle's termination is the drop from the glacial maximum to the following interglacial minimum, and the onset is the rise from the preceding interglacial minimum to that maximum. ## Results | cycle (max ka) | termination rate (‰/kyr) | termination duration (kyr) | onset duration (kyr) | |---|---|---|---| | 19 (last glacial) | 0.113 | 15.0 | 104.9 | | 139 | 0.113 | 15.3 | 99.7 | | 252 | 0.082 | 13.5 | 75.4 | | 342 | 0.111 | 14.4 | 61.9 | | 433 | 0.066 | 28.8 | 57.4 | | 548 | 0.017 | 57.6 | 28.3 | | 631 | 0.030 | 54.3 | 66.0 | | 718 | 0.054 | 21.8 | — | - Median termination rate **0.074 ‰/kyr vs 0.023 ‰/kyr for onset — 3.2× faster**; median duration 18.6 kyr vs 66.0 kyr. - Mann–Whitney U = 49, **p = 0.007** (terminations faster than onsets). - The asymmetry is strong for the well-resolved recent cycles (Terminations I and II: ~15 kyr vs ~100 kyr build-up) and weaker/absent in the older, less-well-resolved cycles — the "abrupt end" is the rule, not universal. ## Verdict **SUPPORTED.** Terminations are systematically faster than onsets (3.2× median rate, p = 0.007), consistent with self-amplifying melt feedbacks; the symmetry refutation is rejected for the ensemble. ## Limitations - δ18O is an ice-volume/proxy mix, not melt rate itself; deep-sea δ18O lags ice volume. - Older cycles are lower-amplitude/noisier; two cycles (548, 631 ka) show weak or reversed asymmetry. Working report — not peer reviewed. Educational information, not medical advice. AI-assisted test: DeepSeek.