amoc-utac

GenesisAeon Package 18 — Atlantic Meridional Overturning Circulation as UTAC System

AMOC modelled as UTAC dynamical system with physics-based early-warning from van Westen et al. (2024).

Key result: Γ_AMOC ≈ 0.251 (medium-CREP). Neural criticality (Package 20) lands at the same Γ because it shares the same η = 50 % and σ = 2.2 calibration inputs — a shared comparison coordinate, not evidence of shared physics between the two domains.

Installation

pip install amoc-utac

For development:

pip install -e ".[dev]"

Quickstart

amoc-utac run --duration 120
amoc-utac tipping-estimate
amoc-utac zenodo-export

Integration in genesis-os

from genesis_os import GenesisOS
os = GenesisOS()
amoc = os.load_package(18)
results = amoc.run_cycle(duration_years=120)

Benchmark

Validated against RAPID array, van Westen 2024 & Ditlevsen 2023.

Falsifiable Prediction

AMOC crosses 50 % weakening (H* = 0.5 K) between 2045–2065.

Scientific Context — Consensus vs. Single Studies (added 2026-08-01, corrected 2026-08-02)

The Ditlevsen & Ditlevsen (2023) tipping-year estimate this package compares against is a real, published, but more alarmist single study, not the mainstream consensus. Important: the paper was itself corrected in 2025 (Author Correction, Nat. Commun. 16, 7794, DOI 10.1038/s41467-025-63201-y) — the central estimate moved from 2057 [2025-2095] to 2065 [2037-2109]; this package now uses the corrected values. A 2026 preprint (Morr et al., arXiv:2604.20341, not yet peer-reviewed) further argues the underlying statistical fingerprint/model choice is fragile enough that alternative, equally-defensible specifications push the estimate much later.

The IPCC AR6 Working Group I Summary for Policymakers (2021, Section C.3.4) states: "there is medium confidence that the Atlantic Meridional Overturning Circulation will not collapse abruptly before 2100." Note this is not the same as the commonly-repeated shorthand "very unlikely before 2100" — "very likely" in the same AR6 passage describes the assessed weakening itself (24% [4-46%] under SSP1-2.6, 39% [17-55%] under SSP5-8.5 by 2100), not an exclusion of collapse, and "medium confidence" is not a numeric probability. Both the corrected Ditlevsen estimate and the AR6 consensus position are surfaced together in predict_tipping_year()'s return value (ipcc_ar6_confidence_statement, ipcc_ar6_citation, consensus_note) and in the tipping-estimate CLI command's output table, so users see the consensus baseline alongside this package's own (more alarmist) UTAC estimate rather than only the latter.

Global Trajectory Context (added 2026-09-02)

UNEP's "Limiting Overshoot: Navigating Exceedance of 1.5°C and Pathways Towards Return" (UNEP, published 2026-09-02, DOI: 10.59117/20.500.11822/49857) assesses that current policies put the world on track for ~2.6°C warming by 2100, with permanent exceedance of the 1.5°C Paris threshold expected within the next few years (2024 was already ~1.6°C above pre-industrial levels, per Copernicus/C3S). The report's central pathway is "overshoot, peak, and decline": exceed 1.5°C, then attempt to bring temperatures back down via large-scale carbon dioxide removal.

What this does and does not change here: this package's own results (Γ_AMOC ≈ 0.251, the corrected Ditlevsen tipping-year estimate, the AR6 SSP1-2.6/SSP5-8.5 weakening ranges) are not altered by this report — UNEP does not publish an AMOC-specific estimate. What it does provide is current, authoritative context for which emissions scenario is realistic: a ~2.6°C-by-2100 trajectory sits closer to the SSP5-8.5 end of the AR6_WEAKENING_SSP585_PCT range in constants.py than to SSP1-2.6, which is worth keeping in mind when interpreting this package's output against the AR6 consensus band.

Role in the GenesisAeon Ecosystem

amoc-utac is P18 in the GenesisAeon ecosystem, covering the oceanography / AMOC tipping domain. It applies the UTAC-Logistic ODE and CREP metrics to the Atlantic Meridional Overturning Circulation, sharing its criticality framework (Γ ≈ 0.251) with sibling packages across other domains (e.g. neuroscience, heliophysics).

Citation

License

Code: MIT • Docs & Data: CC BY 4.0