Stage 15 R2 — anthropocene water-debris feasibility

Status: historical feasibility gate satisfied by a bounded exploration-only experiment; no promotion

Checked: 2026-08-10

Historical contract: contracts/water-debris-evidence-v1.schema.json

Historical source manifest: fixtures/water-debris-evidence/v1/manifest.json Implemented experiment contract: contracts/anthropocene-water-debris-experiment-v1.schema.json Implemented manifest: fixtures/anthropocene-water-debris/v1/manifest.json

Decision

The original “do not implement” decision applied to a proposed merged global debris field. That stop remains valid: the reviewed sources do not establish one redistributable global spatial package with dates, units, uncertainty, and reuse rights across shoreline counts, surface samples, modeled concentration, river emissions, cleanup tracks, and depth profiles.

A narrower implementation gate is now satisfied. Twelve 2025/2026 atlas edition SVGs render only five geolocated North Pacific depth-profile stations observed in 2018. Every other source family remains context-only or UNAVAILABLE; no garbage-patch polygon or invented thickness is drawn. The edition label is not represented as an observation year. All five points pass qualified forward/reverse checks in all six projection layouts.

The standard observation family has separately migrated to anthropocene-particulate-2025 and anthropocene-particulate-2026. The water-debris products remain exploration-only and outside default generation, release, and publication.

Source findings

Source	What it can support	What it cannot establish here
NOAA MDMAP	Dated, protocol-based shoreline macro-debris observations and interactive export	Open-ocean concentration, river emissions, operational tracks, or depth
NOAA 2024 national survey record	CC0 candidate-site geometry and survey-design context	Debris observations or a global layer
The Ocean Cleanup GPGP overview	Evidence vocabulary for samples, modeled concentration, cleanup, and vertical distribution	A checked redistributable coordinate/raster package or reuse license
2015–2022 North Pacific study	Publication-level context for repeated trawl/aerial sampling and modeled change	Authorization to redistribute underlying spatial observations or graphics
North Pacific depth study	CC BY 4.0 station coordinates and observed depth profiles from 2018; five station locations are rendered	A global depth field, patch boundary, or permission to infer depth where it was not observed

NOAA MDMAP remains useful for a later shoreline-observation experiment, but no MDMAP observation export is bundled here. The Ocean Cleanup overview and modeled illustrations support vocabulary and source discovery only; they are not traced into atlas geometry.

Required evidence model

Every future record belongs to exactly one of these classes:

observed shoreline debris;
observed surface sample;
modeled concentration field;
modeled river emission;
recorded cleanup operation; or
observed depth profile.

Each record requires source identity, observation/model time, coordinates and CRS, units, sampling effort or model resolution, uncertainty, access method, license, redistribution decision, and preparation history. A model boundary is not a measured edge. Cleanup location is not concentration. A shoreline count is not an ocean raster. Unknown depth is UNAVAILABLE, never zero.

Implemented bounded gate

The first experiment now satisfies the minimum gate without broadening it:

one CC BY 4.0 depth-profile source supplies five actual coordinates, dates, and maximum sample depths;
depth-profile is the only rendered evidence class;
source periods and North Pacific geographic limits remain visible;
observation, context-only, and unavailable states are distinct;
all five records have qualified forward/reverse fixtures in all six layouts;
the observed layer is capped at 60% opacity and the title uses the doubled scale, without treating opacity as uncertainty; and
the manifest explicitly denies standard lifecycle, default generation, and public release.

The checked contact sheet is output/anthropocene-water-debris-v01/contact-sheet.png. A global garbage-patch surface or depth depiction is still unsupported.

Stop conditions

No website illustration or publication figure becomes source geometry.
No world coverage is inferred from a national or North Pacific study.
No missing observation becomes zero debris.
No surface polygon acquires invented thickness or depth.
No research prototype enters standard or optional generation without a separate reviewed promotion decision.