Methodology
How the edition was made: methods, the model card, the evidence cut and its age, the acceptance record and the glossary.
Contents
- ·Edition home
- ·Executive summary
- 1Shared spaces change together
- 2Key findings
- 3Systems and sectors at baseline
- 4Risks and capability
- 5High seas treaty implementation and the first protected areas
- 6Readings from the other desks
- 7The 2027 agenda
- 8Systems in depth
- AMethodology
- BData appendix
- CReferences and record
- ·Complete edition, for print
A.1Methods
The global baseline uses published values and four simple derivations. Each is shown in full so that any reader can reproduce it.
| No. | Derivation | Calculation | Result |
|---|---|---|---|
| (1) | Arctic Greenland loss in 2025 below the 2003 to 2024 average | 219 − 129 | 90 billion tons |
| (2) | Ratio of sea level rate, 2016 to 2025 against 1993 to 2002 | 4.1 ÷ 2.1 | ≈ 1.95 |
| (3) | Share of assessed stocks that are not sustainable | 100 − 62.4 | 37.6% |
| (4) | Share of the high seas outside protected areas | 100 − 1.45 | 98.55% |
| Strength | Definition |
|---|---|
| STRONG | a disruption in the source system has historically changed the target system’s service or output within one season, in more than one region |
| MODERATE | an effect is documented but buffered or slower |
| WEAK | an effect is plausible but not documented at global scale |
| Label | Rule |
|---|---|
| Reported | value as issued by its source, with year |
| Inferred | reasoned from cited evidence; never a measurement |
| Estimated | Nexus analytical value with stated method |
| Scenario | conditional on stated assumptions |
| Expert input | structured editorial judgement awaiting evidence |
A.2Model card, Global Commons Model v0
- Model ID
- MDL-SR12-COMMONS · v0.1
- Purpose
- represent the ocean, the poles, the high seas and orbit as linked shared spaces and the mechanisms by which change spreads between climate, biodiversity, food, minerals and trade
- Family
- graph-based system of systems
- Inputs
- the cited sources of this edition; no proprietary data
- Method
- expert-specified coupling strengths (STRONG · MODERATE · WEAK) from assessments and analogue events
- Validation
- none yet, first validation against federation evidence in 2027
- Uncertainty
- qualitative; strengths are hypotheses, not measurements
- Domain of validity
- global scale; not for asset-, site- or country-level use
- Reproducibility
- strength table and sources published in this edition
20couplings
typed in v0
3strong
documented within one season
6moderate
documented, buffered
11weak
plausible, undocumented
A.3The baseline evidence cut
Every Nexus edition is published from a frozen evidence cut. The global baseline cut is documentary: it pins the exact edition of every source cited. Federation cuts begin with the first national Foundry cuts in 2027.
- Cut ID
- DC-STRATEGIC-COMMONS-GLOBAL-2026-B0
- Type
- baseline documentary cut
- Resolution policy
- pinned · as of 30 September 2026
- Sources pinned
- 42 cited sources, each at the edition and access date in the references
- Model runs
- none at baseline, analytical values are stated with their method
- Digest
- computed at freeze and recorded in the publication record
- Supersedes
- nothing, first cut of the series
- Superseded by
- the 2027 ocean and polar commons annual cut
Lineage
- 01
source edition
- 02
pinned citation
- 03
finding
- 04
page
- 05
publication record
| Element | Baseline 2026 | 2027 global annual |
|---|---|---|
| Sources | cited global publications, pinned by edition | national, regional and sector cuts through one graph |
| Analysis | stated methods and editorial estimates | typed analysis specifications |
| Models | Global Commons Model v0 specification | model runs with receipts |
| Findings | twelve baseline findings | findings re-bound to federation evidence |
| Review | five passes scheduled | five passes on the exact digest |
A.4Evidence age and coverage
A 2026 global edition rests on evidence observed in many different years. This page shows each time base, so that no single year label hides older evidence.
| Indicator | Observed | Released | Cadence | Next release |
|---|---|---|---|---|
| Arctic sea ice minimum | 2025 | Sep 2025 | annual | Sep 2026 analysis |
| Arctic annual review | Oct 2024 to Sep 2025 | Dec 2025 | annual | next Arctic Report Card |
| Sea level rate | 1993 to 2025 | Nov 2025 | annual | next WMO report |
| Reef thresholds | 2025 | Oct 2025 | periodic | no schedule found |
| Planetary boundaries | 2025 | Sep 2025 | annual | next Planetary Health Check |
| Fish stocks | 2023 to 2024 | Jun 2026 | two-yearly | SOFIA 2028 |
| High seas treaty status | 2026 | at reading | per event | next ratification |
| Fisheries subsidies | 2026 | Jul 2026 | per event | next acceptance |
| Seabed licensing | 2026 | Aug 2026 | per event | NOAA decision |
| Orbit | to Dec 2025 | Sep 2026 | annual | ESA 2027 |
| System | Coverage | Thinnest dimension |
|---|---|---|
| Sea ice and ice sheets | GOOD | ice thickness and volume |
| Sea level and heat | GOOD | regional rates |
| Reefs and acidification | PARTIAL | regional reef status |
| Fish | PARTIAL | stock detail by region |
| High seas governance | PARTIAL | effective protection |
| Seabed | THIN | ecosystem baselines |
| Shipping and trade rules | PARTIAL | compliance data |
| Orbit | PARTIAL | debris counts |
| Field | Source that would fill it | Blocker |
|---|---|---|
| Ocean heat content in physical units for 2025 | WMO State of the Global Climate 2025 and ocean data centres | the WMO page read gave a qualitative statement only; the full report was not opened |
| Share of the ocean under effective protection | Protected Planet16 | the page read gave the high seas share only; the overall ocean share field was blank |
| FAO stock status from the report itself | FAO State of World Fisheries and Aquaculture 202622 | the FAO pages returned no figures; values come from a summary page |
| Arctic sea ice winter maximum value for 2025 from the primary page | NSIDC analysis of March 20251 | the analysis page returned an error; the rank is from the NOAA report card |
| Arctic and Antarctic ice thickness and volume | satellite altimetry and ice charts | not retrieved |
| Number of states party to the UN Convention on the Law of the Sea | UN Treaty Collection23 | the status page returned no data |
| Holdings of the ICJ and ITLOS advisory opinions | the full opinions1920 | the pages listed the documents; the opinions were not read |
| Outcome of the July 2026 ISA Council on exploitation rules | ISA Council decisions15 | the page listed decision titles; their text was not read |
| Global temperature and sea surface temperature for 2025 | Copernicus Global Climate Highlights 2025 | the report PDF could not be read |
| Count of tracked objects and fragmentation events in orbit | ESA Space Environment Report 202617 | the page gave no totals; secondary snapshots differ |
| Arctic shipping and seabed activity counts | Arctic Council working groups and national authorities | not retrieved |
| Capability rungs beyond treaty status | states, secretariats and agencies | not reviewed |
A.5Evidence cards, two anchor sources
Issued by the US National Oceanic and Atmospheric Administration. Annual. Role: binds CLI-002 and CLI-003. Coverage: the Arctic, October 2024 to September 2025. The summary page was read; the full report was not opened.
EVD-SR12-001
NOAA Arctic Report Card 20253
Issued by the depositary of the treaty. Per event. Role: binds POL-008. Coverage: global. The status page was read at the time of reading and the party count changes with each ratification.
EVD-SR12-002
UN Treaty Collection record of the high seas treaty11
| Dimension | EVD-SR12-001 | EVD-SR12-002 |
|---|---|---|
| Completeness | regional series; summary page only | status at one date |
| Timeliness | about 2 months after the period | current on the day read |
| Revision | annual update | changes with each deposit |
| Method transparency | chapter authors named in the report | treaty text and article stated |
| External validation | peer review of chapters | depositary record |
Evidence cards to follow in 2027
A.6Publication acceptance record
Editorial self-check at evidence close. Every applicable item carries a disposition; the remaining items are review, approval and deposit.
| Group | Area | Items | Pass | N/A | Pending |
|---|---|---|---|---|---|
| D1 | Identity and scope | 8 | 8 | 0 | 0 |
| D2 | Source and data | 12 | 9 | 1 | 2 |
| D3 | Analysis and models | 12 | 3 | 8 | 1 |
| D4 | Findings and claims | 9 | 8 | 0 | 1 |
| D5 | Figures, tables, maps | 10 | 6 | 2 | 2 |
| D6 | Editorial and citations | 10 | 8 | 0 | 2 |
| D7 | Review and approval | 13 | 0 | 0 | 13 |
| D8 | Artefact and design | 12 | 7 | 0 | 5 |
| D9 | Registry and release | 9 | 0 | 0 | 9 |
Publication gate
- Conditions met
- 14 of 23 at evidence close
- Blocking problems
- none recorded
- Open conditions
- reviews, approval of the exact digest, deposit, registry pointer
Not applicable at baseline
- Model runs
- first runs in Q1 2027
- Maps
- plates in Q2 2027
- Waivers
- none
A.7Status words
| Status | What it means |
|---|---|
| Observed | Measured directly and published by the source. |
| Reported | Published statistics of an official or institutional source. |
| Declared | Stated by the body concerned; not independently measured. |
| Estimated | A Nexus estimate from cited evidence, with its method in Annex A. |
| Modelled | Produced by a stated model from cited inputs. |
| Inferred | Reasoned from cited evidence; not measured. |
| Forecast | A projection by the cited source. |
| Simulated | A simulation result under stated assumptions. |
| Scenario | A conditional statement under stated assumptions; never a prediction. |
| Expert input | Expert judgement, recorded with its basis. |
| Candidate | Proposed for a later edition; not yet evidence. |
| Evidence-quality levels (EQL 1 to 5) grade the source behind a value; they are not a score of the subject. | |
A.8How the edition is made, released and corrected
Every edition is built from a sealed evidence cut, reviewed under three keys, signed and deposited before any site shows it as published; corrections go to Nexus Standards as change proposals and feed the next cut.
| Step | What happens | Source |
|---|---|---|
| 01 Evidence arrives from the pillars | Foundry seals observations and indicator series, Universe hands over after-action and scenario findings, and contributions are screened at every gateway, including this site’s. | |
| 02 The cut is sealed | On the cut date the evidence is pinned under one identifier, so anyone can rebuild the edition from exactly what it was built on. | |
| 03 The edition is assembled | The edition is drafted from its template and content pack. Agents may draft; they never publish and never decide. | |
| 04 The keys turn | At the publisher of record the truth key comes first: every value is checked against its source or stated method before the meaning and capital keys turn. No edition moves on until every key has been turned by a named steward. | |
| 05 The gate opens | A named approver releases one exact digest of the edition; any change after this point is a new version, never a silent edit. | |
| 06 Signed and deposited | The PDF, the web edition and the data bundle are signed together with a manifest and an RO-Crate description, and deposited on Zenodo with a concept and a version DOI. | |
| 07 Published on its desk’s site | Only then does the edition show as published on its desk’s Reports site, and the Collection lists it as a part. | |
| 08 Corrections go to Standards | Method and correction findings go to Nexus Standards as change proposals; citations, corrections and new contributions feed the next evidence cut. |
A teaching model of the process, not a forecast and not a record of any run; dates and counts on this page come from the programme record. Sources: Reports governance at GCRI Canada (2026); Zenodo, repository of record for Reports deposits (2026).
Lifecycle, one state at a time: Draft, Computed, Evidence bound, Reviewed, Approved for release, Published, Corrected, Superseded. This edition is a draft.
A.9Glossary and abbreviations
| Term | Meaning |
|---|---|
| Baseline Edition | the inaugural annual edition that fixes the reference state for the series |
| WEFH+B | water, energy, food, health and biodiversity, the national nexus core |
| Coupling | a typed dependency through which one system transmits to another |
| Protection gap | the share of losses not covered by insurance |
| Capability ladder | LISTED → EXISTS → ADEQUATE → TESTED → DEMONSTRATED |
| EQL | evidence-quality level, 1–5 |
| Evidence cut | a frozen resolution of exact sources and versions |
| NNC · NLC · NWG | National Nexus Consortium · National Leadership Council · National Working Groups |
| Abbreviation | Expansion |
|---|---|
| ABNJ | areas beyond national jurisdiction |
| BBNJ | biodiversity beyond national jurisdiction |
| ESA | European Space Agency |
| FAO | Food and Agriculture Organization |
| IMO | International Maritime Organization |
| ISA | International Seabed Authority |
| ITLOS | International Tribunal for the Law of the Sea |
| NOAA | US National Oceanic and Atmospheric Administration |
| NSIDC | US National Snow and Ice Data Center |
| USNIC | US National Ice Center |
| WMO | World Meteorological Organization |
| WTO | World Trade Organization |
A.10Technical annex
| Item | Annex | Contents | Status |
|---|---|---|---|
| A.1 | Indicator definitions | the global indicator set, with units and sources | IN THIS EDITION |
| A.2 | Coupling strengths | the twenty-cell matrix and its rationale | IN THIS EDITION |
| A.3 | Scenario specification | SCN-SR12-HSP-01 assumptions and signposts | IN THIS EDITION |
| A.4 | Capability placements | rung evidence for fifteen functions | IN THIS EDITION |
| A.5 | Model diagnostics | first runs and validation | 2027 |
| A.6 | Sensitivity analyses | influence of coupling strengths | 2027 |
| A.7 | Regional notes | regional commons cards | WITH REGIONAL EDITIONS |
| A.8 | Review statements | pass-by-pass review record | AT RELEASE |
A.1 · indicator definition: sea ice extent
- Construct
- the area of ocean with at least a set share of ice cover
- Unit
- million square kilometres
- Method
- passive microwave concentration data at 25 km, or analyst-interpreted imagery at 1 km
- Source
- NSIDC and USNIC analyses12
- Uncertainty
- products differ in threshold, resolution and averaging window
- Known limits
- extent does not measure ice thickness or volume
Notes
Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references
- 16UNEP-WCMC and IUCN (eds.), Protected Planet, marine protected areas page (areas beyond national jurisdiction 61% of the ocean; 1.45% covered by protected areas and other effective area-based measures). UNEP-WCMC, Cambridge. Observation year 2026. Accessed 2026-11-03.back
- 22UNVERIFIED, not opened: FAO (ed.), The State of World Fisheries and Aquaculture 2026, doi 10.4060/cd8357en (release 16 June 2026), figures taken from the summary page in [21]; the FAO pages read returned no figures. Food and Agriculture Organization, Rome. Observation year 2024. Accessed 2026-11-03. doi:10.4060/cd8357enback
- 1NSIDC (ed.), Arctic sea ice has likely reached its minimum extent for 2025 (Sea Ice Today analysis, relayed by CIRES; minimum 4.60 million km² on 10 September 2025; tenth lowest in the 47-year record). National Snow and Ice Data Center, Boulder. Observation year 2025. Accessed 2026-11-03.back
- 23UNVERIFIED, not opened: United Nations Convention on the Law of the Sea (1982), cited from memory; the UN status page returned no data. United Nations, New York. Observation year 1982. Accessed 2026-11-03.back
- 19International Court of Justice (ed.), Obligations of States in respect of Climate Change, advisory opinion of 23 July 2025 (case page; documents listed; holdings not read). ICJ, The Hague. Observation year 2025. Accessed 2026-11-03.back
- 20International Tribunal for the Law of the Sea (ed.), Request for an advisory opinion submitted by the Commission of Small Island States on Climate Change and International Law, Case No. 31, advisory opinion of 21 May 2024 (case page; unanimous; holdings not read). ITLOS, Hamburg. Observation year 2024. Accessed 2026-11-03.back
- 15International Seabed Authority (ed.), 31st Session 2026 (session page; Council part I 9 to 19 March 2026 and part II 13 to 24 July 2026; decision titles on exploitation rules and contract extensions; decision texts not read). ISA, Kingston. Observation year 2026. Accessed 2026-11-03.back
- 17European Space Agency (ed.), ESA Space Environment Report 2026 (report page of 14 September 2026; data to end 2025; health index from about 4 to about 50; more than 300 launches and over 4,000 payloads in 2025). ESA, Darmstadt. Observation year 2025. Accessed 2026-11-03.back
- 3NOAA (ed.), Arctic Report Card 2025 (summary page; air temperature, sea ice, precipitation and Greenland ice sheet findings). National Oceanic and Atmospheric Administration, Silver Spring. Observation year 2025. Accessed 2026-11-03.back
- 11United Nations (ed.), Agreement under the UN Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction (status page, UN Treaty Collection; entry into force 17 January 2026; 145 signatories and 105 parties as shown on the page when read). United Nations, New York. Observation year 2026. Accessed 2026-11-03.back
- 2US National Ice Center (ed.), Arctic Sea Ice at Minimum and Maximum Extents, 2025 to 2026 (press release; USNIC 3-day minimum 4.86 million km² in September 2025; 2026 maximum 14.53 million km² on 6 to 8 March by USNIC and 14.29 million km² on 15 March by NSIDC). US National Ice Center, Suitland. Observation year 2026. Accessed 2026-11-03.back