Methodology

How the edition was made: methods, the model card, the evidence cut and its age, the acceptance record and the glossary.

14 min read0 figures13 tables21 notesNR-SECTOR-CLIMATE-GLOBAL-2026-BASELINE

Contents

A.1Methods

The global baseline uses published values and four simple derivations. Each is shown in full so that any reader can reproduce it.

Table A.1Methods
No.	Derivation	Calculation	Result
(1)	Difference between the two 1.5 °C budgets, from 2026	170 − 130 GtCO2	40 GtCO2
(2)	Difference between the ERA5 and WMO estimates of 2025 warming	1.47 − 1.43 °C	0.04 °C
(3)	Difference between the August 2026 value and the 12-month mean to August, ERA5	1.65 − 1.48 °C	0.17 °C
(4)	Sum of the heat shares: ocean, land, ice and atmosphere	91 + 5 + 3 + 1	100%

Table A.2Coupling strength scale (matrix and model card)
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

Table A.3Status grammar
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, Climate Sector Model v0

Model ID: MDL-GS07-CLIMATE · v0.1
Purpose: represent the global climate system and its couplings to water, food, health and biodiversity
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

5strong

documented within one season

8moderate

documented, buffered

7weak

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-SECTOR-CLIMATE-GLOBAL-2026-B0
Type: baseline documentary cut
Resolution policy: pinned · as of 30 September 2026
Sources pinned: 48 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 climate annual cut

Lineage

01
source edition
02
pinned citation
03
finding
04
page
05
publication record

Table A.4From the baseline cut to the federation cut
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	Climate Sector 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.

Table A.5Evidence age and coverage
Indicator	Observed	Released	Cadence	Next release
Global temperature	2025	Jan 2026, updated 28 Jan 2026	annual	next summary in January 2027
Gas concentrations	2024	Oct 2025	annual	2025 values not bound at the close
Emissions and budget	2024, with 2025 projected	May 2026	annual	next Global Carbon Budget
Human-induced warming	2025	Jun 2026	annual	next indicators update
Ocean heat and sea level	2025	Mar 2026	annual	next State of the Global Climate
Current temperature	Aug 2026	Sep 2026	monthly	monthly
El Niño state	Sep 2026	Sep 2026	monthly	monthly
River discharge	2025	Sep 2026	annual	next water report
Hunger	2025	Jul 2026	annual	next SOFI
Climate finance	2023	Jun 2025	annual	next Global Landscape in 2026

Table A.6Coverage by system at baseline
System	Coverage	Thinnest dimension
Temperature and gases	GOOD	regional detail
Emissions and budget	GOOD	method differences
Ocean and ice	GOOD	values for 2026
Water cycle	PARTIAL	groundwater and regional detail
Health	PARTIAL	global heat deaths on one basis
Food	PARTIAL	climate-attributed share of hunger
Finance	PARTIAL	adaptation flows after 2023
Resilience	THIN	tested capabilities beyond early warning

Table A.7Designed empty states: what is not bound, what would fill it and why
Field	Source that would fill it	Blocker
Global annual temperature for 2026	C3S annual summary and WMO State of the Global Climate for 2026¹²	the year was incomplete at evidence close; the January to August position is cited from the C3S bulletin⁴⁷
Ocean heat content and sea level for 2026	WMO State of the Global Climate for 2026²; annual indicators update⁷	not yet published; annual products appear in 2027
Emissions for 2026	Global Carbon Budget 2026⁶	not yet published; the 2025 value is a projection
Headline values of the UNEP Emissions Gap Report 2025 and 2026 from a primary document	UNEP Emissions Gap Report³⁴⁴⁶	the issuer site refused automated access; only a secondary news item was read³³
Effects of the 2026 El Niño on harvests, rivers and health	FAO, WMO and WHO reports after the event⁴⁸²⁶	the event is under way; SOFI projections omit it
Global heat deaths on one basis	peer-reviewed global heat mortality studies; Lancet Countdown³⁷	the Lancet report was not opened; European estimates are not global
Losses from 2025 and 2026 extremes on one basis	insurers, development banks and national agencies³³⁸	estimates use different definitions; the UNDRR report was not opened
Adaptation finance flows after 2023 and need by region	CPI 2026 landscape; UNEP Adaptation Gap Report²⁰³⁶	the 2026 landscape is not yet issued; the UNEP report was not opened
Public climate finance provided and mobilised, from a primary document	OECD climate finance report⁴⁰	the issuer site refused automated access
Carbon prices and coverage	World Bank carbon pricing report³⁹	the issuer site refused automated access; no figure used
National climate targets in the 2035 round	UNFCCC NDC synthesis report³⁵	the issuer site refused automated access; no figure used
Groundwater storage by region	WMO water report data tables²⁴; national agencies	the full report was not opened; only the key messages were read
Tipping element thresholds with confidence ranges	Global Tipping Points Report full report¹⁶	the full report PDF was not opened; only the key messages were read
Capability rungs beyond early warning	ministries, agencies and operators	not reviewed

A.5Evidence cards, two anchor sources

Issued by the Copernicus Climate Change Service at ECMWF (published January 2026, updated 28 January 2026) from the ERA5 reanalysis. Annual. Role: binds CLI-001 and the sea-ice readings.

EVD-GS07-001

C3S Global Climate Highlights 2025¹

Compiled by the Global Carbon Project and published in a peer-reviewed data journal (May 2026). Annual. Role: binds ENE-004 and CLI-005. The 2025 values are preliminary.

EVD-GS07-002

Global Carbon Budget 2025⁶

Table A.8Quality dimensions at baseline
Dimension	EVD-GS07-001	EVD-GS07-002
Completeness	global coverage from 1940; five other datasets compared	all emission sources and sinks; land-use emissions remain uncertain
Timeliness	about 2 weeks after the year	about 5 months after the year
Revision	figures updated on 28 January 2026	living data update each year
Method transparency	data and methods published	methods and data published
External validation	compared with five other datasets	multiple independent approaches compared

Evidence cards to follow in 2027

WMO²: indicator data tables behind the annual report
Global Carbon Project⁶: regional emissions tables
NOAA⁵: monthly gas series
C3S⁴⁷: the monthly bulletin series for 2026

A.6Publication acceptance record

Editorial self-check at evidence close. Every applicable item carries a disposition; the remaining items are review, approval and deposit.

Table A.9Publication acceptance record
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

Table A.10The status every value carries
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

Table A.11Series terms
Term	Meaning
Baseline Edition	the inaugural annual edition that fixes the reference state for the series
WEFH+B	climate, 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

Table A.12Abbreviations used in this edition
Abbreviation	Expansion
C3S	Copernicus Climate Change Service
CO2	carbon dioxide
EDGAR	Emissions Database for Global Atmospheric Research
ENSO	El Niño-Southern Oscillation
ERA5	fifth-generation ECMWF reanalysis
GtCO2e	gigatonnes of carbon dioxide equivalent
NDC	nationally determined contribution
ppm	parts per million
SDG	Sustainable Development Goal
SOFI	The State of Food Security and Nutrition in the World
WMO	World Meteorological Organization
ZJ	zettajoule

A.10Technical annex

Table A.13Technical 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-GS07-ELN-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 hazard notes	cards for the major monsoon, storm, basin and coastal systems	WITH REGIONAL EDITIONS
A.8	Review statements	pass-by-pass review record	AT RELEASE

A.1 · indicator definition: global surface temperature above the pre-industrial level

Construct: global mean near-surface air temperature relative to the 1850 to 1900 average
Unit: degrees Celsius
Method: reanalysis or merged observation datasets, offset to the 1850 to 1900 level
Source: C3S Global Climate Highlights 2025¹
Uncertainty: datasets differ by about 0.1 °C; WMO gives ±0.13 °C²
Known limits: a single year is not the long-term warming level; the pre-industrial offset is an estimate

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

1Copernicus Climate Change Service (C3S), ECMWF (ed.), Global Climate Highlights 2025 (published 14 January 2026, updated 28 January 2026). ECMWF, Bonn. DOI 10.24381/b3nm-p354. Observation year 2025. Opened in full (PDF). Accessed 2026-11-03. doi:10.24381/b3nm-p354 back
2WMO (ed.), State of the Global Climate 2025 (publication page and press release of 23 March 2026). World Meteorological Organization, Geneva. Observation year 2025. Opened: page and press release; the full report was not opened. Accessed 2026-11-03.back
47Copernicus Climate Change Service (C3S), Surface air temperature for August 2026 (monthly climate bulletin, September 2026; the page shows no publication date, placed in September 2026 from its file path). ECMWF, Bonn. Observation year 2026. Opened: bulletin page. Accessed 2026-11-03.back
7Forster, P.M. et al., Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth System Science Data 18, 3889 to 3933, 2026. DOI 10.5194/essd-18-3889-2026. Observation year 2025. Opened in full (PDF). Accessed 2026-11-03. doi:10.5194/essd-18-3889-2026 back
6Friedlingstein, P. et al., Global Carbon Budget 2025, Earth System Science Data 18, 3211 to 3288, 2026. Global Carbon Project. DOI 10.5194/essd-18-3211-2026. Observation year 2024 (2025 preliminary). Opened in full (PDF). Accessed 2026-11-03. doi:10.5194/essd-18-3211-2026 back
34UNVERIFIED, not opened: UNEP (ed.), Emissions Gap Report 2025: Off Target (November 2025). United Nations Environment Programme, Nairobi. Observation year 2024. The issuer site refused automated access; figures were seen only in search summaries and are not used. Accessed 2026-11-03.back
46UNVERIFIED, not opened: POST-CLOSE, context only: UNEP (ed.), Emissions Gap Report 2026 (released 21 October 2026, after the evidence close). United Nations Environment Programme, Nairobi. Observation year 2026. Not opened; its release is known only from a secondary news item [33] and no figure is taken from it. Accessed 2026-11-03.back
33POST-CLOSE, context only: Potsdam Institute for Climate Impact Research (ed.), Latest News listing, item of 21 October 2026 on the new UNEP Emissions Gap Report. PIK, Potsdam. Observation year 2026. Opened: news listing (a secondary source for the UNEP report). Accessed 2026-11-03.back
48NOAA Climate Prediction Center, ENSO diagnostic discussion of 10 September 2026. National Weather Service, College Park. Observation year 2026. Opened: discussion page. Accessed 2026-11-03.back
26FAO, IFAD, UNICEF, WFP and WHO (eds.), The State of Food Security and Nutrition in the World 2026, joint news release of 21 July 2026 (as published by WHO). Rome. Observation year 2025. Opened: news release; the report was not opened. Accessed 2026-11-03.back
37UNVERIFIED, not opened: Romanello, M. et al., The 2025 report of the Lancet Countdown on health and climate change, The Lancet 406, December 2025. Observation year 2024. Only the bibliographic record was read; the full text was not opened and no figure is taken from it. Accessed 2026-11-03.back
3WMO (ed.), State of the Global Climate 2025, supplement on extreme events and impacts (May 2026). World Meteorological Organization, Geneva. Observation year 2025. Opened in full (PDF). Accessed 2026-11-03.back
38UNVERIFIED, not opened: UNDRR (ed.), Global Assessment Report on Disaster Risk Reduction 2025, special report. United Nations Office for Disaster Risk Reduction, Geneva. Observation year 2025. The issuer site refused automated access; no figure is taken from it. Accessed 2026-11-03.back
20Naran, B. et al., Global Landscape of Climate Finance 2025 (23 June 2025). Climate Policy Initiative, London. Observation year 2023. Opened: publication page with the headline figures; the report was not opened. Accessed 2026-11-03.back
36UNVERIFIED, not opened: UNEP (ed.), Adaptation Gap Report 2025. United Nations Environment Programme, Nairobi. Observation year 2025. The issuer site refused automated access; no figure is taken from it. Accessed 2026-11-03.back
40UNVERIFIED, not opened: OECD (ed.), Climate Finance Provided and Mobilised by Developed Countries in 2013 to 2022. OECD, Paris. Observation year 2022. The issuer site refused automated access; no figure is taken from it. Accessed 2026-11-03.back
39UNVERIFIED, not opened: World Bank (ed.), State and Trends of Carbon Pricing 2025. World Bank, Washington DC. Observation year 2025. The issuer site refused automated access; no figure is taken from it. Accessed 2026-11-03.back
35UNVERIFIED, not opened: UNFCCC secretariat (ed.), Nationally determined contributions synthesis report (2025). Bonn. Observation year 2025. The issuer site refused automated access; no figure is taken from it. Accessed 2026-11-03.back
24WMO (ed.), State of Global Water Resources 2025 (publication page, 17 September 2026). World Meteorological Organization, Geneva. Observation year 2025. Opened: publication page with key messages; the full report was not opened. Accessed 2026-11-03.back
16Global Tipping Points Report 2025 (160 authors, University of Exeter), key messages. Global Tipping Points project, Exeter. Observation year 2025. Opened: project page with key messages; the full report was not opened. Accessed 2026-11-03.back
5POST-CLOSE, context only: Lan, X., Tans, P. and Thoning, K.W., Trends in globally averaged CO2, CH4 and N2O, annual mean data files (version of 9 October 2026). NOAA Global Monitoring Laboratory, Boulder. DOI 10.15138/9N0H-ZH07 (CO2). Observation year 2025. Opened: data files. Accessed 2026-11-03. doi:10.15138/9N0H-ZH07 back

Cite this annex

Valadbaygi, S. (Ed.). (2026). Annex A: Methodology. In Global Climate Risk and Resilience Report 2026: Baseline Edition, The State of the World’s Climate and Earth System. (Baseline Edition 2026, Report No. NR-SECTOR-CLIMATE-GLOBAL-2026-BASELINE) [Draft under review]. The Global Centre for Risk and Innovation (GCRI).

Every citation form of the whole report, BibTeX and RIS included, is on the edition home. Cite this report

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