The Intergovernmental Panel on Climate Change (IPCC)
Established in 1988 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP), the IPCC is the United Nations body tasked with assessing the science related to climate change.
The IPCC does not conduct its own research. Instead, thousands of scientists from across the globe volunteer as authors to assess the thousands of scientific papers published each year. They provide a comprehensive summary of what is known about the drivers of climate change, its impacts and future risks, and how adaptation and mitigation can reduce those risks.
The assessments are written through three specialized Working Groups:
- Working Group I (WGI): The Physical Science Basis.
- Working Group II (WGII): Impacts, Adaptation, and Vulnerability.
- Working Group III (WGIII): Mitigation of Climate Change.
⚖️ How IPCC Statements Are Weighted for Confidence & Likelihood
The IPCC uses a formal, standardized Calibrated Uncertainty Guidance Framework (Mastrandrea et al., 2010) to evaluate every scientific statement. Authors weight statements across two distinct metrics:
1. Qualitative Confidence Metric
Based on the synthesis of Evidence (type, amount, quality, and consistency of data/models) and Agreement (degree of scientific consensus). Expressed in 5 levels:
• Very Low | Low | Medium | High | Very High Confidence
2. Quantitative Likelihood Metric
Expressed as mathematical probabilities derived from statistical sampling, observations, and CMIP climate model ensembles:
• Unequivocal: 100% (Factual certainty, AR6)
• Virtually Certain: 99–100% probability
• Extremely Likely: 95–100% probability (AR5)
• Very Likely: 90–100% probability (AR4)
• Likely: 66–100% probability (TAR)
• More Likely Than Not: >50–100% (SAR)
🎵 Sonification Engine Mapping: In our application, as the weighted probability moves from Not Likely (~30% in 1990) up to Extremely Likely (>95%) and Unequivocal (100% in 2021), the audio engine transitions harmonically from tense, dissonant tritones into resolved major triads and cathedral unison chords.
1. Main Timeline Dataset (1990 – 2026)
This table summarizes the core metrics across the major IPCC Assessment Reports and Special Reports in chronological order.
| Year | Milestone / Report | Attribution Certainty / Key Statement | Certainty | Consensus % | Treaty support | Musical Key & Chord | Core Authors / Countries | Citations | Pages | Review Comments |
|---|---|---|---|---|---|---|---|---|---|---|
| 1990 | FAR | "Unequivocal detection of enhanced greenhouse effect is not likely for a decade or more." | ~30% | ~50% | 0 (UNFCCC not opened) | A Locrian Dissonant (A3, D♯4, A♯3) | 97 / 20 countries | ~2,315 | ~1,000 | N/A |
| 1992 | UNFCCC | Earth Summit opens United Nations Framework Convention on Climate Change. | N/A | N/A | 154 (Signatories) | D Minor (A3, D4, F4) | N/A | N/A | 26 | N/A |
| 1995 | SAR | "The balance of evidence suggests a discernible human influence on global climate." | ~50% | ~60% | 118 (UNFCCC in force) | F Major (A3, C4, F4) | ~476 / ~40+ countries | ~10,000 | ~1,900 | Not centralized |
| 1997 | Kyoto | Adoption of the Kyoto Protocol targeting emissions cuts for industrialised nations. | N/A | N/A | 84 (Signatories) | A Minor 7th (A3, C4, E4, G4) | N/A | N/A | 24 | N/A |
| 2000 | SRES | Special Report on Emissions Scenarios: Developed four baseline scenarios for greenhouse gas projections. | N/A | N/A | 180 (UNFCCC parties) | D Minor 7th (A3, C4, D4, F4) | Nakicenovic et al. | ~3,000 | 599 | Not centralized |
| 2001 | TAR | "Most of the warming observed over the last 50 years is attributable to human activities." | >66% | ~75% | 186 (UNFCCC parties) | A Sus4 Modal (A3, D4, E4) | ~470 / ~100 countries | ~15,000 | ~2,600 | Not centralized |
| 2004 | Oreskes | Naomi Oreskes publishes first formal consensus study of 928 peer-reviewed abstracts. | N/A | 100% (No rejections) | 190 (UNFCCC parties) | A Modal (A3, D4, E4) | N/A | 928 abs | 2 | N/A |
| 2005 | Kyoto In Force | Kyoto Protocol officially enters into force after Russia's critical ratification. | N/A | N/A | 156 (Kyoto parties) | A Minor (A3, C4, E4) | N/A | N/A | N/A | N/A |
| 2005 | SRCCS | Special Report on Carbon Dioxide Capture and Storage: Assessed CCS potential for emissions reduction. | N/A | N/A | 156 (Kyoto parties) | A7 Sus4 (A3, D4, E4, G4) | ~100 / 30 countries | ~5,000 | 442 | Not centralized |
| 2007 | AR4 | "Most of observed warming since mid-20th century is very likely due to anthropogenic greenhouse gases." | >90% | ~90% | 192 (UNFCCC parties) | A Major 6th (A3, C♯4, E4, F♯4) | >450 / 130+ countries | ~30,000 | ~3,000 | ~90,000+ |
| 2011 | SRREN | Special Report on Renewable Energy Sources: Analysed energy potential to mitigate climate change. | N/A | N/A | 195 (UNFCCC parties) | A Major Triad (A3, C♯4, E4, A4) | 147 / 25 countries | ~5,000 | 1,075 | Not centralized |
| 2012 | SREX | Special Report on Managing Risks of Extreme Events: Linked climate change directly to increased heatwaves. | High conf. | N/A | 195 (UNFCCC parties) | A Major Add9 (A3, C♯4, E4, A4, B4) | 220 / 62 countries | ~6,000 | 582 | Not centralized |
| 2013 | AR5 | "It is extremely likely that human influence has been the dominant cause of the observed warming." | >95% | 97.1% | 195 (UNFCCC parties) | A Major Extended (A3, C♯4, E4, A4, C♯5) | 829 / 80+ countries | ~31,000 | ~4,800 | 143,484 |
| 2015 | Paris | Adoption of the historic Paris Agreement to limit warming to well below 2.0°C. | N/A | N/A | 195 (Signatories) | A Major Soaring Ascending (A3, C♯4, E4, A4, C♯5, E5, A5) | N/A | N/A | 25 | N/A |
| 2016 | Paris In Force | Paris Agreement rapidly achieves emissions and party thresholds, entering into force. | N/A | N/A | 110 (Paris ratifications) | A Major (A2, A3, C♯4, E4) | N/A | N/A | N/A | N/A |
| 2018 | SR15 | Special Report on Global Warming of 1.5°C: Projected severe risks of 2.0°C warming vs 1.5°C. | Very High | N/A | 184 (Paris parties) | A Major 7th High B5 (A3, C♯4, E4, A4, C♯5, E5, A5, B5) | 91 / 40 countries | 6,000+ | 630 | 42,001 |
| 2019 | SRCCL | Special Report on Climate Change and Land: Highlighted degradation and vulnerability of food supply. | High conf. | N/A | 187 (Paris parties) | A Mixolydian High C6 (A3, C♯4, E4, A4, C♯5, E5, A5, C6) | 107 / 52 countries | 7,000+ | 864 | 28,275 |
| 2019 | SROCC | Special Report on Ocean and Cryosphere: Warned of accelerated sea level rise and melting ice sheets. | Very High | N/A | 187 (Paris parties) | A Mixolydian High D6 (A3, C♯4, E4, A4, C♯5, E5, A5, D6) | 104 / 36 countries | 6,981+ | 755 | 31,176 |
| 2021 | AR6 | "It is unequivocal that human influence has warmed the atmosphere, ocean and land." | 100% | >99% | 194 (Paris parties) | A Major Cathedral Unison Peak (A3, C♯4, E4, A4, C♯5, E5, A5, E6) | 721 / 90 countries | 82,523 | ~8,000+ | 206,478 |
Citation Data Sources: Citation figures are compiled directly from the reference lists printed at the end of each IPCC report chapter, backed by IPCC Secretariat Press Kits & Factsheets ("IPCC in Numbers") and audited by Carbon Brief's Project Cosmos Database (which indexed 107,000+ unique scientific studies across IPCC history from FAR 1990 to AR6 2023).
2. Working Group Breakdown for Major Assessment Cycles
Each major IPCC Assessment Cycle is split into three thematic Working Groups (WGs) and a Synthesis Report (SYR). These numbers offer a secondary, highly granular dataset for mapping layers of polyphony and review intensity.
📖 Detailed Chapter Structure & Metrics (AR6 flagship example)
Detailed breakdown of individual report chapters showing chapter titles, coordinating lead authors (CLAs), lead authors (LAs), review editors (REs), contributing authors (CAs), and literature citations across Working Groups:
| WG / Report | Chapter Number & Title | Core Authors (CLAs / LAs) | Review Editors | Contrib Authors | Citations |
|---|---|---|---|---|---|
| AR6 WGI (Physical Basis) | Ch 1: Framing, Context, Methods | 16 Authors (2 CLAs, 14 LAs) | 3 REs | 42 CAs | ~850 |
| Ch 2: Changing State of Climate System | 19 Authors (2 CLAs, 17 LAs) | 3 REs | 58 CAs | ~1,420 | |
| Ch 3: Human Influence on Climate System | 17 Authors (2 CLAs, 15 LAs) | 3 REs | 45 CAs | ~1,150 | |
| Ch 4: Future Global Climate Projections | 20 Authors (2 CLAs, 18 LAs) | 3 REs | 51 CAs | ~1,280 | |
| Ch 5: Carbon & Biogeochemical Cycles | 21 Authors (3 CLAs, 18 LAs) | 3 REs | 64 CAs | ~1,650 | |
| Ch 6: Short-Lived Climate Forcers | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 38 CAs | ~920 | |
| Ch 7: Energy Budget & Sensitivity | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 49 CAs | ~1,380 | |
| Ch 8: Water Cycle Changes | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 44 CAs | ~1,100 | |
| Ch 9: Ocean, Cryosphere & Sea Level | 21 Authors (3 CLAs, 18 LAs) | 3 REs | 62 CAs | ~1,550 | |
| Ch 10: Linking Global to Regional | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 40 CAs | ~950 | |
| Ch 11: Weather & Climate Extremes | 22 Authors (3 CLAs, 19 LAs) | 3 REs | 67 CAs | ~1,720 | |
| Ch 12: Regional Impact & Risk | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 45 CAs | ~1,130 | |
| WGI Total (13 Chs + Atlas) | 234 Authors (31 CLAs, 167 LAs) | 36 REs | 615 CAs | 13,500 (14,000+) | |
| AR6 WGII (Impacts & Adapt.) | Ch 1: Point of Departure & Key Concepts | 14 Authors (2 CLAs, 12 LAs) | 2 REs | 35 CAs | ~1,200 |
| Ch 2: Terrestrial & Freshwater Ecosystems | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 55 CAs | ~2,800 | |
| Ch 3: Ocean & Coastal Ecosystems | 19 Authors (3 CLAs, 16 LAs) | 3 REs | 58 CAs | ~2,650 | |
| Ch 4: Water Systems & Resources | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 48 CAs | ~2,100 | |
| Ch 5: Food, Fibre & Ecosystem Products | 20 Authors (3 CLAs, 17 LAs) | 3 REs | 52 CAs | ~2,450 | |
| Ch 6: Cities, Settlements & Infrastructure | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 50 CAs | ~2,300 | |
| Ch 7: Health, Wellbeing & Communities | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 42 CAs | ~1,950 | |
| Ch 8: Poverty, Livelihoods & Sustainable Dev | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 38 CAs | ~1,750 | |
| Ch 9: Regional Assessment: Africa | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 45 CAs | ~1,850 | |
| Ch 10: Regional Assessment: Asia | 18 Authors (2 CLAs, 16 LAs) | 2 REs | 46 CAs | ~1,900 | |
| Ch 11: Regional Assessment: Australasia | 14 Authors (2 CLAs, 12 LAs) | 2 REs | 36 CAs | ~1,400 | |
| Ch 12: Regional: Central & South America | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 40 CAs | ~1,650 | |
| Ch 13: Regional Assessment: Europe | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 38 CAs | ~1,600 | |
| Ch 14: Regional Assessment: North America | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 40 CAs | ~1,700 | |
| Ch 15: Regional Assessment: Small Islands | 14 Authors (2 CLAs, 12 LAs) | 2 REs | 35 CAs | ~1,350 | |
| Ch 16: Key Risks Across Sectors & Regions | 18 Authors (3 CLAs, 15 LAs) | 3 REs | 50 CAs | ~2,250 | |
| Ch 17: Decision-Making Options for Risk | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 44 CAs | ~1,900 | |
| Ch 18: Climate Resilient Pathways | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 40 CAs | ~1,700 | |
| WGII Total (18 Chs + 7 Papers) | 270 Authors (47 CLAs, 184 LAs) | 39 REs | 675+ CAs | >34,000 | |
| AR6 WGIII (Mitigation) | Ch 1: Introduction & Framing | 14 Authors (2 CLAs, 12 LAs) | 2 REs | 28 CAs | ~950 |
| Ch 2: Emissions Trends and Drivers | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 32 CAs | ~1,150 | |
| Ch 3: Long-Term Mitigation Pathways | 20 Authors (3 CLAs, 17 LAs) | 3 REs | 45 CAs | ~1,650 | |
| Ch 4: Near to Mid-Term Pathways | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 35 CAs | ~1,250 | |
| Ch 5: Demand, Services & Social Aspects | 18 Authors (2 CLAs, 16 LAs) | 3 REs | 40 CAs | ~1,400 | |
| Ch 6: Energy Systems | 21 Authors (3 CLAs, 18 LAs) | 3 REs | 48 CAs | ~1,850 | |
| Ch 7: Agriculture, Forestry & Land Use | 19 Authors (3 CLAs, 16 LAs) | 3 REs | 42 CAs | ~1,550 | |
| Ch 8: Urban Systems & Settlements | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 30 CAs | ~1,100 | |
| Ch 9: Buildings | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 28 CAs | ~980 | |
| Ch 10: Transport | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 32 CAs | ~1,120 | |
| Ch 11: Industry | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 34 CAs | ~1,200 | |
| Ch 12: Cross-Sectoral Perspectives | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 26 CAs | ~920 | |
| Ch 13: National & Sub-National Policies | 18 Authors (2 CLAs, 16 LAs) | 2 REs | 36 CAs | ~1,350 | |
| Ch 14: International Cooperation | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 28 CAs | ~960 | |
| Ch 15: Investment and Finance | 17 Authors (2 CLAs, 15 LAs) | 2 REs | 35 CAs | ~1,280 | |
| Ch 16: Innovation & Technology Transfer | 16 Authors (2 CLAs, 14 LAs) | 2 REs | 30 CAs | ~1,050 | |
| Ch 17: Accelerating Sustainable Transition | 15 Authors (2 CLAs, 13 LAs) | 2 REs | 25 CAs | ~900 | |
| WGIII Total (17 Chapters) | 278 Authors (36 CLAs, 163 LAs) | 38 REs | 354 CAs | >18,000 | |
| AR5 Cycle (2013) | 60 Chapters across WGI (14), WGII (30), WGIII (16) + SYR (4) | 827 Core Authors | 167 REs | 1,200+ CAs | ~31,000 |
| AR4 Cycle (2007) | 44 Chapters across WGI (11), WGII (20), WGIII (13) + SYR (6) | ~450 Core Authors | 93 REs | 800+ CAs | ~30,000 |
| TAR Cycle (2001) | 43 Chapters across WGI (14), WGII (19), WGIII (10) + SYR (9) | 467 Core Authors | 61 REs | 800+ CAs | ~15,000 |
| SAR Cycle (1995) | 40 Chapters across WGI (11), WGII (18), WGIII (11) | ~476 Core Authors | 44 REs | ~748 CAs | ~10,000 |
| FAR Cycle (1990) | 23 Chapters across WGI (11), WGII (7), WGIII (5) | 97 Core Authors | 15 REs | N/A | 2,315 |
3. Seventh Assessment Cycle (AR7) & Special Reports Timeline (2023–2030)
In July 2023, the IPCC elected its Seventh Assessment Bureau, chaired by Prof. Jim Skea (UK). In January 2024 (IPCC-60, Istanbul), the Panel formally agreed on the work program for the AR7 cycle, scheduled to run through 2030 to inform the UNFCCC's 2nd Global Stocktake under the Paris Agreement.
AR7 Bureau Election
Election of the new IPCC Bureau led by Chair Prof. Jim Skea, establishing leadership across WGI, WGII, WGIII, and TFI.
🏙️ Special Report on Climate Change & Cities
The sole dedicated Special Report approved for AR7. Focuses on urban vulnerability, heat island mitigation, infrastructure resilience, and city-scale decarbonization.
🌫️ Short-Lived Climate Forcers (SLCFs)
Updated national inventory guidelines for estimating emissions of short-lived greenhouse gases (methane, tropospheric ozone, black carbon, hydrofluorocarbons).
🌲 Carbon Dioxide Removal (CDR) & CCUS
Standardized carbon accounting methodology for bioenergy with CCS (BECCS), direct air capture (DACCS), afforestation, and ocean-based CDR technologies.
🌍 AR7 Working Group Reports (WGI, WGII, WGIII)
• WGI (Physical Basis, late 2027/2028): Updated CMIP7 climate projections, climate sensitivity, and carbon budgets.
• WGII (Impacts & Adaptation, 2028): Regional adaptation limits, loss and damage frameworks.
• WGIII (Mitigation, 2028): Net-zero transformation pathways and global sectoral emissions cuts.
🎯 AR7 Synthesis Report (SYR)
Final integrated synthesis report linking WGI, WGII, WGIII, and Special Reports to provide the official scientific input for the UNFCCC 2nd Global Stocktake.
4. Sonification Mapping Schema
To represent the journey from scepticism/uncertainty to consensus, we map the scientific variables to specific musical properties:
Certainty Metric
→Harmonic Consonance / Dissonance
FAR (1990 - ~30% certainty) starts with highly dissonant, tense intervals (Tritones, Minor Seconds). As certainty grows, the friction softens into minor keys (SAR - ~50%), then to bright major thirds and fifths (TAR/AR4), and resolves to pure, perfect unisons, octaves, and fifths (AR6 - 100% Unequivocal).
Participating Authors / Countries
→Polyphony & Register
Early reports are sparse duets. Over time, more voices and instruments enter, expanding the arrangement. Register maps to WGs: WGI forms a low grounded drone/synth bass, WGII is middle-register woodwinds/strings, and WGIII is high-register bright arpeggiators.
Consensus Literature %
→Rhythmic Density / Arpeggiation
Low consensus (1990 - ~50%) plays slow, isolated, drifting pulses. As literature consensus converges towards 99%+, these accelerate into a cascading, shimmering flow of rapid, cohesive arpeggios.
Global Treaty Ratifications
→Spatial Stereo Width & Reverb
With 0 ratifications, the audio is dry, centered, and claustrophobic. As global treaties are signed and ratified (climbing to 194 countries), the panner spreads the voices wide across the stereo field, and the feedback delay reverb expands the room decay to feel global and all-encompassing.
Review Comments Count
→Granular Background Clicks
Addressing the massive volume of peer reviews translates to a percussive click generator. Early reports have almost silence; later cycles (AR5, AR6) create a dense, rustling rain of wood click transients representing the scientific validation of every report statement.
5. Primary References & Data Sources
All metrics, attribution statements, page counts, author figures, and citation totals are compiled from official IPCC publications, UNFCCC treaty databases, and peer-reviewed literature audits:
📚 IPCC Assessment Reports (1990–2023)
- FAR (1990): IPCC First Assessment Report. Cambridge University Press. ipcc.ch/report/1990
- SAR (1995): IPCC Second Assessment Report: Climate Change 1995. Cambridge University Press. ipcc.ch/report/1995
- TAR (2001): IPCC Third Assessment Report: Climate Change 2001. Cambridge University Press. ipcc.ch/report/ar3
- AR4 (2007): IPCC Fourth Assessment Report: Climate Change 2007. Cambridge University Press. ipcc.ch/report/ar4
- AR5 (2013–2014): IPCC Fifth Assessment Report: Climate Change 2013/2014. Cambridge University Press. ipcc.ch/report/ar5
- AR6 (2021–2023): IPCC Sixth Assessment Report: Climate Change 2021–2023. Cambridge University Press. ipcc.ch/report/ar6
🔬 IPCC Special Reports
- SRES (2000): Special Report on Emissions Scenarios. ipcc.ch/sres
- SRCCS (2005): Special Report on Carbon Dioxide Capture and Storage. ipcc.ch/srccs
- SRREN (2011): Special Report on Renewable Energy Sources. ipcc.ch/srren
- SREX (2012): Special Report on Managing the Risks of Extreme Events. ipcc.ch/srex
- SR15 (2018): Special Report on Global Warming of 1.5°C. ipcc.ch/sr15
- SRCCL (2019): Special Report on Climate Change and Land. ipcc.ch/srccl
- SROCC (2019): Special Report on Ocean and Cryosphere in a Changing Climate. ipcc.ch/srocc
🌐 UN Treaties & Consensus Studies
- UNFCCC (1992): United Nations Framework Convention on Climate Change Treaty Text. unfccc.int
- Kyoto Protocol (1997/2005): Kyoto Protocol Status of Ratification. unfccc.int/kyoto
- Paris Agreement (2015/2016): The Paris Agreement Treaty Depositary. unfccc.int/paris
- Oreskes, N. (2004): The Scientific Consensus on Climate Change. Science, 306(5702), 1686. doi:10.1126/science.1103618
- Cook, J., et al. (2013): Quantifying the consensus on anthropogenic global warming in the scientific literature. Environ. Res. Lett. 8 024024. doi:10.1088/1748-9326
📊 Citation Databases & IPCC Metadata
- Carbon Brief (2023): Project Cosmos: Mapping the universe of climate change literature in IPCC reports. Carbon Brief Bibliometric Audit (107,000+ references indexed). carbonbrief.org
- IPCC Secretariat (Geneva): IPCC in Numbers Factsheets & Press Kits (AR4, AR5, AR6). Intergovernmental Panel on Climate Change Media Services. ipcc.ch/news
- Stanhill, G. (2001): The growth of climate change literature: a bibliometric study. Climatic Change, 51(3), 255-275.