View source for Intergovernmental Panel on Climate Change

{{Short description|Scientific intergovernmental body}}
{{redirect|IPCC}}
{{pp-move}}
{{Use dmy dates|date=May 2022}}
{{Infobox organization
| name                = Intergovernmental Panel on Climate Change
| image               = Intergovernmental Panel on Climate Change Logo.svg
| type                = Panel
| abbreviation        = IPCC
| leader_title        = Chair
| leader_name         = [[Jim Skea]]
| leader_title2       = Vice-Chair
| leader_name2        = [[Diana Ürge-Vorsatz]], [[Ramón Pichs Madruga]], [[Ladislaus Chang'a]]
| formation           = {{start date and age|1988|df=yes}}
| headquarters        = [[Geneva]], Switzerland
| website             = {{official URL}}
| parent_organization = [[World Meteorological Organization]]<br />[[United Nations Environment Program]]
}}
{{IPCC}}
The '''Intergovernmental Panel on Climate Change''' ('''IPCC''') is an [[intergovernmental body]] of the [[United Nations]]. Its job is to "provide governments at all levels with scientific information that they can use to develop [[climate policies]]".<ref>{{cite web |title=About the IPCC |url=https://www.ipcc.ch/about/ |access-date=22 February 2019 |publisher=Intergovernmental Panel on Climate Change}}</ref> The [[World Meteorological Organization]] (WMO) and the [[United Nations Environment Programme]] (UNEP) set up the IPCC in 1988. The [[United Nations General Assembly|United Nations]] endorsed the creation of the IPCC later that year.<ref name="UNGA resolution endorsing IPCC">{{cite web |title=UN General Assembly Resolution 43/53 "Protection of global climate for present and future generations of mankind" |url=https://documents-dds-ny.un.org/doc/RESOLUTION/GEN/NR0/530/32/IMG/NR053032.pdf?OpenElement |website=UN General Assembly Resolutions 43rd Session 1988-1989 |publisher=United Nations |access-date=2 April 2022 |archive-date=8 December 2022 |archive-url=https://web.archive.org/web/20221208083351/https://documents-dds-ny.un.org/doc/RESOLUTION/GEN/NR0/530/32/IMG/NR053032.pdf?OpenElement }}</ref> It has a secretariat in [[Geneva]], Switzerland, hosted by the WMO. It has 195 [[Member states of the United Nations|member states]] who govern the IPCC.<ref>{{cite web |title=Annex C to Appendix C to the Principles Governing IPCC Work |url=https://www.ipcc.ch/documentation/procedures/ |website=IPCC Procedures |publisher=IPCC}}</ref> The member states elect a bureau of scientists to serve through an assessment cycle. A cycle is usually six to seven years. The bureau selects experts in their fields to prepare IPCC reports.<ref name="Structure" /> There is a formal nomination process by governments and observer organizations to find these experts. The IPCC has three working groups and a task force, which carry out its scientific work.<ref name="Structure" />

The IPCC informs governments about the state of knowledge of climate change. It does this by examining all the relevant scientific literature on the subject. This includes the natural, [[Economic impacts of climate change|economic]] and social impacts and [[Effects of global warming|risks]]. It also covers possible [[Climate change adaptation|response]] [[Climate change mitigation|options]]. The IPCC does not conduct its own original research. It aims to be objective and comprehensive. Thousands of scientists and other experts volunteer to [[Systematic review|review]] the publications.<ref name="Appendix A to the Principles Governing IPCC Work"/> They compile key findings into "Assessment Reports" for policymakers and the general public;<ref name="Structure">{{cite web |title = Structure of the IPCC | url =https://www.ipcc.ch/about/structure/|publisher = Intergovernmental Panel on Climate Change | access-date=22 February 2019}}</ref> Experts have described this work as the biggest [[peer review]] process in the scientific community.<ref name="AFP unrivalled authority 2021">{{cite news |title=IPCC, the world's unrivalled authority on climate science |url=https://www.france24.com/en/live-news/20210809-ipcc-the-world-s-unrivalled-authority-on-climate-science |agency=AFP |date=9 August 2021}}</ref>

Leading climate scientists and all member governments endorse the IPCC's findings.<ref>{{cite news | title=Scientists offered cash to dispute climate study | date=2 February 2007 | access-date=24 July 2007 | newspaper=Guardian | first=Ian | last=Sample | url=https://www.theguardian.com/frontpage/story/0,,2004399,00.html | quote=[[Lord Rees of Ludlow]], the president of the [[Royal Society]], Britain's most prestigious scientific institute, said: 'The IPCC is the world's leading authority on climate change...' | location=London}}
</ref><ref name="AFP unrivalled authority 2021" /> This underscores that the IPCC is a well-respected authority on climate change. Governments, civil society organizations, and the media regularly quote from the panel's reports. IPCC reports play a key role in the annual climate negotiations held by the [[United Nations Framework Convention on Climate Change]] (UNFCCC).<ref name="UNFCCC intro">{{cite web |title=What is the UNFCCC? |url=https://unfccc.int/process-and-meetings/the-convention/what-is-the-united-nations-framework-convention-on-climate-change |website=UNFCCC }}</ref><ref name="Principles">IPCC. {{cite web |title=Principles Governing IPCC Work |url=https://www.ipcc.ch/documentation/procedures/}}. Approved 1–3 October 1998, last amended 14–18 October 2013.</ref> The IPCC [[Fifth Assessment Report]] was an important influence on the landmark [[Paris Agreement]] in 2015.<ref name="Nature_Schleussner_20160725">{{Cite journal|last1=Schleussner|first1=Carl-Friedrich|last2=Rogelj|author2-link=Joeri Rogelj|first2=Joeri|last3=Schaeffer|first3=Michiel|last4=Lissner|first4=Tabea|last5=Licker|first5=Rachel|last6=Fischer|first6=Erich M.|last7=Knutti|first7=Reto|last8=Levermann|first8=Anders|last9=Frieler|first9=Katja|last10=Hare|first10=William|date=25 July 2016|title=Science and policy characteristics of the Paris Agreement temperature goal|url=http://pure.iiasa.ac.at/id/eprint/13431/1/nclimate3096.pdf|journal=Nature Climate Change|volume=6|issue=9|page=827|bibcode=2016NatCC...6..827S|doi=10.1038/nclimate3096}}</ref> The IPCC shared the [[2007 Nobel Peace Prize]] with [[Al Gore]] for contributions to the understanding of climate change.<ref>{{cite web |title=The Nobel Peace Prize 2007 |url=https://www.nobelprize.org/prizes/peace/2007/summary/ |website=The Nobel Prize |publisher=Nobel Prize Outreach}}</ref>

The seventh assessment cycle of the IPCC began in 2023. In August 2021, the IPCC published its Working Group I contribution to the [[IPCC Sixth Assessment Report|Sixth Assessment Report]] on the physical science basis of climate change.<ref name=":6">IPCC, 2021: ''[https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Climate Change 2021: The Physical Science Basis]. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change''[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, New York, US, In press, doi:10.1017/9781009157896.</ref> ''[[The Guardian]]'' described this report as the "starkest warning yet" of "major inevitable and irreversible climate changes".<ref name="Guardian 9Aug21">{{cite news |last=Harvey |first=Fiona |author-link=Fiona Harvey |date=9 August 2021 |title=Major climate changes inevitable and irreversible – IPCC's starkest warning yet |url=https://www.theguardian.com/science/2021/aug/09/humans-have-caused-unprecedented-and-irreversible-change-to-climate-scientists-warn |work=[[The Guardian]]}}</ref> Many newspapers around the world echoed this theme.<ref name="Guardian 10Aug21">{{cite news|last=Sullivan|first=Helen|date=10 August 2021|title='Code red for humanity': what the papers say about the IPCC report on the climate crisis|work=[[The Guardian]]|url=https://www.theguardian.com/environment/2021/aug/10/code-red-for-humanity-what-the-papers-say-about-the-ipcc-report-on-the-climate-crisis}}</ref> In February 2022, the IPCC released its Working Group II report on impacts and adaptation.<ref>{{Cite web|url=https://www.ipcc.ch/report/ar6/wg2/|title = Climate Change 2022: Impacts, Adaptation, and Vulnerability}}</ref> It published Working Group III's "mitigation of climate change" contribution to the Sixth Assessment in April 2022.<ref>{{Cite web|url=http://www.ipcc.ch/report/ar6/wg3/resources/press/press-release |title= Mitigation of climate change }}</ref> The Sixth Assessment Report concluded with a Synthesis Report in March 2023.

During the period of the Sixth Assessment Report, the IPCC released three special reports. The first and most influential was the [[Special Report on Global Warming of 1.5 °C|Special Report on Global Warming of 1.5°C]] in 2018. In 2019 the [[Special Report on Climate Change and Land]], and the [[Special Report on the Ocean and Cryosphere in a Changing Climate]] came out. The IPCC also updated its methodologies in 2019. So the sixth assessment cycle was the most ambitious in the IPCC's history.<ref>{{cite web |title=Decisions adopted by the 43rd Session of the Panel |url=https://www.ipcc.ch/site/assets/uploads/2018/05/p43_decisions.pdf |page= 11 decision 6}}</ref>

{{TOC level|3}}

== Origins ==
The predecessor of the IPCC was the [[Advisory Group on Greenhouse Gases]] (AGGG).<ref>{{cite journal |last1=Potter |first1=Thomas D. |title=Advisory Group on Greenhouse Gases Established Jointly by WMO, UNEP, and ICSU |journal=Environmental Conservation |date=Winter 1986 |volume=13 |issue=4 |page=365 |doi=10.1017/S0376892900035505 |s2cid=84551617 |doi-access=free |bibcode=1986EnvCo..13..365P }}</ref> Three organizations set up the AGGG in 1986. These were the [[International Council for Science|International Council of Scientific Unions]], the [[United Nations Environment Programme]] (UNEP), and the [[World Meteorological Organization]] (WMO). The AGGG reviewed scientific research on greenhouse gases. It also studied increases in greenhouse gases. [[Climate Science|Climate science]] was becoming more complicated and covering more disciplines. This small group of scientists lacked the resources to cover climate science.

The [[United States Environmental Protection Agency]] sought an international convention to restrict [[greenhouse gas emissions]]. The [[Presidency of Ronald Reagan|Reagan Administration]] worried that independent scientists would have too much influence. The WMO and UNEP therefore created the IPCC as an intergovernmental body in 1988. Scientists take part in the IPCC as both experts and government representatives. The IPCC produces reports backed by all leading relevant scientists. Member governments must also endorse the reports by consensus agreement. So the IPCC is both a scientific body and an organization of governments.<ref>{{Cite book |last=Weart |first=Spencer R. |title=[[The Discovery of Global Warming]] |date=2008 |isbn=978-0-674-41755-7 |edition=Revised and expanded |location=Cambridge, Mass. |chapter=Democracy and Policy Advice (1980s) |oclc=872115457 |archive-url=https://web.archive.org/web/20131109135754/http://www.aip.org/history/climate/internat.htm#S9 |archive-date=9 November 2013 |chapter-url=http://www.aip.org/history/climate/internat.htm#S9}}</ref><ref>{{Cite web|url=https://www.ipcc.ch/site/assets/uploads/2021/07/AR6_FS_What_is_IPCC.pdf|title=IPCC Factsheet: What is the IPCC?}}</ref> Its job is to tell governments what scientists know about climate change. It also examines the [[Effects of climate change|impacts of climate change]] and options for dealing with it. The IPCC does this by assessing peer-reviewed scientific literature.<ref>{{Cite journal |last1=Hulme |first1=Mike |last2=Mahony |first2=Martin |date=October 2010 |title=Climate change: What do we know about the IPCC? |url=http://journals.sagepub.com/doi/10.1177/0309133310373719 |journal=Progress in Physical Geography: Earth and Environment |language=en |volume=34 |issue=5 |pages=705–718 |doi=10.1177/0309133310373719 |bibcode=2010PrPG...34..705H |s2cid=130711399 |issn=0309-1333|url-access=subscription }}</ref>

The [[United Nations]] endorsed the creation of the IPCC in 1988. The [[General Assembly resolution]] noted that human activity could change the climate. This could lead to severe economic and social consequences. It said increasing concentrations of greenhouse gases could [[Instrumental temperature record|warm the planet]]. This would cause the [[Sea level rise|sea level to rise]]. The effects on humanity would be disastrous if timely steps were not taken.<ref name="UNGA resolution endorsing IPCC" />

== Organization ==
[[File:IPCC adoption of the Summary for Policymakers of the Special Report on Global Warming of 1.5°C.jpg|upright=1.2|thumb|Adoption of the Summary for Policymakers of the IPCC [[Special Report on Global Warming of 1.5 °C|Special Report on Global Warming of 1.5°C]] in 2018]]

=== Way of working ===
The IPCC does not conduct original research.<ref>{{Cite web |title=What is the IPCC? |url=https://eciu.net/analysis/briefings/climate-science-the-basics/what-is-the-ipcc |access-date=2022-11-08 |website=Energy & Climate Intelligence Unit |date=18 October 2021 |language=en}}</ref> It produces comprehensive assessments on the state of knowledge of climate change. It prepares reports on special topics relevant to climate change. It also produces methodologies. These methodologies help countries estimate their greenhouse gas emissions and removals through sinks. Its assessments build on previous reports and scientific publications. Throughout six assessments the reports reflect the growing evidence for a changing climate. And they show how this is due to human activity.

=== Rules and governing principles ===
The IPCC has adopted its rules of procedure in the "Principles Governing IPCC Work". These state that the IPCC will assess:<ref name="Principles"/>
* the risk of [[Global warming|climate change]] caused by human activities,
* its [[Effects of global warming|potential impacts]], and
* possible [[Climate change mitigation|options for prevention]].
Under IPCC rules its assessments are comprehensive, objective, open, and transparent. They cover all the information relevant to the scientific understanding of climate change. This draws on scientific, technical, and socioeconomic information. IPCC reports must be neutral regarding policy recommendations. However, they may address the objective factors relevant to enacting policies.<ref name="Principles"/>

=== Structure ===
The IPCC has the following structure:
* IPCC Panel: Meets in [[plenary session]] about twice a year. It may meet more often for the approval of reports.<ref name="Structure" /> It controls the IPCC's structure, procedures, work programme, and budget. It accepts and approves IPCC reports. The Panel is the IPCC corporate entity.<ref name="Structure"/>
* Chair: Elected by the Panel. Chairs the Bureau and other bodies. Represents the organization.
* Bureau: Elected by the Panel. It currently has 34 members from different geographic regions. Besides the Chair and three IPCC Vice-Chairs, they provide the leadership for the IPCC's three Working Groups and Task Force.<ref name="IPCC Bureau">{{Cite web|url=https://www.ipcc.ch/bureau/|title=Bureau Portal — IPCC|access-date=9 August 2019}}</ref> It provides guidance to the Panel on the scientific and technical aspects of its work.<ref>{{cite web |title=The IPCC Bureau |url=https://www.ipcc.ch/bureau/ |website=The IPCC Bureau (see Terms of Reference) |publisher=IPCC}}</ref>
* Working Groups: Each has two Co-Chairs, one from a developed and one from a developing country. A technical support unit supports each Working Group. Working Group sessions approve the Summary for Policymakers of assessment and special reports. Each Working Group has a Bureau. This consists of its Co-Chairs and Vice-Chairs, who are also members of the IPCC Bureau.
** Working Group I: Assesses scientific aspects of the climate system and climate change. Co-Chairs: Robert Vautard (France) and Xiaoye Zhang (China)<ref name=":9">{{Cite web |title=IPCC wraps up elections in Nairobi — IPCC |url=https://www.ipcc.ch/2023/07/28/ipcc-wraps-up-elections-in-nairobi/ |access-date=2023-07-29}}</ref>
** Working Group II: Assesses the impacts of climate change on human and natural systems. Assesses adaptation options. Co-Chairs: Bart van den Hurk (Netherlands) and Winston Chow (Singapore)<ref name=":9" />
** Working Group III: Assesses how to stop climate change by limiting greenhouse gas emissions. (Known as "mitigation".) Co-Chairs: [[Katherine Calvin]] (United States) and Joy Jacqueline Pereira (Malaysia)<ref name=":9" />
* Task Force on National Greenhouse Gas Inventories.<ref name=":5">{{cite web |title=Task Force on National Greenhouse Gas Inventories |url=https://www.ipcc.ch/working-group/tfi/ |access-date=25 February 2019}}</ref> Develops methodologies for estimating greenhouse gas emissions. Co-Chairs: Takeshi Enoki (Japan) and Mazhar Hayat (Pakistan)<ref name=":9" />
** Task Force Bureau: Consists of two Co-Chairs, who are also members of the IPCC Bureau, and 12 members.
* Executive Committee: Consists of the Chair, IPCC Vice-Chairs and the Co-Chairs of the Working Groups and Task Force. It addresses urgent issues that arise between sessions of the Panel.<ref>{{cite web |title=Structure of the IPCC - The Executive Committee |url=https://www.ipcc.ch/about/structure/ |website=Structure of the IPCC |ref=(see Terms of Reference of the Executive Committee)}}</ref>
* Secretariat: Administers activities, supports the Chair and Bureau, point of contact for governments. Supported by UNEP and the WMO.<ref>{{Cite web|url=https://www.ipcc.ch/site/assets/uploads/2018/09/IAC_Secretariat_TSU.pdf|title=Terms of Reference of the IPCC Secretariat}}</ref>

==== Chair ====
The chair of the IPCC is British energy scientist [[James Skea|Jim Skea]], who is hosted by the [[International Institute for Environment and Development]]. Skea has served since 28 July 2023 with the election of the new IPCC Bureau.<ref>{{Cite web |title=IPCC elects Jim Skea as the new Chair — IPCC |url=https://www.ipcc.ch/2023/07/26/jim-skea-new-ipcc-chair/ |access-date=2023-07-29}}</ref><ref name=":9" /> His predecessor was Korean economist [[Hoesung Lee]], elected in 2015. The previous chairs were [[Rajendra K. Pachauri]], elected in 2002, [[Robert Watson (scientist)|Robert Watson]], elected in 1997, and [[Bert Bolin]], elected in 1988.<ref>{{Cite web|url=https://www.ipcc.ch/site/assets/uploads/2019/03/16th-anniversary-brochure.pdf|title=16 Years of Scientific Assessment in Support of the Climate Convention}}</ref>

==== Panel ====
The Panel consists of representatives appointed by governments. They take part in plenary sessions of the IPCC and its Working Groups. Non-governmental and intergovernmental organizations may attend as observers.<ref>{{cite web |title=Structure of the IPCC - Observer Organizations |url=https://www.ipcc.ch/about/structure/ |website=IPCC }}</ref> Meetings of IPCC bodies are by invitation only.<ref name="Principles" /> About 500 people from 130 countries attended the 48th Session of the Panel in Incheon, Republic of Korea. This took place in October 2018. They included 290 government officials and 60 representatives of observer organizations. The opening ceremonies of sessions of the Panel and of Lead Author Meetings are open to media. Otherwise, IPCC meetings are closed.

=== Funding ===
The IPCC receives funding through a dedicated [[Trust law|trust fund]]. UNEP and the WMO established the fund in 1989. The trust fund receives annual financial contributions from member governments. The WMO, UNEP, and other organizations also contribute. Payments are voluntary and there is no set amount required. The WMO covers the operating costs of the secretariat. It also sets the IPCC's financial regulations and rules.<ref>{{cite web |title=IPCC Procedures - Appendix B to the Principles Governing IPCC Work: Financial Procedures for the Intergovernmental Panel on Climate Change |url=https://www.ipcc.ch/documentation/procedures/ |website=IPCC Procedures |publisher=IPCC}}</ref> The Panel sets the annual budget.

In 2021, the IPCC's annual budget amounts to approximately six million euros, financed by the 195 UN Member states, who contribute "independently and voluntarily".<ref name=":8">{{Cite web |last=Beaujon |first=Agathe |date=2021-08-09 |title=Changement climatique: Le Giec quésaco? |url=https://www.challenges.fr/green-economie/changement-climatique-5-chiffres-pour-comprendre-comment-fonctionne-le-giec_776157 |access-date=2023-07-02 |website=Challenges |language=fr}}</ref><ref>{{Cite web |title=Comprendre le GIEC |url=https://www.ecologie.gouv.fr/comprendre-giec |access-date=2023-07-02 |website=Ministères Écologie Énergie Territoires |language=fr}}</ref> In 2021, the countries giving the most money include the United States, Japan, France, Germany and Norway.<ref name=":8" /> Other countries, often developing ones, give an "in-kind contribution, by hosting IPCC meetings".<ref name=":8" /> In 2022, this budget was a little less than eight million euros.<ref name=":8" />

=== List of all reports ===
{| class="wikitable sortable"
!Year
!Name of report
!Type of report
|-
|2023
|AR6 Synthesis Report: ''Climate Change 2023'' (March 2023)
|Synthesis Report
|-
|2021 and 2022
|[[IPCC Sixth Assessment Report|Sixth Assessment Report]] (AR6): ''Climate Change 2021: The Physical Science Basis'' (Working Group I, August 2021), ''Climate Change 2022: Impacts, Adaptation and Vulnerability'' (Working Group II, February 2022), ''Mitigation of Climate Change'' (Working Group III, April 2022)
|Assessment Report (Working Group contributions)
|-
|2019
|[[Special Report on the Ocean and Cryosphere in a Changing Climate]]
|Special Report
|-
|2019
|[[Special Report on Climate Change and Land]]
|Special Report
|-
|2019
|2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories<ref>IPCC 2019, 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Calvo Buendia, E., Tanabe, K., Kranjc, A., Baasansuren, J., Fukuda, M., Ngarize, S., Osako, A., Pyrozhenko, Y., Shermanau, P. and Federici, S. (eds). Published: IPCC, Switzerland.</ref>
|Methodology Report
|-
|2018
|[[Special Report on Global Warming of 1.5 °C|Special Report on Global Warming of 1.5&nbsp;°C]] (SR15)
|Special Report
|-
|2014
|AR5 Synthesis Report: ''Climate Change 2014''<ref>IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.</ref>
|Synthesis Report
|-
|2013 and 2014
|[[Fifth Assessment Report]] (AR5) ''Climate Change 2013: The Physical Science Basis'' (Working Group I, September 2013), ''Climate Change 2014: Impacts, Adaptation and Vulnerability'' (Working Group II, March 2014), ''Climate Change 2014: Mitigation of Climate Change'' (Working Group III, April 2014)
|Assessment (Working Group contributions)
|-
|2013
|2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands<ref>IPCC 2014, 2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands, Hiraishi, T., Krug, T., Tanabe, K., Srivastava, N., Baasansuren, J., Fukuda, M. and Troxler, T.G. (eds). Published: IPCC, Switzerland.</ref>
|Methodology Report
|-
|2013
|2013 Revised Supplementary Methods and Good Practice Guidance Arising from the Kyoto Protocol<ref>IPCC 2014, 2013 Revised Supplementary Methods and Good Practice Guidance Arising from the Kyoto Protocol, Hiraishi, T., Krug, T., Tanabe, K., Srivastava, N., Baasansuren, J., Fukuda, M. and Troxler, T.G. (eds) Published: IPCC, Switzerland.</ref>
|Methodology Report
|-
|2011
|Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation<ref>IPCC, 2012: [https://www.ipcc.ch/report/managing-the-risks-of-extreme-events-and-disasters-to-advance-climate-change-adaptation/ Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change] [Field, C.B., V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.-K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, UK, and New York, New York, US, 582 pp.</ref>
|Special Report
|-
|2011
|Renewable Energy Sources and Climate Change Mitigation<ref>IPCC, 2011 – Ottmar Edenhofer, Ramón Pichs-Madruga, Youba Sokona, Kristin Seyboth, Patrick Matschoss, Susanne Kadner, Timm Zwickel, Patrick Eickemeier, Gerrit Hansen, Steffen Schloemer, Christoph von Stechow (Eds.)

Cambridge University Press, Cambridge, United Kingdom and New York, New York, US, 1075 pp.</ref>
|Special Report
|-
|2007
|AR4 Synthesis Report: ''Climate Change 2007''
|Synthesis Report
|-
|2007
|[[IPCC Fourth Assessment Report|Fourth Assessment Report]] (AR4) ''Climate Change 2007: The Physical Science Basis'' (Working Group I, February 2007), ''Climate Change 2007: Impacts, Adaptation, and Vulnerability'' (Working Group II, April 2007), ''Climate Change 2007: Mitigation of Climate Change'' (Working Group III, May 2007)
|Assessment Report (Working Group contributions)
|-
|2006
|2006 IPCC Guidelines for National Greenhouse Gas Inventories
|Methodology Report
|-
|2005
|Safeguarding the Ozone Layer and the Global Climate System
|Special Report
|-
|2005
|Carbon Dioxide Capture and Storage<ref name=":02">IPCC, 2005: [https://www.ipcc.ch/report/carbon-dioxide-capture-and-storage/ IPCC Special Report on Carbon Dioxide Capture and Storage]. Prepared by Working Group III of the Intergovernmental Panel on Climate Change [Metz, B., O. Davidson, H. C. de Coninck, M. Loos, and L. A. Meyer (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, New York, US, 442 pp.</ref>
|Special Report
|-
|2003
|Good Practice Guidance for Land Use, Land-Use Change and Forestry
|Methodology Report
|-
|2003
|Definitions and Methodological Options to Inventory Emissions from Direct Human-induced Degradation of Forests and Devegatation of Other Vegetation Types
|Methodology Report
|-
|2001
|TAR Synthesis Report: ''Climate Change 2001''
|Synthesis Report
|-
|2001
|[[Third Assessment Report]] (TAR) ''Climate Change 2001: The Scientific Basis'' (Working Group I), ''Climate Change 2001: Impacts, Adaptation, and Vulnerability'' (Working Group II), ''Climate Change 2001: Mitigation'' (Working Group III)
|Assessment Report (Working Group contributions)
|-
|2000
|Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories
|Methodology Report
|-
|2000
|Methodological and Technological Issues in Technology Transfer
|Special Report
|-
|2000
|Land Use, Land-Use Change, and Forestry
|Special Report
|-
|2000
|[[Special Report on Emissions Scenarios]]
|Special Report
|-
|1999
|Aviation and the Global Atmosphere
|Special Report
|-
|1997
|The Regional Impacts of Climate Change: An Assessment of Vulnerability
|Special Report
|-
|1996
|Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories
|Methodology Report
|-
|1996
|SAR Synthesis Report: ''Climate Change 1995''
|Synthesis Report
|-
|1995
|[[IPCC Second Assessment Report|Second Assessment Report]] (SAR) ''Climate Change 1995: The Science of Climate Change'' (Working Group I), ''Climate Change 1995: Impacts, Adaptations and Mitigation of Climate Change: Scientific-Technical Analyses'' (Working Group II), ''Climate Change 1995: Economic and Social Dimensions of Climate Change'' (Working Group III)
|Assessment Report (Working Group contributions)
|-
|1994
|IPCC Guidelines for National Greenhouse Gas Inventories
|Methodology Report
|-
|1994
|Climate Change 1994: Radiative Forcing of Climate Change and An Evaluation of the IPCC IS92 Emission Scenarios
|Special Report
|-
|1994
|IPCC Technical Guidelines for Assessing Climate Change Impacts and Adaptations
|Special Report
|-
|1992
|FAR ''Climate Change: The IPCC 1990 and 1992 Assessments'' (June 1992) (includes an Overview of the whole report)
|Assessment Report (Working Group contributions)/Synthesis Report
|-
|1992
|FAR ''Climate Change 1992: The Supplementary Report to the IPCC Scientific Assessment'' (Working Group I, February 2022), ''Climate Change 1992: The Supplementary Report to the IPCC Impacts Assessment'' (Working Group II, February 2022)
|Assessment Report (Working Group contributions)
|-
|1990
|[[IPCC First Assessment Report|First Assessment Report]] (FAR) ''Climate Change: The IPCC Scientific Assessment'' (Working Group I), ''Climate Change: The IPCC Impacts Assessment'' (Working Group II), ''Climate Change: The IPCC Response Strategies'' (Working Group III)
|Assessment Report (Working Group contributions)
|}

=== Activities other than report preparation ===
The IPCC bases its work on the decisions of the WMO and UNEP, which established the IPCC. It also supports the work of the UNFCCC.<ref name="Principles" /> The main work of the IPCC is to prepare assessments and other reports. It also supports other activities such as the Data Distribution Centre.<ref>{{cite web |title=Welcome to the IPCC Data Distribution Centre |url=http://www.ipcc-data.org/ |access-date=25 June 2012 |publisher=Ipcc-data.org |archive-date=19 May 2016 |archive-url=https://web.archive.org/web/20160519152028/http://www.ipcc-data.org/ }}</ref> This helps manage data related to IPCC reports.

The IPCC has a "Gender Policy and Implementation Plan" to pay attention to gender in its work. It aims to carry out its work inclusively and respectfully. The IPCC aims for balance in participation in IPCC work. This should offer all participants equal opportunity.<ref>{{Cite web |title=Gender — IPCC |url=https://www.ipcc.ch/about/gender/ |access-date=2022-10-21}}</ref>

==== Communications and dissemination activities ====
The IPCC enhanced its communications activities for the Fifth Assessment Report. For instance, it made the approved report and press release available to registered media under embargo before the release.<ref>{{cite web |date=21 February 2014 |title=IPCC Media Advisory: IPCC Working Group II and Working Group III Reports, 2014 |url=https://www.ipcc.ch/2014/02/21/ipcc-working-group-ii-and-working-group-iii-reports/ |access-date=24 March 2022}}</ref> And it expanded its outreach activities with an outreach calendar.<ref>{{Cite web|url=https://archive.ipcc.ch/apps/outreach/index.php|title=Outreach - Programme|website=archive.ipcc.ch}}</ref> The IPCC held an Expert Meeting on Communication in February 2016, at the start of the Sixth Assessment Report cycle. Members of the old and new Bureaus worked with communications experts and practitioners at this meeting. This meeting produced a series of recommendations.<ref>{{Cite web|url=https://www.ipcc.ch/event/ipcc-expert-meeting-on-communication/|title=IPCC Expert Meeting on Communication — IPCC}}</ref> The IPCC adopted many of them. One was to bring people with communications expertise into the Working Group Technical Support Units. Another was to consider communication questions early on in the preparation of reports.

Following these steps in communications, the IPCC saw a significant increase in media coverage of its reports. This was particularly the case with the ''[[Special Report on Global Warming of 1.5 °C]]'' in 2018 and ''Climate Change 2021: The Physical Science Basis'', the Working Group I contribution to the [[IPCC Sixth Assessment Report|Sixth Assessment Report]], in 2021. There was also much greater public interest, reflected in the youth and other movements that emerged in 2018.<ref name=":4">{{Cite web|url=https://www.ipcc.ch/site/assets/uploads/2019/01/010520190905-INF.-9Coms.pdf|title=Progress Report on Communication and Outreach Activities to the 49th Session of the IPCC, 2019}}</ref>

IPCC reports are important for [[public awareness of climate change]] and related policymaking. This has led to several academic studies of IPCC communications, for example in 2021.<ref>{{cite web |last=O'Neill |first=Saffron |date=5 October 2021 |title=Launch of the Topical Collection: Climate change communication and the IPCC, 2021 |url=https://saffrononeill.com/research_projects/si_cc_comms_ipcc/ |publisher=}}</ref><ref>{{Cite journal |last1=O'Neill |first1=Saffron |last2=Pidcock |first2=Roz |date=2021 |title=Introducing the Topical Collection: 'Climate change communication and the IPCC' |journal=Climatic Change |language=en |volume=169 |issue=3 |page=19 |bibcode=2021ClCh..169...19O |doi=10.1007/s10584-021-03253-3 |issn=1573-1480 |pmc=8638646 |pmid=34876762}}</ref>

==== Archiving ====
The IPCC archives its reports and electronic files on its website. They include the review comments on drafts of reports. The Environmental Science and Public Policy Archives in the [[Harvard Library]] also archives them.<ref>{{Cite web |date=2010-04-27 |title=Papers of the Intergovernmental Panel on Climate Change - Harvard College Library |url=http://hcl.harvard.edu/collections/ipcc/ |archive-url=https://web.archive.org/web/20100427023820/http://hcl.harvard.edu/collections/ipcc/ |archive-date=2010-04-27 |access-date=2022-10-27}}</ref>

==Assessment reports==

{{Main|IPCC First Assessment Report|IPCC Second Assessment Report|IPCC Third Assessment Report|IPCC Fourth Assessment Report|IPCC Fifth Assessment Report|IPCC Sixth Assessment Report}}
[[File:Ipcc assessments pages.png|thumb|Page counts of the six IPCC Assessment Reports (1990 to 2021)]]
Between 1990 and 2023, the IPCC published six comprehensive assessment reports reviewing the latest climate science. The IPCC has also produced 14 special reports on particular topics.<ref name="UCS IPCC Who are they?">{{cite web |title=The IPCC: Who Are They and Why Do Their Climate Reports Matter? |url=https://www.ucsusa.org/resources/ipcc-who-are-they |website=Union of Concerned Scientists: Reports & Multimedia - Activist Resources: Explainers |publisher=Union of Concerned Scientists |date=11 October 2018}}</ref> Each assessment report has four parts. These are a contribution from each of the three working groups, plus a synthesis report. The synthesis report integrates the working group contributions. It also integrates any special reports produced in that assessment cycle.

=== Review process of scientific literature ===
The IPCC does not carry out research. It does not monitor climate-related data. The reports by IPCC assess scientific papers and independent results from other scientific bodies. The IPCC sets a deadline for publication of scientific papers that a report will cover. That report will not include new information that emerges after this deadline. However, there is a steady evolution of key findings and levels of [[confidence interval|scientific confidence]] from one assessment report to the next.<ref>{{Cite news |date=9 August 2021 |title=Climate change: Five things we have learned from the IPCC report |work=BBC News |url=https://www.bbc.com/news/science-environment-58138714 |access-date=12 August 2021}}</ref> Each IPCC report notes areas where the science has improved since the previous report. It also notes areas that would benefit from further research.

The [[IPCC First Assessment Report|First Assessment Report]] was published in 1990 and received an update in 1992.<ref>{{Cite web |title=Climate Change: The IPCC 1990 and 1992 Assessments — IPCC |url=https://www.ipcc.ch/report/climate-change-the-ipcc-1990-and-1992-assessments/ |url-status=live |archive-url=https://web.archive.org/web/20210904134132/https://www.ipcc.ch/report/climate-change-the-ipcc-1990-and-1992-assessments/ |archive-date=2021-09-04 |access-date=2021-09-04}}</ref> In intervals of about six years, new editions of IPCC Assessment Report followed.

===Selection and role of authors===
The focal points of the Member states — the individual appointed by each state to liaise with the IPCC — and the observer organizations submit to the IPCC Bureau a list of personalities, which they have freely constituted. The Bureau (more precisely, the co-chairs of the relevant working group, with the help of its technical support unit) uses these lists as a basis for appointing authors while retaining the possibility of appointing people who are not on the list, primarily based on scientific excellence and diversity of viewpoints, and to a lesser extent by ensuring geographical diversity, experience within the IPCC and gender. Authors may include, in addition to researchers, personalities from the private sector and experts from NGOs.<ref>{{Cite web |title=Q&A: How IPCC reports get written, why they matter and what role governments play in them |url=https://www.sei.org/featured/faq-ipcc-report/ |access-date=2023-07-02 |website=SEI |language=en-GB}}</ref><ref>{{Cite web |title=IPCC Factsheet: How does the IPCC select its authors? |url=https://www.ipcc.ch/site/assets/uploads/2018/02/FS_select_authors.pdf |website=IPCC}}</ref><ref>{{Cite book |first=Adam |last=Standring|title=A critical assessment of the intergovernmental panel on climate change |chapter=Participant Selection|date=2023 |publisher=Cambridge University Press |isbn=978-1-316-51427-6 |editor-last=De Pryck |editor-first=Kari |location=Cambridge New York, NY Port Melbourne, VIC New Delhi Singapore |pages=63–66 |editor-last2=Hulme |editor-first2=Mike}}</ref><ref>{{Cite book |last=De Pryck |first=Kari |title=GIEC, la voix du climat |date=2022 |publisher=Sciences po, les presses |isbn=978-2-7246-3870-7 |series=Collection académique |location=Paris |pages=43, 66–69}}</ref>

The IPCC Bureau or Working Group Bureau selects the authors of the reports from government nominations. Lead authors of IPCC reports assess the available information about climate change based on published sources.<ref name="Appendix A to the Principles Governing IPCC Work">{{Cite web |title=Procedures |website=IPCC |url=https://www.ipcc.ch/documentation/procedures/ |access-date=2022-10-04}}
</ref><ref>IPCC. [https://www.ipcc.ch/about/ About the IPCC]</ref> According to IPCC guidelines, authors should give priority to [[Peer review|peer-reviewed]] sources.<ref name="Appendix A to the Principles Governing IPCC Work" /> Authors may refer to non-peer-reviewed sources ("grey literature"), if they are of sufficient quality.<ref name="Appendix A to the Principles Governing IPCC Work" /> These could include reports from government agencies and non-governmental organizations. Industry journals and [[Climate model|model results]] are other examples of non-peer-reviewed sources.<ref name="Appendix A to the Principles Governing IPCC Work" />

Authors prepare drafts of a full report divided into chapters. They also prepare a technical summary of the report, and a [[IPCC Summary for Policymakers|summary for policymakers]].<ref name="Appendix A to the Principles Governing IPCC Work" />

Each chapter has many authors to write and edit the material. A typical chapter has two coordinating lead authors, ten to fifteen lead authors, and a larger number of contributing authors. The coordinating lead authors assemble the contributions of the other authors. They ensure that contributions meet stylistic and formatting requirements. They report to the Working Group co-chairs. Lead authors write sections of chapters. They invite contributing authors to prepare text, graphs, or data for inclusion.<ref name=":3">{{cite web
 |url= https://www.ipcc.ch/site/assets/uploads/2018/02/FS_select_authors.pdf
 |title= IPCC Factsheet: How does the IPCC select its authors?
 |date= 30 August 2013
|access-date= 12 October 2018
}}</ref> Review editors must ensure that authors respond to comments received during the two stages of drafts review: the first is only open to external experts and researchers, while the second is also open to government representatives.<ref>{{Cite web |title=Guidance Note of the Role of Review Editors of the Working Group I Sixth Assessment Report (WGI AR6) |url=https://www.ipcc.ch/site/assets/uploads/2017/08/AR6_WGI_Guidance_note_Role_REs.pdf |website=IPCC}}</ref><ref>{{Cite web |title=Registration opens for Expert Review of IPCC Working Group II contribution to IPCC Sixth Assessment Report — IPCC |url=https://www.ipcc.ch/2019/10/11/wg2-ar6-first-order-draft-expert-review/ |access-date=2023-07-01}}</ref>

The Bureau aims for a range of views, expertise, and geographical representation in its choice of authors. This ensures the author team includes experts from both developing and developed countries. The Bureau also seeks a balance between male and female authors. It aims for a balance between those who have worked previously on IPCC reports and those new to the process.<ref name=":3" />

Scientists who work as authors on IPCC reports do not receive any compensation for this work, and all work voluntarily.<ref name=":7">{{Cite book |last=De Pryck |first=Kari |title=GIEC, la voix du climat |date=2022 |publisher=Sciences po, les presses |isbn=978-2-7246-3870-7 |series=Collection académique |location=Paris |pages=65–66}}</ref> They depend on the salaries they receive from their home institutions or other work. The work is labour-intensive with a big time commitment. It can disrupt participating scientists' research. This has led to concern that the IPCC process may discourage qualified scientists from participating.<ref>{{Cite book |author1=Committee on Analysis of Global Change Assessments |url=http://www.nap.edu/catalog/11868.html#toc |title=Analysis of Global Change Assessments: Lessons Learned |author2=Board on Atmospheric Sciences and Climate |author3=Division of Earth and Life Sciences |publisher=[[National Academies Press]] |year=2007 |isbn=978-0-309-10485-2 |access-date=24 July 2007}}</ref><ref>{{Cite book |title=Climate change science: an analysis of some key questions |date=2001 |publisher=National Academy Press |others=National Research Council. Committee on the Science of Climate Change |isbn=0-309-52872-0 |location=Washington, D.C. |oclc=52816599}}</ref> More than 3,000 authors (coordinating lead authors, lead authors, review editors) have participated in the drafting of IPCC reports since its creation.<ref name=":7" />

=== Review process for assessment reports ===
Expert reviewers comment at different stages on the drafts.<ref>{{cite web |last1=IPCC |title=IPCC Factsheet: How does the IPCC review process work? |url=https://www.ipcc.ch/site/assets/uploads/2018/02/FS_review_process.pdf |access-date=18 January 2018 |website=Intergovernmental Panel on Climate Change |publisher=IPCC}}</ref> Reviewers come from member governments and IPCC observers. Also, anyone may become an IPCC reviewer by stating they have the relevant expertise.

There are generally three stages in the review process.<ref name="Appendix A to the Principles Governing IPCC Work" /> First comes an expert review of the first draft of the chapters. The next stage is a review by governments and experts of the revised draft of the chapters and the first draft of the Summary for Policymakers. The third stage is a government review of the revised Summary for Policymakers. Review comments and author responses remain in an open archive for at least five years. Finally, government representatives together with the authors review the Summary for Policymakers. They go through the Summary for Policymakers line by line to ensure it is a good summary of the underlying report. This final review of the Summary of Policymakers takes place at sessions of the responsible working group or of the Panel.

There are several types of endorsement that documents receive:
* Approval - Material has been subject to detailed, line-by-line discussion and agreement. (The relevant Working Groups ''approve'' Working Group Summaries for Policymakers. The Panel ''approves'' the Synthesis Report Summary for Policymakers.)
* Adoption - Endorsed section by section (not line by line). (The Panel ''adopts'' the full IPCC Synthesis Report. It also ''adopts'' Overview Chapters of Methodology Reports.)
* Acceptance - Not been subject to line-by-line discussion and agreement. But it presents a comprehensive, objective, and balanced view of the subject matter. (Working Groups ''accept'' their reports. The Panel ''accepts'' Working Group Summaries for Policymakers after working group approval. The Panel ''accepts'' Methodology Reports.)

=== Key findings and impacts ===
==== Assessment reports one to five (1990 to 2014) ====
[[File:John Houghton High Wycombe 20050226.jpg|thumb|right|[[IPCC Third Assessment Report]] Working Group I Co-chair Sir [[John T. Houghton]] showing a figure that was included in the "Summary for Policymakers" of that report ("[[hockey stick graph (global temperature)|hockey stick graph]]") at a climate conference in 2005]]
* The IPCC's [[IPCC First Assessment Report|First Assessment Report]] (FAR) appeared in 1990. The report gave a broad overview of climate change science. It discussed uncertainties and provided evidence of warming. The authors said they are certain that greenhouse gases are increasing in the atmosphere because of human activity. This is resulting in more warming of the [[Earth]]'s surface.<ref>{{Cite web |title=FAR Climate Change: Scientific Assessment of Climate Change — IPCC |url=https://www.ipcc.ch/report/ar1/wg1/ |access-date=2022-11-10}}</ref><ref>{{Cite web |date=1990 |title=Climate Change: The IPCC Scientific Assessment: Policymaker Summary - Executive Summary |url=https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_I_spm.pdf |website=ipcc.ch}}</ref> The report led to the establishment of the [[United Nations Framework Convention on Climate Change]] (UNFCCC).<ref name="UCS IPCC Who are they?" />
* The [[IPCC Second Assessment Report|Second Assessment Report]] (SAR), was published in 1995. It strengthened the findings of the First Assessment Report. The evidence suggests that there is a discernible human influence on the global climate, it said.<ref>{{Cite web |date=1995 |title=Climate Change 1995: Second Assessment Synthesis |url=https://www.ipcc.ch/site/assets/uploads/2018/05/2nd-assessment-en-1.pdf |website=ipcc.ch}}</ref> The Second Assessment Report provided important material for the negotiations leading to the UNFCCC's [[Kyoto Protocol]].<ref>{{Cite web |date=2012 |title=Convention on Biological Diversity: Working Relationship Between the United Nations Framework Convention on Climate Change and the Intergovernmental Panel on Climate Change |url=https://www.cbd.int/doc/meetings/cop/cop-11/information/cop-11-inf-14-en.doc}}</ref>
* The [[IPCC Third Assessment Report|Third Assessment Report]] (TAR) was completed in 2001. It found more evidence that most of the global warming seen over the previous 50 years was due to human activity.<ref>{{Cite web |date=1995 |title=Climate Change 1995: Synthesis Report |url=https://www.ipcc.ch/site/assets/uploads/2018/05/SYR_TAR_full_report.pdf |website=ipcc.ch}}</ref> The report includes a graph reconstructing global temperature since the year 1000. The sharp rise in temperature in recent years gave it the name "[[Hockey stick graph (global temperature)|hockey stick]]". This became a powerful image of how temperature is soaring with climate change. The report also shows how adaptation to the effects of climate change can reduce some of its ill effects.
* The IPCC's [[IPCC Fourth Assessment Report|Fourth Assessment Report]] (AR4) was published in 2007. It gives much greater certainty about climate change. It states: "Warming of the climate system is unequivocal..."<ref>{{Cite web |title=Climate Change 2007: The Physical Science Basis - Summary for Policymakers |url=https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-spm-1.pdf |website=ipcc.ch}}</ref> The report helped make people around the world aware of climate change. The IPCC shared the [[Nobel Peace Prize]] in the year of the report's publication for this work (see below).
* The [[IPCC Fifth Assessment Report|Fifth Assessment Report]] (AR5) was published in 2013 and 2014. This report again stated the fact of climate change. It warned of the dangerous risks. And it emphasizes how the world can counter climate change. Three key findings were for example: Firstly, human influence on the [[climate system]] is clear. Secondly, the more we disrupt our climate, the more we risk severe, pervasive, and irreversible [[Effects of climate change|impacts]]. And thirdly, we have the means to limit climate change and build a more prosperous, [[sustainable]] future.<ref>{{Cite web |title=IPCC 5th Assessment Report published |url=https://ieaghg.org/conferences/2-uncategorised/511-ipcc-5th-assessment-report-published |access-date=2022-11-10 |website=ieaghg.org |archive-date=10 November 2022 |archive-url=https://web.archive.org/web/20221110173512/https://ieaghg.org/conferences/2-uncategorised/511-ipcc-5th-assessment-report-published }}</ref> The report's findings were the scientific foundation of the UNFCCC's 2015 [[Paris Agreement]].<ref>{{Cite web |title=IPCC (AR5) report - the foundation for the Paris Agreement |url=https://www.ed.ac.uk/geosciences/research/impact/ipcc/ar5-report |access-date=2022-11-10 |website=The University of Edinburgh |date=7 November 2021 |language=en}}</ref>

====Sixth assessment report (2021/2022)====
The IPCC's most recent report is the [[IPCC Sixth Assessment Report|Sixth Assessment Report (AR6)]]. The first three installments of AR6 appeared in 2021 and 2022. The final synthesis report was completed in March 2023.

The IPCC published the Working Group I report, ''Climate Change 2021: The Physical Science Basis'', in August 2021.<ref name=":6" /> It confirms that the climate is already changing in every region. Many of these changes have not been seen in thousands of years. Many of them such as [[Sea level rise|sea-level rise]] are irreversible over hundreds of thousands of years. Strong reductions in greenhouse gas emissions would limit climate change. But it could take 20–30 years for the climate to stabilize.<ref>{{Cite web |date=9 August 2021 |title=IPCC Press Release - Working Group I contribution to Sixth Assessment Report |url=https://www.ipcc.ch/site/assets/uploads/2021/08/IPCC_WGI-AR6-Press-Release_en.pdf |website=ipcc.ch}}</ref> This report attracted enormous media and public attention. U.N. Secretary-General [[António Guterres]] described it as "code red for humanity".<ref>{{Cite web |date=9 August 2021 |title=IPCC report: 'Code red' for human-driven global heating, warns UN chief |url=https://news.un.org/en/story/2021/08/1097362 |website=UN News}}</ref>

The IPCC published the Working Group II report, ''Climate Change 2022: Impacts, Adaptation and Vulnerability'', in February 2022.<ref>IPCC, 2022: ''[https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/ Climate Change 2022: Impacts, Adaptation, and Vulnerability].'' Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press. Cambridge University Press, Cambridge, UK and New York, New York, US, 3056 pp., doi:10.1017/9781009325844.</ref> Climate change due to human activities is already affecting the lives of billions of people, it said. It is disrupting nature. The world faces unavoidable hazards over the next two decades even with global warming of 1.5&nbsp;°C, it said.<ref>{{Cite web |title=Press release |url=https://www.ipcc.ch/report/ar6/wg2/resources/press/press-release/ |access-date=2022-11-11 |website=www.ipcc.ch |language=en}}</ref>

The IPCC published the Working Group III report, ''Climate Change 2022: Mitigation of Climate Change'', in April 2022.<ref>IPCC, 2022'': [https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/ Climate Change 2022: Mitigation of Climate Change]. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change'' [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, New York, US. doi: 10.1017/9781009157926</ref> It will be impossible to limit warming to 1.5&nbsp;°C without immediate and deep cuts in greenhouse gas emissions. It is still possible to halve emissions by 2050, it said.<ref>{{Cite web |title=Press release - The evidence is clear: the time for action is now. We can halve emissions by 2030. |date=4 April 2022 |url=https://www.ipcc.ch/report/ar6/wg3/resources/press/press-release/ |access-date=2022-11-11 |website=IPCC  |language=en}}</ref>

== Other reports ==

===Special reports===
The IPCC also publishes other types of reports. It produces Special Reports on topics proposed by governments or observer organizations. Between 1994 and 2019 the IPCC published 14 special reports. Now usually more than one working group cooperates to produce a special report. The preparation and approval process is the same as for assessment reports.<ref name="Appendix A to the Principles Governing IPCC Work" />

==== Special reports in 2011 ====
During the fifth assessment cycle, the IPCC produced two special reports. It completed the Special Report on Renewable Energy Sources and Climate Change Mitigation in 2011. Working Group III prepared this report. The report examined options to use different types of renewable energy to replace fossil fuels. The report noted that the cost of most renewable technologies had fallen. It was likely to fall even more with further advances in technology. It said renewables could increase access to energy. The report reviewed 164 scenarios that examine how renewables could help stop climate change. In more than half of these scenarios, renewables would contribute more than 27% of the primary energy supply in the mid-century. This would be more than double the 13% share in 2008. In the scenarios with the highest shares for renewable energy, it will contribute 77% by 2050.<ref>{{Cite web |title=Renewable Energy Sources and Climate Change Mitigation |website=IPCC |url=https://www.ipcc.ch/report/renewable-energy-sources-and-climate-change-mitigation/ |access-date=2022-11-16}}</ref>

Later in 2011, the IPCC released the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. This was a collaboration between Working Groups I and II. It was the first time two IPCC working groups worked together on a special report. The report shows how climate change has contributed to changes in extreme weather. And it shows how policies to avoid and prepare for extreme weather events can reduce their impact. In the same way, policies to respond to events and recover from them can make societies more resilient.<ref>{{Cite web |title=Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation |website=IPCC |url=https://www.ipcc.ch/report/managing-the-risks-of-extreme-events-and-disasters-to-advance-climate-change-adaptation/ |access-date=2022-11-16}}</ref><ref>{{Cite web |date=28 March 2012 |title=PRESS RELEASE: IPCC releases full report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) |url=https://www.ipcc.ch/site/assets/uploads/2018/06/srex_press_release.pdf |website=IPCC }}</ref>

==== Special reports 2018–2019 ====
During the sixth assessment cycle, the IPCC produced three special reports. This made it the most ambitious cycle in IPCC history. The [[United Nations Framework Convention on Climate Change|UNFCCC]] set a goal of keeping global warming well below {{Convert|2|°C|abbr=on}} while trying to hold it at {{Convert|1.5|°C|abbr=on}}, when it reached the [[Paris Agreement]] at [[2015 United Nations Climate Change Conference|COP21]] in 2015. But at the time there was little understanding of what warming of 1.5&nbsp;°C meant. There was little scientific research explaining how the impacts of 1.5&nbsp;°C would differ from 2&nbsp;°C. And there was little understanding about how to keep warming to 1.5&nbsp;°C. So the UNFCCC invited the IPCC to prepare a report on global warming of 1.5&nbsp;°C. The IPCC subsequently released the [[Special Report on Global Warming of 1.5 °C]] (SR15) in 2018.<ref>{{Cite web |title=Global Warming of 1.5 °C — |url=https://www.ipcc.ch/sr15/ |website=IPCC |access-date=2022-11-17}}</ref> The report showed that it was possible to keep warming below 1.5&nbsp;°C during the 21st century. But this would mean deep cuts in emissions. It would also mean rapid, far-reaching changes in all aspects of society.<ref>{{Cite web |date=8 October 2018 |title=IPCC Press Release: Summary for Policymakers of IPCC Special Report on Global Warming of 1.5 °C approved by governments |url=https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/pr_181008_P48_spm_en.pdf |website=IPCC}}</ref> The report showed warming of 2&nbsp;°C would have much more severe impacts than 1.5&nbsp;°C. In other words: every bit of warming matters. SR15 had an unprecedented impact on an IPCC report in the media and with the public.<ref name=":4" /> It put the 1.5&nbsp;°C target at the centre of [[climate activism]].<ref>{{Cite news |date=21 January 2020 |title=Greta Thunberg tells leaders at Davos to heed global heating science |work=The Guardian |url=https://www.theguardian.com/business/2020/jan/21/greta-thunberg-calls-on-world-leaders-to-heed-global-heating-science-davos}}</ref>

In 2019 the IPCC released two more special reports that examine different parts of the climate system. The [[Special Report on Climate Change and Land]] examined how the way we use land affects the climate. It looked at emissions from activities such as farming and forestry rather than from energy and transport. It also looked at how climate change is affecting land. All three IPCC working groups and its Task Force on National Greenhouse Gas Inventories collaborated on the report. The report found that climate change is adding to the pressures we are putting on the land we use to live on and grow our food.<ref>{{Cite web |title=Special Report on Climate Change and Land — IPCC site |url=https://www.ipcc.ch/srccl/ |access-date=2022-11-17}}</ref> It will only be possible to keep warming well below 2&nbsp;°C if we reduce emissions from all sectors including land and food, it said.<ref>{{Cite web |title=Land is a Critical Resource, IPCC report says — IPCC |url=https://www.ipcc.ch/2019/08/08/land-is-a-critical-resource_srccl/ |access-date=2022-11-17}}</ref>

The [[Special Report on the Ocean and Cryosphere in a Changing Climate]] examined how the ocean and frozen parts of the planet interact with climate change. (The [[cryosphere]] includes frozen systems such as ice sheets, glaciers, and permafrost.) IPCC Working Groups I and II prepared the report. The report highlighted the need to tackle unprecedented changes in the ocean and cryosphere.<ref>{{Cite web |title=Special Report on the Ocean and Cryosphere in a Changing Climate — |url=https://www.ipcc.ch/srocc/ |access-date=2022-11-17}}</ref> It also showed how [[Climate change adaptation|adaptation]] could help [[sustainable development]].

===Methodology Reports===
The IPCC has a National Greenhouse Gas Inventories Programme. It develops methodologies and software for countries to report their [[greenhouse gas]] emissions. The IPCC's Task Force on National Greenhouse Gas Inventories (TFI) has managed the program since 1998.<ref name=":5" /> Japan's Institute for Global Environmental Strategies<ref>{{Cite web |title=Institute for Global Environmental Strategies (IGES) |url=https://www.iges.or.jp/en |access-date=2022-11-17 |website=IGES |language=en}}</ref> hosts the TFI's Technical Support Unit.

==== Revised 1996 IPCC Guidelines ====
The IPCC released its first Methodology Report, the IPCC ''Guidelines for National Greenhouse Gas Inventories'', in 1994. The ''Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories'' updated this report.<ref>{{Cite web |title=Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories — IPCC |url=https://www.ipcc.ch/report/revised-1996-ipcc-guidelines-for-national-greenhouse-gas-inventories/ |access-date=2022-11-17}}</ref> Two "good practice reports" complete these guidelines. These are the ''Good Practice Guidance'' ''and Uncertainty Management in National Greenhouse Gas Inventories'' and ''Good Practice Guidance for Land Use, Land-Use Change and Forestry''. Parties to the [[United Nations Framework Convention on Climate Change|UNFCCC]] and its [[Kyoto Protocol]] use the 1996 guidelines and two good practice reports for their annual submissions of inventories.

==== 2006 IPCC Guidelines ====
The ''2006 IPCC Guidelines for National Greenhouse Gas Inventories'' further update these methodologies.<ref>{{Cite web |title=2006 IPCC Guidelines for National Greenhouse Gas Inventories — IPCC |url=https://www.ipcc.ch/report/2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/ |access-date=2022-11-17}}</ref> They include a large number of "default emission factors". These are factors to estimate the amount of emissions for an activity. The IPCC prepared this new version of the guidelines at the request of the UNFCCC.<ref>{{Cite web |title=Reporting requirements |url=https://unfccc.int/process-and-meetings/transparency-and-reporting/reporting-and-review-under-the-convention/greenhouse-gas-inventories-annex-i-parties/reporting-requirements |access-date=2022-11-17 |website=unfccc.int}}</ref> The UNFCCC accepted them for use at its [[2013 United Nations Climate Change Conference|2013 Climate Change Conference]], COP19, in Warsaw. The IPCC added further material in its ''2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories''.<ref>{{Cite web |title=2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories — IPCC |url=https://www.ipcc.ch/report/2019-refinement-to-the-2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/ |access-date=2022-11-17}}</ref>

The TFI has started preparations for a methodology report on short-lived climate forcers (SLCFs).<ref>{{Cite web |date=13 September 2022 |title=PROGRESS REPORTS: Task Force on National Greenhouse Gas Inventories |url=https://apps.ipcc.ch/eventmanager/documents/75/140920220535-INF.%205,%20Rev.1%20%20Progress%20Report%20TFI.pdf |website=ipcc.ch}}</ref><ref>{{Cite web |title=Short-Lived Climate Pollutants |url=https://www.worldbank.org/en/topic/climatechange/brief/short-lived-climate-pollutants |access-date=2022-11-17 |website=World Bank |language=en}}</ref> It will complete this report in the next assessment cycle, the seventh.

== Challenges and controversies ==
IPCC reports also attract criticism. Criticisms come from both people who say the reports exaggerate the risks and people who say they understate them.<ref name=":2">{{Cite web |last=Scherer |first=Glenn |date=2012-12-06 |title=Climate Science Predictions Prove Too Conservative |url=https://www.scientificamerican.com/article/climate-science-predictions-prove-too-conservative/ |access-date=2022-10-27 |website=Scientific American |language=en}}</ref> The IPCC consensus approach has faced internal and external challenges.<ref name="ess">[https://link.springer.com/article/10.1007/s10584-011-0176-8/fulltext.html#Sec7 Evaluation, characterization, and communication of uncertainty by the intergovernmental panel on climate change—an introductory essay. Climatic Change An Interdisciplinary, International Journal Devoted to the Description, Causes and Implications of Climatic Change, Gary Yohe and Michael Oppenheimer] 2011</ref><ref name="MO">{{cite journal |last1=Oppenheimer |first1=Michael |author1-link=Michael Oppenheimer |last2=O'Neill |first2=Brian C. |last3=Webster |first3=Mort |last4=Agrawal |first4=Shardul |year=2007 |title=Climate Change, The Limits of Consensus |journal=[[Science (magazine)|Science]] |volume=317 |issue=5844 |pages=1505–1506 |doi=10.1126/science.1144831 |pmid=17872430 |s2cid=129837694}}</ref>

===Conservative nature of IPCC reports===
Some critics have argued that IPCC reports tend to be too conservative in their assessments of climate risk. In 2012, it was reported that the IPCC has been criticized by some scientists, who argue that the reports consistently underestimate the pace and impacts of global warming.<ref name=":2" /> As a result, they believe this leads to findings that are the "lowest common denominator".<ref>{{cite journal|last=McKibben|first=Bill |date=15 March 2007 |title=Warning on Warming|journal=The New York Review of Books|volume=54|issue=4|page=18|url=http://www.nybooks.com/articles/19981|access-date=21 February 2010|bibcode=2004Natur.427..197S|doi=10.1038/427197a|doi-access=free}}</ref> {{Clarify|reason=The use of the phrase "lowest common denominator" is somewhat ambiguous|date=April 2023}} Similar claims have also been made by scientists who found that for the last several assessment reports, the focus of the IPCC reports skewed more and more towards lower temperatures, especially 1.5°C.<ref>{{cite journal |last1=Jehn |first1=Florian U. |last2=Kemp |first2=Luke |last3=Ilin |first3=Ekaterina |last4=Funk |first4=Christoph |last5=Wang |first5=Jason R. |last6=Breuer |first6=Lutz |title=Focus of the IPCC Assessment Reports Has Shifted to Lower Temperatures |journal=Earth's Future |date=May 2022 |volume=10 |issue=5 |article-number=e2022EF002876 |doi=10.1029/2022EF002876|doi-access=free |bibcode=2022EaFut..1002876J }}</ref> Temperatures above 2°C however, have seen much less attention, even though they seem more likely given current emission trajectories.<ref>{{cite journal |last1=Jehn |first1=Florian U |last2=Schneider |first2=Marie |last3=Wang |first3=Jason R |last4=Kemp |first4=Luke |last5=Breuer |first5=Lutz |title=Betting on the best case: higher end warming is underrepresented in research |journal=Environmental Research Letters |date=1 August 2021 |volume=16 |issue=8 |page=084036 |doi=10.1088/1748-9326/ac13ef|doi-access=free |bibcode=2021ERL....16h4036J }}</ref> 

David Biello, writing in the [[Scientific American]], argues that, because of the need to secure consensus among governmental representatives, the IPCC reports give conservative estimates of the likely extent and effects of global warming.<ref>{{cite journal |author=Biello D |date=April 2007 |title=Conservative Climate |journal=Scientific American |volume=296 |issue=4 |pages=16–19 |bibcode=2007SciAm.296d..16B |doi=10.1038/scientificamerican0407-16 |pmid=17479619}}</ref> ''[[Science (journal)|Science]]'' editor Brooks Hanson states in a 2010 editorial: "The IPCC reports have underestimated the pace of climate change while overestimating societies' abilities to curb greenhouse gas emissions."<ref name="AAAS">{{cite journal |last=Hanson |first=Brooks |date=7 May 2010 |title=Stepping Back; Moving Forward |journal=[[Science (journal)|Science]] |volume=328 |issue=5979 |page=667 |bibcode=2010Sci...328..667H |doi=10.1126/science.1190790 |pmid=20448154 |doi-access=free}}</ref>

Climate scientist [[James E. Hansen]] argues that the IPCC's conservativeness seriously underestimates the risk of [[Sea level rise|sea-level rise]] on the order of meters—enough to inundate many low-lying areas, such as the southern third of Florida.<ref>{{cite journal |author=Hansen JE |date=April–June 2007 |title=Scientific reticence and sea level rise |journal=Environmental Research Letters |volume=2 |issue=2 |article-number=024002 |arxiv=physics/0703220 |bibcode=2007ERL.....2b4002H |doi=10.1088/1748-9326/2/2/024002 |s2cid=59929933}}</ref> In January 2024, he told the Guardian, "We are now in the process of moving into the 1.5C world." He added that "passing through the 1.5C world is a significant milestone because it shows that the story being told by the United Nations, with the acquiescence of its scientific advisory body, the IPCC, is a load of bullshit."<ref>[https://www.theguardian.com/environment/2024/jan/08/global-temperature-over-1-5-c-climate-change Global heating will pass 1.5C threshold this year, top ex-Nasa scientist says], Guardian, 8 January 2023</ref>

[[Roger A. Pielke|Roger A. Pielke Sr.]] has also stated "Humans are significantly altering the global climate, but in a variety of diverse ways beyond the radiative effect of carbon dioxide. The IPCC assessments have been too conservative in recognizing the importance of these human climate forcings as they alter regional and global climate."<ref>{{cite web |title=Climate Science: Main Conclusions |url=http://climatesci.org/main-conclusions/ |archive-url=https://web.archive.org/web/20081211205600/http://climatesci.org/main-conclusions/ |archive-date=11 December 2008 |access-date=11 December 2008}}</ref>

[[Stefan Rahmstorf]], a professor of physics and oceanography at [[University of Potsdam]], argued in 2007 that the IPCC's tendency to make conservative risk assessments had benefits. Rahmstorf argued that "In a way, it is one of the strengths of the IPCC to be very conservative and cautious and not overstate any climate change risk".<ref>{{cite web|title=Climate change: The scientific basis |date=5 February 2007 |access-date=24 July 2007 |url=http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20070129/ipcc_faq_070129/20070129?hub=SciTech |archive-url=https://web.archive.org/web/20070205051907/http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20070129/ipcc_faq_070129/20070129?hub=SciTech |archive-date=5 February 2007 |publisher=[[CTV Television Network]]}}</ref> IPCC reports aim to inform policymakers about the state of knowledge on climate change. They do this by assessing the findings of the thousands of scientific papers available on the subject at a given time. Individual publications may have different conclusions from IPCC reports. This includes those appearing just after the release of an IPCC report. This can lead to criticism that the IPCC is either alarmist or conservative. New findings must wait for the next assessment for consideration.<ref>{{Cite web |title=New climate report actually understates threat, some researchers argue |url=https://www.science.org/content/article/new-climate-report-actually-understates-threat-some-researchers-argue |access-date=2022-10-28 |website=www.science.org |language=en}}</ref><ref>{{Cite web |title=How the IPCC is more likely to underestimate the climate response |url=https://skepticalscience.com/print.php?r=51 |access-date=2022-10-28 |website=skepticalscience.com}}</ref>

=== Potential industry and political influence ===
A memo by [[ExxonMobil]] to the [[Presidency of George W. Bush|Bush administration]] in the United States in 2002 was an example of possible political influence on the IPCC. The memo led to strong Bush administration lobbying to oust [[Robert Watson (scientist)|Robert Watson]], a climate scientist, as IPCC chair. They sought to replace him with [[Rajendra K. Pachauri|Rajendra Pachauri]]. Many considered Pachauri at the time as more mild-mannered and industry-friendly.<ref name = "Common Dreams">{{cite news | title=US and Oil Lobby Oust Climate Change Scientist | date=20 April 2002 | access-date=24 July 2007 | first=Julian | last=Borger | url=https://www.theguardian.com/bush/story/0,7369,687650,00.html | newspaper=Guardian | location=London}}</ref>

Governments form the membership of the IPCC. They are the prime audience for IPCC reports. IPCC rules give them a formal role in the scoping, preparation, and approval of reports.<ref>{{Cite web |title=Preparing Reports — IPCC |url=https://www.ipcc.ch/about/preparingreports/ |access-date=2022-10-28}}</ref> For instance governments take part in the review process and work with authors to approve the Summary for Policymakers of reports. But some activists have argued that governments abuse this role to influence the outcome of reports.<ref>{{Cite web |title=Leaks show attempts to water down UN climate report – DW – 10/21/2021 |url=https://www.dw.com/en/leaks-show-attempts-to-water-down-un-climate-report-greenpeace-says/a-59570391 |access-date=2022-10-28 |website=dw.com |language=en}}</ref>

In 2023, it was reported that pressure from [[Brazil]] and [[Argentina]], two countries with large beef industries, caused the IPCC to abandon text recommending the adoption of plant-based diets. An earlier draft of the report, which noted "plant-based diets can reduce GHG emissions by up to 50% compared to the average emission-intensive Western diet", was leaked online in March 2023.<ref>{{Cite web |last=Almendral |first=Aurora |date=2023-03-24 |title=The meat industry blocked the IPCC's attempt to recommend a plant-based diet |url=https://qz.com/ipcc-report-on-climate-change-meat-industry-1850261179 |access-date=2023-03-29 |website=Quartz |language=en}}</ref>

=== Controversy and review after Fourth Assessment Report in 2007 ===
The IPCC came under unprecedented media scrutiny in 2009 in the run-up to the [[2009 United Nations Climate Change Conference|Copenhagen climate conference]]. This "[[Climatic Research Unit email controversy]]" involved the leak of emails from climate scientists. Many of these scientists were authors of the [[IPCC Fourth Assessment Report|Fourth Assessment Report]] which came out in 2007. The discovery of an error in this report that the Himalayan glaciers would melt by 2035 put the IPCC under further pressure.<ref>{{Cite web |last=Pearce |first=Fred |date=21 January 2010 |title=Climate chief admits error over Himalayan glaciers |url=https://www.newscientist.com/article/dn18420-climate-chief-admits-error-over-himalayan-glaciers/ |access-date=2022-10-27 |website=New Scientist |language=en-US}}</ref> Scientific bodies upheld the general findings of the Fourth Assessment Report and the IPCC's approach.<ref>{{Cite web |last=ICSU |date=2011-01-27 |title=ICSU releases statement on the controversy around the 4th IPCC Assessment |url=https://council.science/current/news/icsu-releases-statement-on-the-controversy-around-the-4th-ipcc-assessment/ |access-date=2022-10-27 |website=International Science Council |language=en-US}}</ref><ref>{{Cite web |last=PBL |date=2010-07-06 |title=Assessing an IPCC assessment. An analysis of statements on projected regional impacts in the 2007 report |url=https://www.pbl.nl/en/publications/Assessing-an-IPCC-assessment.-An-analysis-of-statements-on-projected-regional-impacts-in-the-2007-report |access-date=2022-10-27 |website=PBL Netherlands Environmental Assessment Agency |language=en |archive-date=20 January 2023 |archive-url=https://web.archive.org/web/20230120151517/https://www.pbl.nl/en/publications/Assessing-an-IPCC-assessment.-An-analysis-of-statements-on-projected-regional-impacts-in-the-2007-report }}</ref> But many people thought the IPCC should review the way it works.<ref name=":1">{{cite news |last=Black |first=Richard |date=10 March 2010 |title=Scientists to review climate body |work=BBC News |url=https://news.bbc.co.uk/2/hi/science/nature/8561004.stm |access-date=4 April 2010}}</ref>

==== InterAcademy Council review in 2010 ====
Public debate after the publication of AR4 in 2009 put the IPCC under scrutiny, with controversies over alleged bias and inaccuracy in its reports. In 2010, this prompted U.N. Secretary-General [[Ban Ki-moon]] and IPCC chair [[Rajendra K. Pachauri]] to request that the [[InterAcademy Panel|InterAcademy Council]] (IAC) review the IPCC and recommend ways to strengthen its processes and procedures for the preparation of AR5. The IAC report made recommendations to fortify IPCC's management structure, to further develop its conflict-of-interest policy, to strengthen the review process, to clarify the guidelines on the use of so-called [[Grey literature|gray literature]], to ensure consistency in the use of probabilities for the likelihood of outcomes, and to improve its communications strategy, especially regarding transparency and rapidity of response.<ref>{{cite web |title=InterAcademy Council Report Recommends Fundamental Reform of IPCC Management Structure |url=http://reviewipcc.interacademycouncil.net/ReportNewsRelease.html |archive-url=https://web.archive.org/web/20130806073912/http://reviewipcc.interacademycouncil.net/ReportNewsRelease.html |archive-date=2013-08-06 |access-date=30 August 2013 |publisher=InterAcademy Council}}</ref>

The United Nations Secretary-General and the Chair of the IPCC asked the InterAcademy Council (IAC) in March 2010 to review the IPCC's processes for preparing its reports.<ref name=":1" /><ref name="IAC report">{{Cite web|url=https://www.interacademies.org/news/interacademy-council-report-recommends-fundamental-reform-ipcc-management-structure|title=InterAcademy Council Report Recommends Fundamental Reform of IPCC Management Structure|first=the InterAcademy|last=Partnership (IAP)|website=www.interacademies.org|date=30 August 2011 }}</ref> The IAC panel, chaired by [[Harold Tafler Shapiro]], released its report on 1 September 2010.<ref name=":0">{{Cite journal |last=Tollefson |first=J. |year=2010 |title=Climate panel must adapt to survive |journal=Nature |volume=467 |issue=7311 |page=14 |doi=10.1038/467014a |pmid=20811426 |doi-access=free}}</ref> The IAC panel made seven formal recommendations for improving the IPCC's assessment process. The IPCC implemented most of the review's recommendations by 2012. One of these was the introduction of a protocol to handle errors in reports.<ref name="Appendix A to the Principles Governing IPCC Work"/><ref>{{Cite web |date=October 2013 |orig-date=May 2011 |title=Annex 3 - IPCC Protocol for Addressing Possible Errors in IPCC Assessment Reports, Synthesis Reports, Special Reports and Methodology Reports |url=https://www.ipcc.ch/site/assets/uploads/2018/09/ipcc_error_protocol_en.pdf |website=IPCC}}</ref> Other recommendations included strengthening the science-review process and improving communications. However, the IPCC did not adopt the proposal to appoint a full-time executive secretary.<ref name=":0" /><ref>{{Cite web |last=IPCC - Intergovernmental Panel on Climate Change |title=REVIEW OF IPCC PROCESSES AND PROCEDURES |url=https://archive.ipcc.ch/organization/organization_review.shtml |access-date=2022-10-27 |website=archive.ipcc.ch}}</ref>

=== Issues with consensual approach ===

[[Michael Oppenheimer]], a long-time participant in the IPCC, has said the IPCC consensus approach has some limitations. Oppenheimer, a coordinating lead author of the [[IPCC Fifth Assessment Report|Fifth Assessment Report]], called for concurring, smaller assessments of special problems instead of the large-scale approach of previous IPCC assessments.<ref name="MO" /> Others see "mixed blessings" in the drive for consensus within the IPCC. They suggest including dissenting or minority positions.<ref name=hu>[http://www.csap.cam.ac.uk/media/uploads/files/1/fdsaw.pdf Lessons from the IPCC: do scientific assessments need to be consensual to be authoritative?] [[Mike Hulme]], in (eds.) Doubelday, R. and Willesden, J. March 2013, pp, 142 ff</ref> Others suggest improving statements about uncertainties.<ref name=nocon>[http://judithcurry.com/2013/04/22/do-scientific-assessments-need-to-be-consensual-to-be-authoritative/ Do scientific assessments need to be consensual to be authoritative?] Curry, JA and PJ Webster, 2012: Climate change: no consensus on consensus. CAB Reviews, in press, 2012</ref><ref>{{cite journal | url = http://www.nature.com/news/2010/101101/full/news.2010.577.html | title=Climate heretic: Judith Curry turns on her colleagues | journal=Nature | date=1 November 2010 | access-date=22 December 2010| doi=10.1038/news.2010.577 | last1=Lemonick | first1=Michael D. | url-access=subscription }}</ref>

=== Criticism by experts involved with the IPCC process ===
Some of the criticism has originated from experts invited by the IPCC to submit reports or serve on its panels. For example, [[John Christy]], a contributing author who works at the [[University of Alabama in Huntsville]], explained in 2007 the difficulties of establishing scientific consensus on the precise extent of human action on climate change. "Contributing authors essentially are asked to contribute a little text at the beginning and to review the first two drafts. We have no control over editing decisions. Even less influence is granted to the 2,000 or so reviewers. Thus, to say that 800 contributing authors or 2,000 reviewers reached consensus on anything describes a situation that is not reality", he wrote.<ref name="Christy-2007">{{cite web|url=http://www.nsstc.uah.edu/atmos/christy/ChristyJR_07EC_subEAQ_written.pdf|archive-url=https://web.archive.org/web/20071128074622/http://www.nsstc.uah.edu/atmos/christy/ChristyJR_07EC_subEAQ_written.pdf |archive-date=2007-11-28|title=Written testimony of John R. Christy Ph.D. before House Committee on Energy and Commerce on March 7, 2007|access-date=29 December 2008}}</ref> [[Christopher Landsea]], a hurricane researcher, said of "the part of the IPCC to which my expertise is relevant" that "I personally cannot in good faith continue to contribute to a process that I view as both being motivated by pre-conceived agendas and being scientifically unsound,"<ref>{{cite web |title=An Open Letter to the Community from Chris Landsea |url=http://www.lavoisier.com.au/papers/articles/landsea.html |archive-url=https://web.archive.org/web/20070218131946/http://www.lavoisier.com.au/papers/articles/landsea.html |archive-date=18 February 2007 |access-date=28 April 2007}}</ref> because of comments made at a press conference by [[Kevin Trenberth]] of which Landsea disapproved. Trenberth said "Landsea's comments were not correct";<ref name="Colorodo.edu-Hurricanes-Prometheus">{{cite web |date=14 February 2007 |title=Prometheus: Final Chapter, Hurricanes and IPCC, Book IV Archives |url=http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001105final_chapter_hurri.html |access-date=29 August 2010 |publisher=Sciencepolicy.colorado.edu}}</ref> the IPCC replied "individual scientists can do what they wish in their own rights, as long as they are not saying anything on behalf of the IPCC".<ref>{{cite news |date=21 October 2004 |title=Hurricanes and Global Warming for IPCC |agency=Reuters |location=Washington |url=http://sciencepolicy.colorado.edu/prometheus/archives/ipcc-correspondence.pdf |access-date=30 December 2008}}</ref>

== Endorsements and awards ==

=== Endorsements from scientific bodies ===
IPCC reports are the benchmark for [[Climate Science|climate science]].<ref>{{Citation |last1=Paglia |first1=Eric |title=The Intergovernmental Panel on Climate Change: Guardian of Climate Science |date=2021 |work=Guardians of Public Value |pages=295–321 |editor-last=Boin |editor-first=Arjen |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-51701-4_12 |isbn=978-3-030-51700-7 |last2=Parker |first2=Charles |s2cid=228892648 |editor2-last=Fahy |editor2-first=Lauren A. |editor3-last='t Hart |editor3-first=Paul|doi-access=free }}</ref> There is widespread support for the IPCC in the [[scientific community]]. Publications by other scientific bodies and experts show this.<ref>* {{cite web |title=Scientists Send Letter to Congress and Federal Agencies Supporting IPCC |url=http://www.agu.org/sci_pol/events/2010-03-12_ScientistsLetter_Congress.shtml |archive-url=https://web.archive.org/web/20111024142639/http://www.agu.org/sci_pol/events/2010-03-12_ScientistsLetter_Congress.shtml |archive-date=24 October 2011 |access-date=28 March 2011 |publisher=American Geophysical Union}}
* {{cite web |author=Yohe, G.W. |display-authors=etal |title=An Open Letter from Scientists in the United States on the Intergovernmental Panel on Climate Change and Errors Contained in the Fourth Assessment Report: Climate Change 2007 |url=http://www.openletterfromscientists.com/ |archive-url=https://web.archive.org/web/20100315155535/http://www.openletterfromscientists.com/ |archive-date=15 March 2010}}. Note: According to Yohe ''et al.'' (2010), more than 250 scientists have signed the statement.
</ref><ref name="2001 science academies statement">{{citation |others=Joint statement by 16 national science academies |title=The Science of Climate Change |date=17 May 2001 |url=http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2001/10029.pdf |archive-url=https://web.archive.org/web/20150419074652/https://royalsociety.org/~/media/Royal_Society_Content/policy/publications/2001/10029.pdf |location=London |publisher=Royal Society |isbn=978-0-85403-558-8 |archive-date=19 April 2015}}</ref> Many scientific bodies have issued official statements that endorse the findings of the IPCC. For example:
* For the [[Third Assessment Report]] in 2001 endorsements came from the [[Canadian Foundation for Climate and Atmospheric Sciences]],<ref name="cfcas tar endorsement">{{Cite web|url=http://www.cfcas.org/LettertoPM19apr06e.pdf|archive-url=https://web.archive.org/web/20100821222002/http://www.cfcas.org/LettertoPM19apr06e.pdf|title=CFCAS Letter to PM, November 25, 2005|archive-date=21 August 2010|access-date=9 August 2019}}</ref> [[United States National Research Council]]<ref>{{Cite book |url=https://nap.nationalacademies.org/catalog/10139/climate-change-science-an-analysis-of-some-key-questions |title=Climate Change Science: An Analysis of Some Key Questions |date=2001 |publisher=National Academies Press |isbn=978-0-309-07574-9 |location=Washington, D.C. |chapter=Summary |doi=10.17226/10139 |chapter-url=https://nap.nationalacademies.org/read/10139/chapter/2}}</ref> and [[European Geosciences Union]].<ref>{{Cite web|url=https://cdn.egu.eu/media/filer_public/10/78/10784a01-d4e6-4093-9c8f-8de0ffc3d13b/climate_change.pdf|title=European Geosciences Union (EGU): Position Statements|access-date=1 November 2022|archive-date=10 June 2023|archive-url=https://web.archive.org/web/20230610033148/https://cdn.egu.eu/media/filer_public/10/78/10784a01-d4e6-4093-9c8f-8de0ffc3d13b/climate_change.pdf}}</ref>
* For the [[IPCC Fourth Assessment Report|Fourth Assessment Report]] in 2007 endorsements came from the [[International Council for Science]] (ICSU),<ref>{{Cite web |last=admin |date=2011-01-27 |title=ICSU releases statement on the controversy around the 4th IPCC Assessment |url=https://council.science/current/news/icsu-releases-statement-on-the-controversy-around-the-4th-ipcc-assessment/ |access-date=2022-11-01 |website=International Science Council |language=en-US}}</ref> and the [[Network of African Science Academies]].<ref name="autogenerated1">{{cite web |year=2007 |title=Joint statement by the Network of African Science Academies (NASAC) |url=http://www.interacademies.net/Object.File/Master/4/825/NASAC%20G8%20statement%2007%20-%20low%20res.pdf |archive-url=https://web.archive.org/web/20080910214452/http://www.interacademies.net/Object.File/Master/4/825/NASAC%20G8%20statement%2007%20-%20low%20res.pdf |archive-date=10 September 2008 |access-date=29 March 2008 |publisher=[[Network of African Science Academies]]}}</ref>

=== Nobel Peace Prize in 2007 ===
{{main|2007 Nobel Peace Prize}}
{{wikisource|Al Gore's Nobel Peace Prize acceptance speech}}

In December 2007, the IPCC received the [[Nobel Peace Prize]] "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change". It shared the award with former U.S. Vice-president [[Al Gore]] for his work on climate change and the documentary ''[[An Inconvenient Truth]]''.<ref name="nobelpeaceprize">{{cite web |title=2007 Nobel Peace Prize Laureates |url=http://nobelprize.org/nobel_prizes/peace/laureates/2007/ |access-date=11 October 2007}}</ref>

===Gulbenkian Prize for Humanity in 2022===

In October 2022, the IPCC and [[IPBES]] shared the [[Gulbenkian Prize|Gulbenkian Prize for Humanity]]. The two intergovernmental bodies won the prize because they "produce scientific knowledge, alert society, and inform decision-makers to make better choices for combatting climate change and the loss of biodiversity".<ref name="GulbenkianPrize">{{cite web |title=2022 Gulbenkian Prize for Humanity distinguishes IPBES and IPCC |date=13 October 2022 |url=https://gulbenkian.pt/en/news/2022-gulbenkian-prize-for-humanity-distinguishes-ipbes-and-ipcc/ |access-date=13 October 2022}}</ref>

== See also ==
{{portal|border=no|Environment|Politics|Renewable energy|Global warming|World}}
* {{Annotated link |Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services}}
* {{Annotated link |Intergovernmental Science-Policy Panel on Chemicals, Waste and Pollution}}
* {{Annotated link |United Nations Framework Convention on Climate Change}}
*[[Second Austrian Assessment Report on Climate Change]]
{{Clear}}

== References ==
{{Reflist}}

==External links==
* {{Official website}}
* {{official website|https://www.ipcc-data.org/}} of IPCC Data Distribution Centre (Climate data and guidance on its use)

{{Climate change}}
{{United Nations}}
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[[Category:Intergovernmental Panel on Climate Change| ]]
[[Category:International climate change organizations]]
[[Category:Organizations awarded Nobel Peace Prizes]]
[[Category:United Nations Environment Programme]]
[[Category:Working groups]]
[[Category:World Meteorological Organization]]
[[Category:Environmental organizations established in 1988]]
[[Category:Scientific organizations established in 1988]]
[[Category:Organisations based in Geneva]]
[[Category:Swiss Nobel laureates]]