Working Group I The Physical Science Basis

Working Group I assesses the physical science of climate change.

The IPCC Working Group I (WGI) examines the physical science underpinning past, present, and future climate change.

Scientists all over the world regularly assess the rich body of scientific literature, contributing to an ever-strengthening understanding of how the climate system works, and how it is changing in response to human activity.

The scientific topics assessed by WGI include: greenhouse gases and aerosols in the atmosphere; temperature changes in the air, land and ocean; the hydrological cycle and changing precipitation (rain and snow) patterns; extreme weather; glaciers and ice sheets; oceans and sea level; biogeochemistry and the carbon cycle; and climate sensitivity. The WGI assessment combines observations, palaeoclimate, process studies, theory and modelling into a complete picture of the climate system and how it is changing, including the attribution (or causes) of change.

The WGI assessment provides scientific information relevant for the global community to meet the challenge of climate change. As well as the global scale, WGI looks at variability and changes happening at a regional level, which is closely tied to how impacts and risks to human and natural systems are changing over time. This is, in turn, relates to the assessment of WGII and the need to design effective climate change adaptation policies. Other important policy dimensions of WGI are the assessment of the amount of carbon emissions compatible with climate and energy targets; interactions between land and the climate; and links between climate and air quality. All of these aspects are closely connected with the assessment of WGIII and strategies to mitigate against the impacts of climate change.


These are published materials composed of the full scientific and technical assessment of climate change, generally in three volumes, one for each of the Working Groups of the IPCC, plus a Synthesis Report. Each of the Working Group volumes is composed of individual chapters, an optional Technical Summary and a Summary for Policymakers.

Special Report

Climate Change and Land

August 2019
Special Report

Global Warming of 1.5°C

October 2018
Synthesis Report

AR5 Synthesis Report: Climate Change 2014

October 2014
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Resources related to the preparation of the Working Group I Report

File size
AR6 WGI FOD Guidance Note
April 29, 2019
117 KB
IPCC WGI Visual Style Guide (Updated Version June 2022)
June 1, 2022
3.8 MB
Climate Outreach IPCC Communications Handbook
November 13, 2019
2.9 MB
Role of Authors
November 13, 2019
914 KB
Role of Review Editors
November 13, 2019
90 KB
Code of Conduct
November 13, 2019
394 KB
Guidance note on Confidentiality during the preparation of IPCC reports
November 13, 2019
76 KB
Guidance note on communication and interacting with the media as an IPCC author
November 13, 2019
386 KB
Guidance note for Lead Authors of the IPCC Fifth Assessment Report on Consistent Treatment of Uncertainties
November 13, 2019
3.3 MB
Annex A to Guidance note for Lead Authors of the IPCC Fifth Assessment Report on Consistent Treatment of Uncertainties
November 13, 2019
214 KB
Expert Meeting on Regional Assessment - Meeting Report
November 13, 2019
1.4 MB
Expert Meeting on Short-lived Climate Forcers (SLCF) - Meeting Report
November 13, 2019
4.7 MB


One of the main IPCC activities is the preparation of comprehensive Assessment Reports about the state of scientific, technical and socio-economic knowledge on climate change, its causes, potential impacts and response strategies. The IPCC also produces Special Reports, which are an assessment on a specific issue, and Methodology Reports, which provide practical guidelines for the preparation of greenhouse gas inventories.


Fifty-eighth Session of the IPCC

March 13, 2023


November 6, 2022
Other Event

Interactive Atlas Regional Webinars

October 6, 2022
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Press Release

IPCC wraps up elections in Nairobi

NAIROBI, July 29 – The Intergovernmental Panel on Climate Change (IPCC) completed its elections in Nairobi this morning. During the …

July 2023
Press Release

IPCC elects Jim Skea as the new Chair

NAIROBI, July 26 – Jim Skea of the United Kingdom is the newly elected Chair of the Intergovernmental Panel on …

July 2023
Media Advisory

IPCC gathers in Nairobi to elect the new Bureau

NAIROBI, July 24 – The Intergovernmental Panel on Climate Change (IPCC) is set to begin its 59th Session to elect …

July 2023

Opening Address by IPCC Chair at the Ministerial Segment of the HLPF on SD, ECOSOC, General Assembly

Accelerate Climate Action Now Excellency Madam President Lachezara Stoeva, Excellency Secretary General Antonio Guterres, Excellency President of the General Assembly …

July 2023
Media Advisory

IPCC to elect its new Bureau at the next session in Nairobi

GENEVA, July 17 – The Intergovernmental Panel on Climate Change (IPCC) will be electing its new Bureau and the Bureau …

July 2023
Media Advisory

IPCC at the Bonn Climate Conference

GENEVA, June 2 – The Intergovernmental Panel on Climate Change (IPCC) will be taking an active part in the upcoming …

June 2023
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Robert Vautard

Co-Chair, Working Group I

Xiaoye Zhang

Co-Chair, Working Group I

Vice Chairs


Edvin Aldrian

Vice-Chair, Working Group I

Nana Ama Browne Klutse

Vice-Chair, Working Group I

Ines Camilloni

Vice-Chair, Working Group I

Aida Diongue

Vice-Chair, Working Group I

Sherilee Harper

Vice-Chair, Working Group I

Maheshwar Rupakheti

Vice-Chair, Working Group I

Sonia Seneviratne

Vice-Chair, Working Group I

TSU Staff


Clotilde Péan

Head of TSU


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