Working Group I The Physical Science Basis

Working Group I assesses the physical science of climate change.

The IPCC Working Group I 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 Working Group I 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 Working Group I 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 Working Group I assessment provides scientific information relevant for the global community to meet the challenge of climate change. As well as the global scale, Working Group I 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 Working Group II and the need to design effective climate change adaptation policies. Other important policy dimensions of Working Group I 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 Working Group III 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
Load More


Resources related to the preparation of the Working Group I contribution to the Sixth Assessment 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.


Sixtieth Session of the IPCC

January 16, 2024


November 30, 2023

Fifty-eighth Session of the IPCC

March 13, 2023
Load More


Press Release

IPCC agrees on the set of scientific reports for the seventh assessment cycle

ISTANBUL, Jan 20 – The Intergovernmental Panel on Climate Change (IPCC) will deliver a set of reports assessing the latest …

January 2024

Data Scientist in the Technical Support Unit (IPCC WGI) [Closed]

Working Group I of the Intergovernmental Panel on Climate Change is filling the position of Data Scientist in the Technical …

January 2024

IPCC Chair’s remarks – North-South Prize of the Council of Europe

Lisbon, 14 Dec 2023, 12 pm CHECK AGAINST DELIVERY Your Excellency, President of the Republic, Mr. Speaker, Madame Secretary General …

December 2023

IPCC Co-Laureate of North-South Prize of the Council of Europe

The Intergovernmental Panel on Climate Change (IPCC) has been declared a co-laureate of the 2022 North-South Prize of the Council …

December 2023

Remarks by IPCC Chair during the Opening ceremony COP28

30 November 2023, Dubai, Unites Arab Emirates CHECK AGAINST DELIVERY Excellencies, Distinguished Delegates, Ladies and Gentlemen, I am honoured to …

November 2023
Media Advisory

The IPCC at COP28

GENEVA, Nov 28 – The Intergovernmental Panel on Climate Change (IPCC) is planning a strong presence at the 28th Conference …

November 2023
Load More



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

Aïda Diongue-Niang

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-Working Group I

Elisabeth Lonnoy

Project Assistant

Gerrit Hansen

Senior Advisor, Strategy and Cooperations

Maxime Chambonnet

IT Officer


Contact information for IPCC Working Group I Technical Support Unit: