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
Working Group Report

AR5 Climate Change 2013: The Physical Science Basis

September 2013
Working Group Report

TAR Climate Change 2001: The Scientific Basis

January 2001
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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 Visual Style Guide
April 17, 2019
3.9 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.


IPCC at AGU 2021

December 13, 2021

IPCC at COP 26

The IPCC will be taking part in the UN Climate Change Conference (COP26) in Glasgow from 31 October to 12 …

October 31, 2021
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IPCC Working Group I final report materials, now available

GENEVA, May 5 – The IPCC has updated the website featuring the Working Group I contribution to the IPCC Sixth …

May 2022
Press Release

IPCC advances work on the Synthesis Report of the Sixth Assessment Cycle

GENEVA, 25 Apr – The Intergovernmental Panel on Climate Change (IPCC) opened a four-day-long meeting of experts on Monday in …

April 2022

Sixth Assessment Report Website Content Manager (Closed)

The Intergovernmental Panel on Climate Change (IPCC) is seeking a Website Content Manager to manage and implement publication of the …

January 2022
Media Advisory

The IPCC at COP26 in Glasgow

GENEVA, Oct 26 – The Intergovernmental Panel on Climate Change (IPCC) will be taking part in the 26th Conference of …

October 2021

Information Technology Officer in the Technical Support Unit (IPCC WGI)

Working Group I of the Intergovernmental Panel on Climate Change is filling the position of Information Technology Officer in the …

September 2021

IPCC advances work on final product of upcoming assessment report

GENEVA, Aug 16 – The Intergovernmental Panel on Climate Change (IPCC) opened a week-long virtual meeting of experts on Monday …

August 2021
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Valérie Masson-Delmotte

Co-Chair, Working Group I

Panmao Zhai

Co-Chair, Working Group I

Vice Chairs


Noureddine Yassaa


Carolina Vera


Muhammad Tariq

Vice-Chair, Working Group I

Jan Fuglestvedt

Vice-Chair, Working Group I

Gregory Flato

Vice-Chair, Working Group I

Fatima Driouech

Vice-Chair, Working Group I

Edvin Aldrian

Vice-Chair, Working Group I

TSU Staff


Anna Pirani

Head of TSU

Clotilde Péan

Head of Operations

Sarah Connors

Head of Science Team

Yang Chen

Senior Science Officer

Robin Matthews

Senior Science Officer

Melissa Gomis

Senior Science Officer

Rong Yu

Science Officer

Baiquan Zhou

Science Officer

Nada Caud

Outreach Manager

Katherine Leitzell

Communications Manager

Tom Maycock

Science Editor

Mengtian Huang

Science Officer

Elisabeth Lonnoy

Project Assistant

Diego Cammarano

IT Officer


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