IPCC Working Group I
IPCC Working Group I assesses the scientific aspects of the climate system and climate change for the Intergovernmental Panel on Climate Change (IPCC). It is responsible for producing reports as part of IPCC's multi-volume Assessments. IPCC Assessments with Working Group I reports were released in 1990, 1995, 2001, and 2007. The next Working Group I report (for Assessment Report 5 or "AR5") is scheduled to be finalized in September 2013. IPCC Working Group I is composed of an international group of scientists. Writing team membership for the Working Group II contribution to the AR5 consists of 259 Coordinating Lead Authors, Lead Authors, and Review Editors.
The reports of IPCC Working Groups have been among the most influential scientific reports on climate change
Contents
Background
The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (WMO) and United Nations Environment Programme (United Nations Environment Programme (UNEP)) (UNEP) to assess scientific, technical and socio-economic information relevant for the understanding of climate change, its potential impacts and options for adaptation and mitigation. It is open to all Members of the United Nations and the WMO.
The IPCC work is shared among three Working Groups, a Task Force and a Task Group. The activities of each Working Group and of the Task Force are coordinated and administrated by a Technical Support Unit: Working Group I, Working Group II (IPCC Working Group I), Working Group III (IPCC Working Group I), and the Task Force on National Greenhouse Gas Inventiories. Each of the groups are focused on a particular area relating to climate change.
The IPCC Working Group I (WGI) assesses the physical scientific aspects of the climate system and climate change. The main topics assessed by WGI include: changes in greenhouse gases and aerosols in the atmosphere; observed changes in air, land and ocean temperatures, rainfall, glaciers and ice sheets, oceans and sea level; historical and paleoclimatic perspective on climate change; biogeochemistry, carbon cycle, gases and aerosols; satellite data and other data; climate models; climate projections, causes and attribution of climate change.
Working Group IBureau
The WGIBureau is responsible for organization of the Working Group. The co-chairs of the WGI work with the co-chairs of the WGII (Impact and Adaptation), WGIII (Mitigation), the Task Force on National Greenhouse Gas Inventories, and the IPCCchairs and vice-chairs to accomplish goals of the IPCC.
The Bureau consists of two co-chairs and six vice-chairs. As of the date of this article, the two co-chairs for the WGIIBureau are Thomas Stocker (Switzerland) and Dahe Qin (China). The six vice-chairs are held by Jean Jouzel (France), Abdalah Mokssit (Morocco), Fatemah Rahimzadeh (Islamic Republic of Iran), Fredolin T. Tangang (Malaysia), David Wratt (New Zealand), and Francis Zwiers (Canada).
Assessment Reports
First Assessment Report (1990)
The Contribution of Working Group I to the First Assessment Report of the Intergovernmental Panel on Climate Change was "Climate Change: The IPCC Scientific Assessment (1990)"- Cover (Front & Back)
- Front Matters (IPCC Working Group I)
- Policymakers Summary
- Introduction (IPCC Working Group I)
- Chapter 1 (IPCC Working Group I) - Greenhouse Gases and Aerosols
- Chapter 2 (IPCC Working Group I) - Radiative Forcing of Climate
- Chapter 3 (IPCC Working Group I) - Processes and Modelling
- Chapter 4 (IPCC Working Group I) - Validation of Climate Models
- Chapter 5 (IPCC Working Group I) - Equilibrium Climate Change - and its Implications for the Future
- Chapter 6 (IPCC Working Group I) - Time-Dependent Greenhouse-Gas-Induced Climate Change
- Chapter 7 (IPCC Working Group I) - Observed Climate Variations and Change
- Chapter 8 (IPCC Working Group I) - Detection of the Greenhouse Effect in the Observations
- Chapter 9 (IPCC Working Group I) - Sea Level Rise
- Chapter 10 (IPCC Working Group I) - Effects on Ecosystems
- Chapter 11 (IPCC Working Group I) - Narrowing the Uncertainties: A Scientific Action Plan for Improved Prediction of Global Climate Change
- Annex (IPCC Working Group I) - Climatic consequences of emissions
- Appendix 1 (IPCC Working Group I) - Emissions Scenarios from the Response Strategies Working Group of the IPCC
- Appendix 2 (IPCC Working Group I) - Organisation of lPCC and WG I
- Appendix 3 (IPCC Working Group I) - Contributors to IPCC WG I Report
- Appendix 4 (IPCC Working Group I) - Reviewers of IPCC WG I Report
- Appendix 5 (IPCC Working Group I) - Acronyms: Institutions
- Appendix 6 (IPCC Working Group I) - Acronyms: Programmes & Miscellaneous
- Appendix 7 (IPCC Working Group I) - Units
- Appendix 8 (IPCC Working Group I) - Chemical Symbols
- Full Report (29,44 MB)
1992 Supplement
In 1992, Working Group I released "Climate Change 1992: The Supplementary Report to the IPCC Scientific Assessment"- Cover (Front & Back)
- Front Matters (IPCC Working Group I) 2
- The 1992 IPCC Supplement - Scientific Assessment
- Section A (IPCC Working Group I) - Greenhouse Gases (title page)
- Section A1 (IPCC Working Group I) - Greenhouse Gases: Sources and Sinks
- Section A2 (IPCC Working Group I) - Radiative Forcing of Climate
- Section A3 (IPCC Working Group I) - Emissions Scenarios for the IPCC: an Update
- Section B (IPCC Working Group I) - Climate Modelling, Climate Prediction and Model Validation
- Section C (IPCC Working Group I) - Observed Climate Variability and Change
- Annex (IPCC Working Group I) - Climatic consequences of emissions and comparison of IS92a and SA90
- Appendix 1 (IPCC Working Group I) 2 - Organization of IPCC and Working Group I
- Appendix 2 (IPCC Working Group I) 2 - Contributors to the IPCC Working Group I Report
- Appendix 3 (IPCC Working Group I) 2 - Reviewers of the IPCC Working Group I Report
- Appendix 4 (IPCC Working Group I) 2 - Acronyms
- Appendix 5 (IPCC Working Group I) 2 - Units
- Appendix 6 (IPCC Working Group I) 2 - Chemical Symbols
Second Assessment Report (1995)
The Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change was "Climate Change 1995: The Science of Climate Change"Full Report (PDF)
Third Assessment Report (2001)
The Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change was "Climate Change 2001: The Scientific Basis"
- Summary
- Foreword
- Preface (IPCC Working Group I)
- Summary for Policymakers (IPCC Working Group I)
- Technical Summary (IPCC Working Group I)
- 1 The Climate System: an Overview
- 2 Observed Climate Variability and Change
- 3 The Carbon Cycle and Atmospheric Carbon Dioxide
- 4 Atmospheric Chemistry and Greenhouse Gases
- 5 Aerosols, their Direct and Indirect Effects
- 6 Radiative Forcing of Climate Change
- 7 Physical Climate Processes and Feedbacks
- 8 Model Evaluation
- 9 Projections of Future Climate Change
- 10 Regional Climate Information - Evaluation and Projections
- 11 Changes in Sea Level
- 12 Detection of Climate Change and Attribution of Causes
- 13 Climate Scenario Development
- 14 Advancing Our Understanding
- Appendix I Glossary (IPCC Working Group I)
- Appendix II SRES Tables (IPCC Working Group I)
- Appendix III Contributors to the IPCC WGI Third Assessment Report (IPCC Working Group I)
- Appendix IV Reviewers of the IPCC WGI Third Assessment Report (IPCC Working Group I)
- Appendix V Acronyms and Abbreviations (IPCC Working Group I)
- Appendix VI Units (IPCC Working Group I)
- Appendix VII Some Chemical Symbols used in this Report (IPCC Working Group I)
- Appendix VIII Figures and Tables in this Report (IPCC Working Group I)
Fourth Assessment Report (2007)
The Contribution of Working Group I to the Fourth Assessment Report was "Climate Change 2007 - The Physical Science Basis" was launched on 2 February 2007 in Paris.
The report, described as "the most comprehensive and up-to-date scientifi c assessment of past, present and future climate change" includes information on changes in greenhouse gases and aerosols in the atmosphere and the extent to which they affect climate. It provides details of recent changes in air, land and ocean temperatures, rainfall, glaciers and ice sheets and considers a large amount of new satellite and other data that have not been assessed previously. A paleoclimatic perspective considers the Earth's past cold and warm periods and the understanding of climate processes that can be gained from these. New information on feedbacks arising from the interaction of climate change with the biosphere and geochemistry is also considered. The most recent climate models were evaluated in detail, as is their use to explain observed climate change in terms of different driving factors. Projections of future climate change using climate models are considered broadly and cover near term climate change, the degree to which this is 'committed' due to past increases in greenhouse gases, and a range of potential longer term climate changes. Patterns of future climate change are considered both globally and regionally.
Working Group I Report: The Physical Science Basis Front Matter (IPCC Working Group I) (IPCC Working Group I) * Summary for Policymakers (IPCC Working Group I) 2 * Technical Summary (IPCC Working Group I) 2 * Frequently Asked Questions (IPCC Working Group I) (extracted from chapters below - for the public relating to common questions regarding climate change.) * Chapter 1 Historical Overview of Climate Change Science (IPCC Working Group I) * Chapter 2 Changes in Atmospheric Constituents and in Radiative Forcing (IPCC Working Group I) * Chapter 3 Observations: Surface and Atmospheric Climate Change (IPCC Working Group I) * Chapter 4 Observations: Changes in Snow, Ice and Frozen Ground (IPCC Working Group I) * Chapter 5 Observations: Oceanic Climate Change and Sea Level (IPCC Working Group I) * Chapter 6 Palaeoclimate (IPCC Working Group I) * Chapter 7 Couplings Between Changes in the Climate System and Biogeochemistry (IPCC Working Group I) * Chapter 8 Climate Models and their Evaluation (IPCC Working Group I) * Chapter 9 Understanding and Attributing Climate Change (IPCC Working Group I) * Chapter 10 Global Climate Projections (IPCC Working Group I) * Chapter 11 Regional Climate Projections (IPCC Working Group I) * Annexes: (1) Glossary, (2) Authors, (3) Reviewers, (4) Acronyms * Index * Uncertainty Guidance Note for the Fourth Assessment Report * Errata for the Working Group I Fourth Assessment Report * Figures
Fifth Assessment Report
The IPCC Fifth Assessment Report (AR5) will provide an update of knowledge on the scientific, technical and socio-economic aspects of climate change, with all information contributed by select authors from each of the working groups and task forces. WGI's contributions are based around their area of expertise, and will be focused around the "physical science basis" for climate change. The outline of the WGI contribution to the AR5 was approved at the 11th Session of Working Group I and accepted by the 31st Session of the IPCC meeting in Bali, Indonesia, 26-29 October 2009.
The report by Working Group I to the multivolume Fifth Assessment Report (AR5) is scheduled for completion in September 2013 and to include the following:
Summary for Policy Makers | |
Technical Summary | |
Chapter 1: | Introduction Executive Summary • Rationale and key concepts of the WG1 contribution • Treatment of uncertainty • Climate change projections since FAR Frequently Asked Questions |
Chapter 2: | Observations: Atmosphere and Surface Executive Summary • Changes in surface temperature and soil temperature • Changes in temperature, humidity and clouds • Changes in atmospheric composition • Changes in radiation fields and energy budget • Changes in hydrology, runoff, precipitation and drought • Changes in atmospheric circulation, including wind • Spatial and temporal patterns of climate variability • Changes in extreme events, including tropical and extratropical storms Frequently Asked Questions |
Chapter 3: | Observations: Ocean Executive Summary • Changes in ocean temperature and heat content • Ocean salinity change and freshwater fluxes • Sea level change, ocean waves and storm surges • Ocean biogeochemical changes, including ocean acidification • Changes in ocean surface processes • Changes in ocean circulation • Spatial and temporal patterns of ocean variability Frequently Asked Questions |
Chapter 4: | Observations: Cryosphere Executive Summary • Changes in ice sheets, including mass balance • Changes in ice shelves • Changes in glaciers and ice caps • Sea ice variability and trends • Snow and ice cover variability and trends • Changes in frozen ground • Dynamics of ice sheets, ice shelves, ice caps, glaciers and sea ice Frequently Asked Questions |
Chapter 5: | Information from Paleoclimate Archives Executive Summary • Characteristics of early instrumental, documentary and natural climate archives • Reconstruction of radiative forcing and climate response • Reconstruction of regional variability and extremes • Abrupt climate changes and their regional expression • Sea level and ice sheets: patterns, amplitudes and rates of change • Paleoclimate perspective on irreversibility in the climate system • Paleodata-model intercomparisons Frequently Asked Questions |
Chapter 6: | Carbon and Other Biogeochemical Cycles Executive Summary • Past changes in CO2, CH4, N2O and biogeochemical cycles • Recent trends in global and regional sources, sinks and inventories, including land use change • Processes and understanding of changes, including ocean acidification • Interactions between the carbon and other biogeochemical cycles, including the nitrogen cycle • Projections of changes in carbon and other biogeochemical cycles • Greenhouse gas stabilisation • Carbon cycle – climate feedbacks and irreversibility • Geoengineering involving the carbon cycle Frequently Asked Questions |
Chapter 7: | Clouds and Aerosols Executive Summary • Observations of clouds and their representation in models • Coupling of clouds, water vapour, precipitation and the large-scale circulation • Cloud and water vapour feedbacks and their effects on climate sensitivity • Observations of aerosols and their representation in models • Aerosol types including black carbon: chemistry, sources, sinks and distribution • Direct and indirect aerosol forcing and effects, including contrails and cosmic rays • Aerosol-cloud-precipitation interactions • Geoengineering involving clouds and aerosols Frequently Asked Questions |
Chapter 8: | Anthropogenic and Natural Radiative Forcing Executive Summary • Natural radiative forcing changes: solar and volcanic • Anthropogenic radiative forcing, including effects from land surface changes • Effects of atmospheric chemistry and composition • Spatial and temporal expression of radiative forcing • Greenhouse gas and other metrics, including Global Warming Potential (GWP) and Global Temperature Change Potential (GTP) Frequently Asked Questions |
Chapter 9: | Evaluation of Climate Models Executive Summary • The hierarchy of climate models: from global to regional • Downscaling methods • Assessing model performance, including quantitative measures and their use • New model components and couplings • Representation of processes and feedbacks in climate models • Simulation of recent and longer term records • Simulation of regional patterns, variability and extremes Frequently Asked Questions |
Chapter 10: | Detection and Attribution of Climate Change: from Global to Regional Executive Summary • Evaluation of methodologies • Atmospheric and surface changes • Changes in ocean properties • Cryosphere changes • Extreme events • Pre-instrumental perspective • Implications of attribution for projections Frequently Asked Questions |
Chapter 11: | Near-term Climate Change: Projections and Predictability Executive Summary • Predictability of interannual to decadal climate variations and change • Projections for the next few decades • Regional climate change, variability and extremes • Atmospheric composition and air quality • Possible effects of geoengineering • Quantification of the range of climate change projections Frequently Asked Questions |
Chapter 12: | Long-term Climate Change: Projections, Commitments and Irreversibility Executive Summary • Scenario description • Projections for the 21st century • Projections beyond the 21st century • Regional climate change, variability and extremes • Forcing, response and climate sensitivity • Climate change commitment and inertia • Potential for abrupt change and irreversibility in the climate system • Quantification of the range of climate change projections Frequently Asked Questions |
Chapter 13: | Sea Level Change Executive Summary • Synthesis of past sea level change and its components • Models for sea level change • Projections of globally averaged sea level rise • Projections of the regional distribution of sea level change • Extreme sea level events • Potential ice sheet instability and its implications • Multi-century projections Frequently Asked Questions |
Chapter 14: | Climate Phenomena and their Relevance for Future Regional Climate Change Executive Summary • Patterns of variability: observations, understanding and projections • Monsoon systems: observations, understanding and projections • Extremes: observations, understanding and projections • Interconnections among phenomena Frequently Asked Questions |
Annex I: Atlas of Global and Regional Climate Projections Annex II: Glossary Annex III: Acronyms and Regional Abbreviations Annex IV: List of Authors Annex V: List of Reviewers Index |
Further Reading:
- Inter-governmental Panel on Climate Change (IPCC)
- IPCCWorking Group I
- AR4:WGI
- AR5:WGI