IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group I: The Physical Science Basis

Chapter 8: Climate Models and their Evaluation

Executive Summary

8.1 Introduction and Overview

8.1.1 What is Meant by Evaluation?

8.1.2 Methods of Evaluation

8.1.3 How Are Models Constructed?

8.2 Advances in Modelling

FAQ 8.1: How Reliable Are the Models Used to Make Projections of Future Climate Change?

8.2.1 Atmospheric Processes

8.2.2 Ocean Processes

8.2.3 Terrestrial Processes

8.2.4 Cryospheric Processes

8.2.5 Aerosol Modelling and Atmospheric Chemistry

8.2.6 Coupling Advances

8.2.7 Flux Adjustments and Initialisation

8.3 Evaluation of Contemporary Climate as Simulated by Coupled Global Models

8.3.1 Atmosphere

8.3.2 Ocean

8.3.3 Sea Ice

8.3.4 Land Surface

8.3.5 Changes in Model Performance

8.4 Evaluation of Large-Scale Climate Variability as Simulated by Coupled Global Models

8.4.1 Northern and Southern Annular Modes

8.4.2 Pacific Decadal Variability

8.4.3 Pacific-North American Pattern

8.4.4 Cold Ocean-Warm Land Pattern

8.4.5 Atmospheric Regimes and Blocking

8.4.6 Atlantic Multi-decadal Variability

8.4.7 El Niño-Southern Oscillation

8.4.8 Madden-Julian Oscillation

8.4.9 Quasi-Biennial Oscillation

8.4.10 Monsoon Variability

8.4.11 Shorter-Term Predictions Using Climate Models

8.5 Model Simulations of Extremes

8.5.1 Extreme Temperature

8.5.2 Extreme Precipitation

8.5.3 Tropical Cyclones

8.5.4 Summary

8.6 Climate Sensitivity and Feedbacks

8.6.1 Introduction

8.6.2 Interpreting the Range of Climate Sensitivity Estimates Among General Circulation Models

8.6.3 Key Physical Processes Involved in Climate Sensitivity

8.6.4 How to Assess Our Relative Confidence in Feedbacks Simulated by Different Models?

8.7 Mechanisms Producing Thresholds and Abrupt Climate Change

8.7.1 Introduction

8.7.2 Forced Abrupt Climate Change

8.7.3 Unforced Abrupt Climate Change

8.8 Representing the Global System with Simpler Models

8.8.1 Why Lower Complexity?

8.8.2 Simple Climate Models

8.8.3 Earth System Models of Intermediate Complexity


Coordinating Lead Authors:

David A. Randall (USA), Richard A. Wood (UK)

Lead Authors:

Sandrine Bony (France), Robert Colman (Australia), Thierry Fichefet (Belgium), John Fyfe (Canada), Vladimir Kattsov (Russian Federation), Andrew Pitman (Australia), Jagadish Shukla (USA), Jayaraman Srinivasan (India), Ronald J. Stouffer (USA), Akimasa Sumi (Japan), Karl E. Taylor (USA)

Contributing Authors:

K. AchutaRao (USA), R. Allan (UK), A. Berger (Belgium), H. Blatter (Switzerland), C. Bonfils (USA, France), A. Boone (France, USA), C. Bretherton (USA), A. Broccoli (USA), V. Brovkin (Germany, Russian Federation), W. Cai (Australia), M. Claussen (Germany), P. Dirmeyer (USA), C. Doutriaux (USA, France), H. Drange (Norway), J.-L. Dufresne (France), S. Emori (Japan), P. Forster (UK), A. Frei (USA), A. Ganopolski (Germany), P. Gent (USA), P. Gleckler (USA), H. Goosse (Belgium), R. Graham (UK), J.M. Gregory (UK), R. Gudgel (USA), A. Hall (USA), S. Hallegatte (USA, France), H. Hasumi (Japan), A. Henderson-Sellers (Switzerland), H. Hendon (Australia), K. Hodges (UK), M. Holland (USA), A.A.M. Holtslag (Netherlands), E. Hunke (USA), P. Huybrechts (Belgium), W. Ingram (UK), F. Joos (Switzerland), B. Kirtman (USA), S. Klein (USA), R. Koster (USA), P. Kushner (Canada), J. Lanzante (USA), M. Latif (Germany), N.-C. Lau (USA), M. Meinshausen (Germany), A. Monahan (Canada), J.M. Murphy (UK), T. Osborn (UK), T. Pavlova (Russian Federationi), V. Petoukhov (Germany), T. Phillips (USA), S. Power (Australia), S. Rahmstorf (Germany), S.C.B. Raper (UK), H. Renssen (Netherlands), D. Rind (USA), M. Roberts (UK), A. Rosati (USA), C. Schär (Switzerland), A. Schmittner (USA, Germany), J. Scinocca (Canada), D. Seidov (USA), A.G. Slater (USA, Australia), J. Slingo (UK), D. Smith (UK), B. Soden (USA), W. Stern (USA), D.A. Stone (UK), K.Sudo (Japan), T. Takemura (Japan), G. Tselioudis (USA, Greece), M. Webb (UK), M. Wild (Switzerland)

Review Editors:

Elisa Manzini (Italy), Taroh Matsuno (Japan), Bryant McAvaney (Australia)

This chapter should be cited as:

Randall, D.A., R.A. Wood, S. Bony, R. Colman, T. Fichefet, J. Fyfe, V. Kattsov, A. Pitman, J. Shukla, J. Srinivasan, R.J. Stouffer, A. Sumi and K.E. Taylor, 2007: Cilmate Models and Their Evaluation. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.