© 2016

Demystifying Climate Models

A Users Guide to Earth System Models


  • A guide to climate simulation and prediction for the non-specialist

  • Includes an introduction to climate science and to the essentials of the problem of predicting climate

  • Intended as an entry point for understanding how models work and for helping judging uncertainties in their output

Open Access

Part of the Earth Systems Data and Models book series (ESDM, volume 2)

Table of contents

  1. Front Matter
    Pages i-xvii
  2. Basic Principles and the Problem of Climate Forecasts

    1. Front Matter
      Pages 1-1
    2. Andrew Gettelman, Richard B. Rood
      Pages 3-12 Open Access
    3. Andrew Gettelman, Richard B. Rood
      Pages 13-22 Open Access
    4. Andrew Gettelman, Richard B. Rood
      Pages 23-35 Open Access
    5. Andrew Gettelman, Richard B. Rood
      Pages 37-58 Open Access
  3. Model Mechanics

    1. Front Matter
      Pages 59-59
    2. Andrew Gettelman, Richard B. Rood
      Pages 61-85 Open Access
    3. Andrew Gettelman, Richard B. Rood
      Pages 87-108 Open Access
    4. Andrew Gettelman, Richard B. Rood
      Pages 109-137 Open Access
    5. Andrew Gettelman, Richard B. Rood
      Pages 139-158 Open Access
  4. Using Models

    1. Front Matter
      Pages 159-159
    2. Andrew Gettelman, Richard B. Rood
      Pages 161-176 Open Access
    3. Andrew Gettelman, Richard B. Rood
      Pages 177-197 Open Access
    4. Andrew Gettelman, Richard B. Rood
      Pages 199-220 Open Access
    5. Andrew Gettelman, Richard B. Rood
      Pages 221-236 Open Access
    6. Andrew Gettelman, Richard B. Rood
      Pages 237-253 Open Access
  5. Back Matter
    Pages 255-274

About this book


This book demystifies the models we use to simulate present and future climates, allowing readers to better understand how to use climate model results. In order to predict the future trajectory of the Earth’s climate, climate-system simulation models are necessary. When and how do we trust climate model predictions? The book offers a framework for answering this question. It provides readers with a basic primer on climate and climate change, and offers non-technical explanations for how climate models are constructed, why they are uncertain, and what level of confidence we should place in them. It presents current results and the key uncertainties concerning them. Uncertainty is not a weakness but understanding uncertainty is a strength and a key part of using any model, including climate models. Case studies of how climate model output has been used and how it might be used in the future are provided. The ultimate goal of this book is to promote a better understanding of the structure and uncertainties of climate models among users, including scientists, engineers and policymakers.


Uncertainties In Climate Models Scenario Uncertainty Model Perfomance Confidence Of Climate Predictions Coupled Climate System Model General Circulation Models Weather Models Model Evaluation And Validation Greenhouse Gases Energy Flows Climate Forcing Keeling Curve Finite Element Model Anthropogenic Climate Change Tropical Cyclones Ozone Assessment Sea-Ice Models Human System Models Type Of Climate Models Prediction Of Extreme Events

Authors and affiliations

  1. 1.Nat'l Cntr For Atmospheric ResearchBoulderUSA
  2. 2.Climate and Space Sciences and EngineeriUniversity of MichiganAnn ArborUSA

About the authors

Andrew Gettelman is a Scientist in the Climate and Global Dynamics and Atmospheric Chemistry and Modeling Laboratories at the National Center for Atmospheric Research (NCAR). He is actively involved in developing atmosphere and chemistry components for global climate models at NCAR. Dr. Gettelman specializes in understanding and simulating cloud processes and their impact on climate, especially ice clouds. He has numerous publications on cloud physics representations in global models, as well as research on climate forcing and feedbacks. He has participated in several international assessments of climate models, particularly for assessing atmospheric chemistry. Gettelman holds a doctorate in Atmospheric Science from the University of Washington, Seattle. He is a recent recipient of the American Geophysical Union Ascent Award, and is a Thompson-Reuters Highly Cited Researcher.


Richard B. Rood is a Professor in the Department of Climate and Space Sciences and Engineering (CLaSP) at the University of Michigan. He is also appointed in the School of Natural Resources and Environment. Prior to joining the University of Michigan, he worked in modeling and high performance computing at the National Aeronautics and Space Administration (NASA). His recent research is focused on the usability of climate knowledge and data in management planning and practice. He has started classes in climate-change problem solving, climate change uncertainty in decision making, climate-change informatics (with Paul Edwards). In addition to publications on numerical models, his recent publications include software engineering, informatics, political science, social science, forestry and public health. Rood’s professional degree is in Meteorology from Florida State University. He recently served on the National Academy of Sciences Committee on A National Strategy for Advancing Climate Modeling. He writes expert blogs on climate change science and problem solving for the Weather Underground Richard Rood is a Fellow of American Meteorological Society and a winner of the World Meteorological Organization’s Norbert Gerbier Award.

Bibliographic information