Table of Contents

Report: The Science of Climate Change: Global and U.S. Perspectives

Foreword     ii

Executive Summary     1

1. Introduction     3

2. Observed Changes     5
   1. Changes in Atmospheric Composition     5
   2. Radiative Forcing     6
   3. Changes in Global-Mean Temperature      9
   4. Changes in the Free Atmosphere     10
   5. Precipitation Changes     12

3. Detection and Attribution     14

4. Predicting Future Climate     16
   1. Future Emissions     16
   2. Future Concentrations and Radiative Forcing     17
   3. Future Global-Mean Climate Projections     19

5. Regional Climate Change for the United States     22
   1. Model Evaluation     23
   2. Future Climate     29

6. Changes in Other Aspects of Climate     30
   1. Extremes of Temperatures     30
   2. Changes in Variability     31
   3. Changes in Precipitation Extremes     31
   4. Midlatitude Storms     32
   5. Hurricanes and Tropical Storms     32

7. Conclusion     31

Endnotes       36

References       37

Appendix         44

A1. The Climate System     44

A2. External Forcing and the Earth's Energy Balance     44

A3. Responses to External Forcing     46

A4. Internal Variability of the Climate System     47

A5. Summary of Causes of Climate Change     48