Lake and Peat Sediments,

 

60

   

 Speleothems,

 

62

   

 Summary,

 

64

6

 

ICE ISOTOPES

 

65

   

 Physical Basis for Deriving Climate Signals from Ice Isotopic Ratio Records,

 

66

   

 Calibration and Resolution,

 

67

   

 Results from Ice Isotopic Ratio Records,

 

67

7

 

GLACIER LENGTH AND MASS BALANCE RECORDS

 

71

   

 Reconstructing Temperature Records from Glacier Records,

 

72

   

 More Detailed Background on Glacier-Length-Based Reconstructions,

 

72

   

 Other Information Available from Glaciers,

 

75

8

 

BOREHOLES

 

77

   

 Boreholes in Rock and Permafrost,

 

78

   

 Limits on Borehole-Based Reconstructions,

 

80

   

 Boreholes in Glacial Ice,

 

81

9

 

STATISTICAL BACKGROUND

 

83

   

 Linear Regression and Proxy Reconstruction,

 

84

   

 Principal Component Regression,

 

89

   

 Validation and the Prediction Skill of the Proxy Reconstruction,

 

92

   

 Quantifying the Full Uncertainty of a Reconstruction,

 

95

10

 

CLIMATE FORCINGS AND CLIMATE MODELS

 

98

   

 Climate Forcings,

 

99

   

 Climate Model Simulations,

 

105

   

 Anthropogenic Forcing and Recent Climate Change,

 

107

11

 

LARGE-SCALE MULTIPROXY RECONSTRUCTION TECHNIQUES

 

110

   

 Evolution of Multiproxy Reconstruction Techniques,

 

111

   

 Strengths and Limitations of Large-Scale Surface Temperature Reconstructions,

 

115

   

 Overall Findings and Conclusions,

 

117

   

 What Comments Can Be Made on the Value of Exchanging Information and Data?,

 

118

   

 What Might Be Done to Improve Our Understanding of Climate Variations Over the Last 2,000 Years?,

 

119

 

 

REFERENCES

 

120

 

 

APPENDIXES

 

 

   

 A  Statement of Task

 

139

   

 B  R Code for Figure 9-2

 

140

   

 C  Biographical Sketches of Committee Members

 

142



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