Energetics of the Climate System

Preface ix

Chapter 1. A Description of the Main Constraints Regulating the Earth Climate 1

1.1. Generalities about the atmosphere and the ocean 1

1.1.1. The atmosphere 4

1.1.2. A brief comparison between some oceans and the atmosphere's main orders of magnitude 9

1.2. A global view of radiative processes 9

1.3. Past climate history 18

1.4. A global evaluation of climate stability 32

1.4.1. Let us consider the first term of equation [1.8] 33

1.4.2. Let us consider the second term of equation [1.8] 37

1.4.3. A global estimate of climate stability considering another source of complexity: the greenhouse effect 43

1.5. Conclusion 47

Chapter 2. The Vertical Dimension of the Energy Processes of the Climate System: Radiative Processes and Radiative--Convective Models 49

2.1. Radiative processes: generalities 50

2.2. Absorption and greenhouse effect 52

2.3. The role of convection 62

2.4. Diffusion of solar radiation 78

Chapter 3. The Horizontal Motion of Atmospheric and Oceanic Transport 93

3.1. Energy budget at the top of the atmosphere 93

3.2. Energy exchanges with the surface 98

3.3. Transport by the atmosphere and the ocean 113

3.4. Vertical and horizontal transports: the links 117

3.4.1. What is stable stratification? 124

3.5. Conclusion 141

Chapter 4. A Transition from Quasi-Equilibrium to Forcing from Anthropogenic Source: A Cartography of Predictable Phenomena, Uncertainties and Feedback Related to the Climate Response to Anthropogenic Disturbance 143

4.1. A transitory evolution 144

4.1.1. Presentation of the Intergovernmental Panel on Climate Change (IPCC) and its missions 147

4.1.2. A focus on IPCC productions 148

4.1.3. Examples of IPCC production impacts 150

4.1.4. Complexity, a main feature of the Earth climate system transitory evolution 151

4.2. Global temperature change and the role of feedbacks 178

4.2.1. About models' uncertainties and radiative forcing associated with CO2 185

4.2.2. The water vapor feedback 188

4.2.3. The albedo feedback 189

4.2.4. The cloud feedback 190

4.2.5. The lapse-rate feedback 192

4.3. Measured and anticipated impacts: what is predictable? 197

4.3.1. Three generations of model assessments directed toward climate change 198

4.3.2. Socio-economic pathways (SSP) in AR6 205

4.3.3. Articulation between SSP scenarios from AR6 and RCP scenarios from AR5 207

4.3.4. As for the most probable trajectory currently followed 210

4.3.5. Main novelties for the seventh IPCC Assessment Report 213

4.3.6. Method for the evaluation of a probability in IPCC reports 214

Chapter 5. From Scientific Diagnostic to Decision-Making 235

5.1. The role of uncertainties on assessing global warming, accounting for natural variability and estimating climate impacts 236

5.1.1. Process studies and uncertainties 260

5.1.2. From natural variability to climate impacts 279

5.1.3. Zoom about uncertainties and the IPCC 281

5.1.4. Process of uncertainty evaluations by the IPCC as detailed in the Fifth Assessment Report (AR5) 283

5.1.5. Process of uncertainty evaluations by the IPCC as detailed in the Sixth Assessment Report (AR6) 287

5.1.6. Method for the evaluation of a probability in IPCC reports 289

5.2. From global to local climate features: a key shift for the interaction between science and decision-making 290

5.3. From scientific diagnosis to political decision-making 300

5.4. A word of conclusion 301

Appendix 303

References 327

List of Authors 339

Index 341