The "State of the Climate in 2023" report provides a comprehensive overview of global climate indicators, notable weather events, and related data. The year 2023 was characterized by a transition from La Niña to a strong El Niño, which led to record-high global temperatures. Atmospheric concentrations of major greenhouse gases reached unprecedented levels, contributing to these temperature records. The report covers a wide range of climate phenomena, including temperature anomalies, changes in the cryosphere, and the impacts of these changes on ecosystems and human health. The findings highlight the urgent need for climate action, as the warming trends and associated impacts continue to intensify.
Authors
- Pages
- 498
- Published in
- United States of America
Table of Contents
- Abstract 4
- Introduction 15
- Global Climate 26
- Global Oceans 170
- The Tropics 228
- The Arctic 291
- Antarctica and the Southern Ocean 345
- Regional Climates 385
- Authors and affiliations 29
- a. Overview 35
- Sidebar 2.1: Impacts of extreme global temperatures and events in 2023 36
- b. Temperature 43
- 1. Global surface temperature 43
- Sidebar 2.2: Near-surface equivalent temperature as a key climate change metric 44
- 2. Lake surface water temperature 47
- 3. Night marine air temperature 49
- 4. Surface temperature extremes 51
- 5. Tropospheric temperature 53
- 6. Stratospheric temperature 55
- c. Cryosphere 57
- 1. Permafrost temperature and active-layer thickness 57
- 2. Rock glacier velocity 58
- 3. Alpine glaciers 60
- 4. Lake ice 62
- 5. Northern Hemisphere continental snow cover extent 64
- d. Hydrological cycle—atmosphere 66
- 1. Surface humidity 66
- 2. Humid-heat extremes over land 69
- 3. Total column water vapor 71
- 4. Upper-tropospheric humidity 73
- 5. Precipitation 75
- 6. Land surface precipitation extremes 76
- 7. Cloudiness 77
- 8. Lake water storage 80
- 9. Groundwater and terrestrial water storage 81
- 10. Soil moisture 83
- 11. Monitoring global drought using the self-calibrating Palmer Drought Severity Index 84
- 12. Land evaporation 86
- e. Atmospheric circulation 88
- 1. Mean sea level pressure and related modes of variability 88
- 2. Land and ocean surface winds 90
- 3. Upper air winds 93
- 4. Thunder hours 95
- f. Earth radiation budget 97
- 1. Earth radiation budget at top-of-atmosphere 97
- 2. Mauna Loa apparent transmission record 99
- g. Atmospheric composition 101
- 1. Long-lived greenhouse gases 101
- 2. Ozone-depleting substances 104
- 3. Tropospheric aerosols 105
- 4. Tropospheric ozone 108
- 5. Stratospheric aerosols 110
- 6. Stratospheric ozone 113
- 7. Stratospheric water vapor 115
- 8. Carbon monoxide 117
- h. Land surface properties 119
- 1. Terrestrial surface albedo dynamics 119
- 2. Terrestrial vegetation dynamics 120
- 3. Biomass burning 121
- 4. Phenology of primary producers 123
- 5. Vegetation optical depth 127
- Acknowledgments 129
- Appendix 1: Acronyms 134
- Appendix 2: Datasets and sources 138
- Appendix 3: Supplemental materials 149
- References 155
- Authors and affiliations 173
- a. Overview 176
- b. Sea-surface temperature 177
- Sidebar 3.1: Marine heatwaves in 2023 181
- c. Ocean heat content 183
- d. Salinity 187
- 1. Introduction 187
- 2. Sea-surface salinity 187
- 3. Subsurface salinity 189
- e. Global ocean heat, freshwater, and momentum fluxes 192
- 1. Surface heat fluxes 193
- 2. Surface freshwater fluxes 195
- 3. Wind stress 195
- 4. Long-term perspective 196
- f. Sea level variability and change 197
- g. Surface currents 201
- 1. Pacific Ocean 201
- 2. Indian Ocean 203
- 3. Atlantic Ocean 203
- h. Meridional overturning circulation and heat transport in the Atlantic Ocean 205
- i. Global ocean phytoplankton 208
- j. Global ocean carbon cycle 212
- 1. Introduction 212
- 2. Air–sea carbon dioxide fluxes 212
- 3. Ocean interior inventory estimates 214
- Appendix 1: Acronyms 216
- Appendix 2: Datasets and sources 218
- References 222
- Authors and affiliations 231
- a. Overview 233
- b. ENSO and the tropical Pacific 235
- 1. Oceanic conditions 235
- 2. Atmospheric circulation 237
- 3. Global precipitation 238
- c. Tropical intraseasonal activity 239
- d. Intertropical convergence zones 242
- 1. Pacific 242
- 2. Atlantic 244
- e. Global monsoon summary 246
- 1. NH and SH land monsoon precipitation 246
- 2. Regional monsoon precipitation and circulation 247
- f. Indian Ocean dipole 250
- g. Tropical cyclones 252
- 1. Overview 252
- 2. Atlantic basin 253
- 3. Eastern North Pacific and central North Pacific basins 259
- 4. Western North Pacific basin 262
- 5. North Indian Ocean basin 267
- 6. South Indian Ocean basin 269
- 7. Australian basin 271
- 8. Southwest Pacific basin 272
- h. Tropical cyclone heat potential 275
- Sidebar 4.1: Hurricane Otis: The strongest landfalling hurricane on record for the west coast of Mexico 278
- Sidebar 4.2: Tropical Cyclone Freddy: The world's longest-lived tropical cyclone 280
- Appendix 1: Acronyms 281
- Appendix 2: Datasets and sources 283
- Appendix 3: Supplemental materials 286
- References 287
- Authors and affiliations 294
- a. Overview 297
- b. Atmosphere 299
- 1. The arctic troposphere in 2023 300
- 2. The arctic stratosphere in 2023 300
- Sidebar 5.1: The February 2023 major sudden stratospheric warming 302
- c. Surface air temperature 305
- 1. Brief summary of impacts and overview 305
- 2. Annual perspectives 305
- 3. Seasonal patterns 305
- Sidebar 5.2: Summer 2023 weather and climate impacts 307
- d. Precipitation 309
- 1. Introduction 309
- 2. 2023 Summary 309
- 3. Regional anomalies 309
- 4. Historical perspective 310
- 5. Heavy precipitation events 310
- e. Sea-surface temperature 312
- f. Sea ice 315
- 1. Sea-ice extent 315
- 2. Sea-ice age, thickness, and volume 316
- g. Greenland Ice Sheet 318
- h. Glaciers and ice caps outside Greenland 321
- i. Terrestrial snow cover 325
- j. Permafrost 328
- 1. Permafrost temperatures 328
- 2. Active layer thickness 330
- k. Tundra greenness 332
- Appendix 1: Acronyms 335
- Appendix 2: Datasets and sources 336
- References 340
- Authors and affiliations 348
- a. Overview 351
- b. Atmospheric circulation and surface observations 353
- c. Ice-sheet surface mass balance 357
- d. Ice-sheet seasonal melt extent and duration 360
- e. Ice-sheet mass balance 363
- f. Sea-ice extent, concentration, and seasonality 365
- g. Southern Ocean 369
- 1. Sea-surface temperature, salinity, and mixed-layer depth 369
- 2. Air–sea heat flux 369
- 3. Upper ocean heat content 370
- 4. Ocean biogeochemistry 370
- h. 2023 Antarctic ozone hole 372
- Acknowledgments 376
- Appendix 1: Acronyms 377
- Appendix 2: Datasets and sources 378
- References 381
- Authors and affiliations 388
- a. Overview 393
- b. North America 394
- 1. Canada 394
- 2. United States 396
- 3. Mexico 399
- Sidebar 7.1: Record-breaking wildfire season in Canada 401
- c. Central America and the Caribbean 404
- 1. Central America 404
- 2. Caribbean 406
- d. South America 409
- 1. Northern South America 409
- 2. Central South America 411
- 3. Southern South America 415
- Sidebar 7.2: Drought in South America in 2023: Amazonia and Altiplano 417
- e. Africa 419
- 1. North Africa 420
- 2. West Africa 423
- 3. Central Africa 425
- 4. Eastern Africa 427
- 5. Southern Africa 430
- 6. Western Indian Ocean island countries 433
- f. Europe and the Middle East 437
- 1. Overview 437
- 2. Western Europe 441
- 3. Central Europe 442
- 4. Iberian Peninsula 444
- 5. The Nordic and Baltic countries 446
- 6. Central Mediterranean region 447
- 7. Eastern Europe 449
- 8. Middle East 451
- 9. Türkiye and South Caucasus 452
- Sidebar 7.3: European drought conditions in 2023 454
- g. Asia 456
- 1. Overview 456
- 2. Russia 459
- 3. East and Southeast Asia 462
- 4. South Asia 463
- 5. Southwest Asia 466
- 6. Central Asia 468
- Sidebar 7.4: Record-breaking high temperatures over North China in October 2023 470
- h. Oceania 473
- 1. Overview 473
- 2. Northwest Pacific and Micronesia 473
- 3. Southwest Pacific 477
- 4. Australia 480
- 5. Aotearoa New Zealand 483
- Acknowledgments 486
- Appendix 1: Acronyms 487
- Appendix 2: Supplemental materials 489
- References 496
