In an unprecedented and comprehensive scientific review, the 35th annual State of the Climate report, issued by the American Meteorological Society, has laid bare the sobering realities of our planet’s rapidly evolving climate system through 2024. This extensive assessment, informed by 589 scientists from 58 countries, synthesizes a vast array of observational data and peer-reviewed analyses to depict a world where greenhouse gas concentrations, temperatures, sea levels, and oceanic heat content have all ascended to record-breaking highs. These findings amplify the urgent narrative of anthropogenic climate alteration and its multifaceted impacts.
The atmospheric composition in 2024 revealed the highest globally recorded concentrations of the primary greenhouse gases—carbon dioxide, methane, and nitrous oxide. Specifically, CO2 levels averaged at a staggering 422.8 parts per million, a 52% increase from pre-industrial levels near 278 ppm. This acceleration in CO2 accumulation, showing an increase of 3.4 ppm in a single year, underscores the intensification of anthropogenic emissions and the insufficiency of current mitigation efforts. The amplification of greenhouse gases directly corresponds to increased radiative forcing, exacerbating global warming trends observed over recent decades.
Global surface temperatures reached new annual maxima for the second consecutive year, climbing between 0.63 to 0.72 degrees Celsius above the 1991–2020 mean baseline. This warming trajectory is partly attributed to a strong El Niño event spanning late 2023 to early 2024, which enhanced ocean-atmosphere heat exchange and altered atmospheric circulation. Notably, multivariate analyses across six independent temperature datasets converge on this finding, reinforcing the consistency of warming patterns and establishing the decade from 2015 to 2024 as the warmest in the instrumental record, dating back to the 19th century.
The intensification of the hydrological cycle is another hallmark feature of the 2024 climate system, deeply influenced by elevated land and ocean temperatures. Enhanced evaporation over the Northern Hemisphere’s terrestrial surfaces precipitated unprecedented atmospheric water vapor concentrations, with over 20% of the globe recording their highest historical values for total column water vapor. Consequentially, global precipitation totals rose sharply, marking 2024 as the third wettest year since comprehensive satellite records began in 1983. The data also revealed record-breaking extreme precipitation events, such as Dubai’s extraordinary 24-hour rainfall of 250 millimeters in April, a testament to the capacity of a warming atmosphere to transport and deposit moisture more intensely.
Oceanic conditions reflected the state of extreme warmth as well. Persistent El Niño conditions maintained sea surface temperatures at record highs through mid-year 2024, surpassing the previous yearly record set in 2023. Marine heatwaves impacted approximately 91% of the global ocean surface in 2023, disrupting marine ecosystems profoundly, while marine cold spells were at a historic low. This thermal anomaly represents an alarming shift in ocean energy balance and has cascading effects on oceanic circulation patterns, marine biodiversity, and carbon sequestration processes.
Furthermore, ocean heat content, which accounts for over 90% of excess heat retained by the Earth system due to greenhouse gas forcing, ascended to unprecedented depths, measuring from the surface to 2000 meters. This deep ocean warming influences thermal expansion and directly contributes to sea level rise, which in 2024, was recorded at an average of 105.8 millimeters above satellite altimetry baselines established in 1993. The relative contributions to sea level rise from ocean thermal expansion and cryospheric ice melt remain significant, with meltwater from glaciers and ice sheets contributing an estimated 2.1 millimeters per year since 2005.
The cryosphere exhibited dramatic transformations. The Arctic’s temperature anomaly placed 2024 as the second warmest year within a 125-year observational record, with autumn months reaching unprecedented warmth. The summer experienced extreme heatwaves reaching record high temperatures in the North American Arctic and Svalbard regions. Variability in snow cover duration caused disparate impacts within the Arctic, where parts of Canada witnessed the shortest 21st-century snow retention, contrasting with prolonged snow cover in northern Europe and Asia. Sea ice extent revealed troubling declines; the maximum sea ice area was the second smallest on record, with minimum extents similarly reduced, highlighting persistent polar warming.
Antarctica continued its trend of diminished sea ice extent, following a record low in 2023 to only marginally larger but still significantly below average coverage in 2024. Both daily minimum and maximum sea ice extents have consistently ranked among the lowest in satellite records since 2016, signaling potential shifts in Southern Ocean dynamics and feedback mechanisms that may accelerate ice mass loss and global climate feedback loops.
Glacial systems worldwide faced the most substantial mass loss recorded in the five-decade observational history, with all 58 reference glaciers monitored across five continents showing continued retreat. South America’s tropical Andes bore extensive losses, with the complete disappearance of glaciers in Venezuela marking a historically unprecedented event in the region. Similarly, Colombia’s Conejeras Glacier has been declared extinct, underscoring the vulnerability of tropical glaciers to rising temperatures and altered precipitation regimes, with dire implications for hydrological resources and downstream ecosystems.
Tropical cyclone activity in 2024 diverged from previous storm seasons by experiencing below-average frequency—82 named storms versus the 1991–2020 average of 87. Nevertheless, the intensity and destructiveness of several storms shattered records and wrought catastrophic human and economic tolls. Notably, Hurricane Helene induced record flooding from Florida to the southern Appalachian Mountains, resulting in over 200 fatalities, the highest U.S. death toll from a hurricane since Katrina in 2005. Hurricane Milton’s rapid succession following Helene highlighted changing storm dynamics, while Super Typhoon Yagi’s impact on China and Vietnam caused over 800 fatalities, revealing the severe humanitarian consequences of powerful tropical systems in vulnerable regions.
The State of the Climate report, published as a special supplement in the Bulletin of the American Meteorological Society, continues its legacy as the most comprehensive, rigorously peer-reviewed annual update on Earth’s climatic condition. By integrating multidisciplinary data streams from atmospheric, terrestrial, cryospheric, and oceanographic observations, it serves as an essential instrument for climate scientists, policy makers, and the public to understand the accelerating pace and breadth of global climate changes. The report’s findings reiterate the critical necessity of sustained global efforts to mitigate greenhouse gas emissions and enhance adaptive resilience to the irrevocable transformations unfolding in the Earth’s climate system.
Subject of Research:
Climate Change and Global Climate System Indicators
Article Title:
Earth’s 2024 Climate: Record Highs in Greenhouse Gases, Temperatures, and Oceanic Heat Mark Accelerated Global Change
News Publication Date:
2025
Web References:
https://www.ametsoc.org/ams/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/
References:
The State of the Climate in 2024, Bulletin of the American Meteorological Society (2025)
Image Credits:
“The State of the Climate in 2024” © American Meteorological Society, 2025
Keywords:
Climatology, Earth systems science, Atmospheric science, Hydrology, Natural disasters, Meteorology, Climate change, Climate data, Climate sensitivity, Climate systems, Climate variability, Global temperature, Antarctic climate, Polar climates, Tropical climates, Mediterranean climate, El Nino, La Nina, Seasonal changes, Atmosphere, Cryosphere, Anthropogenic climate change, Climate change effects
