In 2025, the planet had its third-hottest year on record, NOAA, NASA, the European Copernicus Climate Change Service, Berkeley Earth, the Japan Meteorological Agency, and the UKMET Office reported. The year 2024 remains the hottest year on record, with 2023 in second place, but only slightly ahead of 2025. (In fact, Carbon Brief concluded that 2023 and 2025 were essentially tied for second place.)
While 2025’s warmth did not set a new record, it was extraordinary because human-caused global warming pushed global temperatures to near-record levels despite the cooling influence of the La Niña phenomenon, which typically suppresses global temperatures. The record-warm years of 2023 and 2024 both lacked this cooling influence, and both were affected by the strong 2023-24 El Niño event. El Niño typically warms the global atmosphere.
According to Berkeley Earth, 9.1% of the Earth’s surface had a record-warm year, including 10.6% of land areas and 8.3% of ocean areas. They estimated that 770 million people — 8.5% of Earth’s population — experienced a locally record warm annual average in 2025. The largest population centers affected by record warmth in 2025 were mostly in Asia, including about 450 million people in China.
Europe and Oceana had their second-warmest year on record; Asia, its third-warmest; North America, its fourth-warmest; South America, its sixth-warmest; and Africa, its seventh-warmest. The Arctic had its second-warmest year on record, and the Antarctic, its fourth-warmest. As reported by Bob Henson yesterday, the contiguous U.S. experienced its fourth-warmest year on record in 2025.
Global satellite-measured temperatures in 2025 for the lowest eight kilometers of the atmosphere were second-warmest in the 47-year satellite record, behind only 2024, according to the University of Alabama, Huntsville.
NOAA is giving a less than 1% chance that 2026 will surpass 2024 as the hottest year on record, with a 75% chance of being a top-five hottest year. If an El Niño event were to arrive in 2026-27, it would boost the odds of 2027 setting a new global record.
A mix of unusually wet and unusually dry conditions for the globe
Asia had its third-wettest year on record during 2025, while Australia and Africa had their 12th- and 15th-wettest, respectively. In contrast, conditions were dry across much of Europe and the Americas, with 2025 ranking as the fifth-driest year on record for Europe and South America, while North America ranked sixth-driest on record.
No clear signs of a peak in global CO2 emissions yet
Carbon dioxide emissions from fossil fuels and cement production rose by around 1.1% in 2025, reaching a record 38.1 billion tons of carbon dioxide, according to the 2025 Global Carbon Budget report by the Global Carbon Project, released November 13. The 1.1% annual increase is roughly on par with the 0.9% average annual increase during the 2010s and higher than the 0.8% growth in 2024. Some highlights from the report:
- The concentration of CO2 in the atmosphere in 2025 was near 426 ppm — about 53% above pre-industrial levels.
- About 8% of the rise in atmospheric CO2 concentration since 1960 is due to climate change weakening the amount of CO2 that the land and ocean surfaces can remove (their sinks).
- The projected rise in fossil CO2 emissions in 2025 was driven by all fuel types: coal +0.8%, oil +1%, natural gas +1.3%.
- The projected emissions for 2025 increased by 6.8% for international aviation (exceeding pre-COVID levels) but remained flat for international shipping.
- Atmospheric CO2 concentrations increased by about 2.3 ppm in 2025, down from the record-high increase of 3.7 ppm observed in 2024. The increase that year was so high mainly because the 2023/2024 El Niño weakened the amount absorbed by land. The decadal average increase of CO2 has been 2.6 ppm per year, suggesting the land absorption largely returned to its pre-El Niño level during 2025.
“With CO2 emissions still increasing, keeping global warming below 1.5°C is no longer plausible,” said Professor Pierre Friedlingstein, of Exeter’s Global Systems Institute, who led the study. “The remaining carbon budget for 1.5°C, 170 billion tons of carbon dioxide, will be gone before 2030 at current emission rate. We estimate that climate change is now reducing the combined land and ocean sinks – a clear signal from Planet Earth that we need to dramatically reduce emissions.”
The other two primary human-emitted heat-trapping gases — methane and nitrous oxide — also reached all-time highs in 2025.
Hottest year on record for total ocean heat content
For the ninth consecutive year, the total heat content in the topmost 2,000 meters of the world’s oceans in 2025 was the hottest in data going back to 1955, according to a study published Friday involving more than 50 scientists from 31 international institutions — Ocean Heat Content Sets Another Record in 2025. The extra ocean heat in 2025 compared to 2024 amounted to 23 zettajoules — more than 200 times the electrical energy usage of the entire planet, the researchers said. About 33% of the global ocean area ranked among its historical (1958–2025) top three warmest conditions, while about 57% fell within the top five.
More than 90% of the increasing heat from human-caused global warming accumulates in the ocean as a result of its large heat capacity. The remaining heating manifests through atmospheric warming, the overall drying and warming of global landmasses, and the melting of land and sea ice. Increases in ocean heat content cause sea level rise through thermal expansion of the water and melting of glaciers in contact with the ocean, resulting in increased coastal erosion and more damaging storm surges. Increased ocean heat content also produces stronger and more rapidly intensifying hurricanes, causes more intense precipitation events that can lead to destructive flooding, contributes to marine heat waves that damage or destroy coral reefs, and disrupts atmospheric circulation patterns. A number of extreme weather events in 2025 can all be linked back to long-term ocean heat accumulation, according to the paper:
Global number of named tropical cyclones: 3rd-highest since 1980
A total of 102 named tropical cyclones occurred across the globe in 2025, which is the third-highest number since 1980, according to the Colorado State Real-Time Tropical Cyclone Activity page. Of those, 52 reached the equivalent of hurricane strength (winds of 74 mph or higher) during 2025 — the ninth-highest number since 1980; 24 reached the equivalent of major hurricane strength (winds of 111 mph or higher), which was near average. The global accumulated cyclone energy, or ACE — an integrated metric of the strength, frequency, and duration of tropical storms — was also near average. There were five Cat 5s globally, which is near the 1990-2025 average of 5.3 per year. NOAA reported that there were 101 named tropical cyclones in 2025, compared to the 1991-2020 average of 87.7.
A La Niña event continues but is expected to end by March
A weak La Niña event continues in the Eastern Pacific, NOAA reported in its January monthly discussion of the state of the El Niño/Southern Oscillation, or ENSO. La Niña conditions are expected to end in the January-March 2026 period (75% chance), becoming ENSO-neutral. An increasing chance of El Niño conditions is predicted as 2026 progresses, according to the NOAA/Columbia University International Research Institute for Climate and Society forecast. The forecast for the August-September-October peak of hurricane season, issued in mid-December, called for a 38% chance of El Niño, a 44% chance of ENSO-neutral, and an 18% chance of La Niña. El Niño conditions tend to suppress Atlantic hurricane activity through an increase in wind shear, but La Niña conditions tend to have the opposite effect.
Arctic sea ice: lowest December extent on record
Arctic sea ice extent during December 2025 was the lowest in the 47-year satellite record, according to the National Snow and Ice Data Center. December 2025 sea ice extent in the Antarctic was the seventh-lowest on record.
For the year, the average sea ice extent and sea ice volume in the Arctic hit a record low, according to Zack Labe (see Bluesky post below). However, the annual minimum (reached on September 10) was not impressively low by recent standards, ranking as the joint-10th lowest in the satellite record.
The annual Arctic Report Card was issued in December and reported these highlights from October 2024 to September 2025:
- Surface air temperatures across the Arctic from October 2024 through September 2025 were the warmest recorded since records began in 1900, including the warmest autumn, second-warmest winter, and third-warmest summer.
- The last 10 years are the 10 warmest on record in the Arctic.
- Since 2006, Arctic annual temperature has increased at more than double the global rate of temperature change.
- Precipitation from October 2024 to September 2025 set a new record high.
- In March 2025, Arctic winter sea ice reached the lowest annual maximum extent in the 47-year satellite record.
- The oldest, thickest Arctic sea ice (> 4 years) has declined by more than 95% since the 1980s. Multiyear sea ice is now largely confined to the area north of Greenland and the Canadian archipelago.
- The Greenland ice sheet lost an estimated 129 billion tons of ice in 2025, less than the annual average of 219 billion tons between 2003 and 2024, but continuing the long-term trend of net loss.
- In 2025, maximum Arctic tundra greenness was the third-highest in the 26-year satellite record, continuing a sequence of record or near-record high values since 2020.
Greenland Ice Sheet loses mass for the 29th consecutive year
The Greenland Ice Sheet lost 105 billion tons of ice in 2024-25, marking the 29th consecutive year it has lost ice, according to a December 2025 post on Carbon Brief by Greenland ice experts Martin Stendel and Ruth Mottram of the Danish Meteorological Institute. However, the amount of ice lost has not been increasing in recent years (Fig. 2).
The 2025 ice melt season saw an unusually early start — May 14, about 12 days earlier than the 1981-2025 average. There is evidence that the length of the melt season in Greenland is lengthening. A remarkably large percentage of the ice sheet was melting at once — from mid-June to the end of September, the area undergoing melting was larger than the 1981-2010 average. In mid-July, melting occurred over a record area. For three days in a row, melting was present over 80% of the ice sheet, peaking at 81.2%, the highest observed since records began in 1981.
Notable global heat and cold marks for December 2025
Weather records expert Maximiliano Herrera documents world temperature extremes in remarkable detail and has provided us with the following info for May. Follow him on Bluesky: @extremetemps.bsky.social
- Hottest temperature in the Northern Hemisphere: 40.6°C (105.1°F) at Garoua, Cameroon, Dec. 29
- Coldest temperature in the Northern Hemisphere: -59.0°C (-74.2°F) at Delyankir, Russia, Dec. 25
- Hottest temperature in the Southern Hemisphere: 47.5°C (117.5°F) at Eyre, Australia, Dec. 17
- Coldest temperature in the Southern Hemisphere: -44.3°C (-47.7°F) at Concordia, Antarctica, Dec. 3
Major weather stations in December 2025: three all-time heat records, one all-time cold record
Among global stations with a record of at least 40 years, three set, not just tied, an all-time heat record in December, one set an all-time cold record:
Kanton Island (Kiribati) max. 35.9°C, December: New national record high for Kiribati
Braeburn (Canada) min. -55.7°C, December 23
Mirnjyi (Antarctica) max. 10.8°C, December 24
Kaimana (Indonesia) max. 37.7°C, December 29
National and territorial heat records of 2025
International weather records researcher Maximiliano Herrera (who posts on Bluesky and X) monitors the pulse of the planet in remarkable detail, and he logged 10 nations or territories that set or tied their all-time reliably measured heat records in 2025 and no nations that set or tied an all-time cold record. Three nations or territories beat or tied their old all-time heat record multiple times in 2025. In 2024, 25 such records were set, the most Herrera has logged in any singe year.
Among global weather stations having at least 40 years of record-keeping, Herrera documented 388 that exceeded (not just tied) their all-time heat record in 2025 and eight that set an all-time cold record. For comparison, 502 stations set their all-time heat record in 2024.
Ten all-time national/territorial heat records set in 2025
- Maldives: 35.8°C (96.4°F) at Hanimadhoo, Feb. 27 (previous record: 35.1°C (95.2°F) at Hanimadhoo, Mar. 24, 2024)
- Togo: 44.0°C (111.2°F) at Mango, Mar. 16 and Apr. 5 (tie)
- Turkey: 50.5°C (122.9°F) at Silopi, Jul. 25
- Kosovo: 42.5°C (108.5°F) at Kline, Jul. 25
- Brunei: 39.2°C (102.6°F) at Sukang, Jul. 29; tied again on Aug. 1 at the same location
- Japan: 41.2°C (106.2°F) at Kaibara, Jul. 30; broken again on Aug. 5 with 41.8°C (107.2°F) at Isesaki
- United Arab Emirates: 51.8°C (125.2°F) at Swiehan, Aug. 1 (tie)
- Martinique (territory of France): 37.0°C (98.6°F) at Le Lamentin, Aug. 22
- St. Eustatius (territory of the Netherlands): 34.4°C (93.9°F) at Roosevelt Airport, Sep. 13
- Kiribati: 35.9°C (96.6°F) at Kanton Island. Dec. 8
No nations or territories set or tied an all-time national/territorial cold record in 2025.
An additional 76 monthly national/territorial heat records beaten or tied in 2025
In addition to the 10 all-time national/territorial records listed above (plus three nations that beat or tied their record in two separate months), 76 nations or territories set monthly all-time heat records in 2025, for a total of 89 monthly all-time records. Here are the additional 76 monthly heat records set in 2025:
- January (6): Cocos Islands, French Southern Territories, Faroe Islands, Maldives, Northern Marianas, Martinique
- February (3): Northern Marianas, Argentina, Togo
- March (8): French Southern Territories, Algeria, Saba, South Korea, Kyrgyzstan, Georgia, Mauritius, Cocos Islands
- April (11): French Southern Territories, British Indian Ocean Territory, Latvia, Estonia, Kuwait, Saudi Arabia, Iraq, Iran, Turkmenistan, Kyrgyzstan, Ireland
- May (5): French Southern Territories, Iceland, Kyrgyzstan, China, Qatar
- June (7): Cocos Islands, Hong Kong, Slovenia, Spain, Portugal, Jersey, Gabon
- July (7): Maldives, Ukraine, Honduras, French Southern Territories, U.S. Virgin Islands, Malaysia, Japan
- August (10): Honduras, Cocos Islands, Lebanon, Albania, French Southern Territories, Israel, Iceland, Grenada, St. Vincent and the Grenadines, Martinique
- September (4): Canada, Namibia, Chile, Central African Republic
- October (5): Taiwan, French Southern Territories, New Caledonia, Cocos Islands, Martinique
- November (4): Singapore, Israel, Cape Verde, U.S. Virgin Islands
- December (6): Kuwait, Dominica, Iceland, Cameroon, Congo, French Guiana
Two nations or territories set an all-time monthly cold record in 2025: Qatar in January, and Puerto Rico in December.
Notable global heat and cold records for 2025
- Hottest temperature in the Northern Hemisphere: 52.8°C (127.0°F) at Shabankareh, Iran, Jul. 19
- Coldest temperature in the Northern Hemisphere: -61.0°C (-77.8°F) at Summit, Greenland, Jan. 16
- Hottest temperature in the Southern Hemisphere: 49.3°C (120.7°F) at Geraldton Airport, Australia, Jan. 20
- Coldest temperature in the Southern Hemisphere: -82.0°C (-115.6°F) at Dome Fuji, Antarctica, Jul. 24
Highest average temperature in the Northern Hemisphere in 2025: 32.1°C (89.8°F) at Makkah (Saudi Arabia)
Highest average temperature in the Southern Hemisphere in 2025: 29.7°C (85.5°F) at Teresina (Brazil)
Three notable hemispherical and continental temperature records set in 2025
- Highest temperature ever recorded in South America in February: 46.5°C (115.7°F) at Rivadavia, Argentina, February 4
- Highest minimum temperature ever recorded in South America in February: 30.8°C (87.4°F) at Catamarca, Argentina, February 10.
- Highest minimum temperature ever recorded in Africa in November: 31.9°C (89.4°F) at Vioolsdrif, South Africa, November 14.
Bob Henson contributed to this post.
Republish our articles for free, online or in print, under a Creative Commons license.
Source link