LONDON — The year 2026 is now likely to finish tied with 2024 as the warmest year ever recorded, according to a major new Carbon Brief analysis published on Tuesday, 3 November 2026, and the same analysis warns that 2027 could go considerably further. Drawing on six global temperature datasets, climate scientist Dr Zeke Hausfather gives 2026 a 67% chance of beating the 2024 record and projects the year to end at around 1.52°C above pre-industrial levels. He puts 2027 at around 1.7°C, with a 96% chance of becoming the warmest year on record, driven by a rapidly strengthening El Niño forecast to peak at around 4°C above average this winter.
Illustration: Earth glows with record heat as 2026 challenges 2024 for warmest year on record.
What Happened
Carbon Brief published its latest quarterly "state of the climate" update on 3 November 2026, updated on Wednesday, 4 November, analysing six global temperature datasets: NASA's GISTEMP, NOAA GlobalTemp, the Met Office Hadley Centre and University of East Anglia's HadCRUT5, Berkeley Earth, the Copernicus/ECMWF ERA5 reanalysis, and the Japan Meteorological Agency's JRA-3Q reanalysis. With three-quarters of the year complete, it finds 2026 is virtually certain to be the warmest or second-warmest year on record.
The year began quietly, with January to June each cooler than the same month in 2024 as weak La Niña gave way to a developing El Niño. That changed in the third quarter: July was the second-warmest July in the six-dataset average, and August set a new monthly record by around 0.12°C, the warmest August on record in every one of the six datasets. September was still the second-warmest September on record, at around 1.62°C, and July to September 2026 effectively tied the same period in 2023 as the warmest on record, at around 1.57°C.
January to September 2026 was the second-warmest such period on record, at around 1.45°C above pre-industrial levels, behind only 2024 by around 0.06°C. Carbon Brief's statistical model, combining observed temperatures through September with the latest El Niño forecasts, now projects 2026 to end at around 1.52°C above pre-industrial levels, with a 90% range of 1.50°C to 1.55°C — slightly higher than the 1.51°C projected in July, and effectively tied with the prior record of 1.52°C set in 2024. The analysis gives a 67% chance of a new record in the six-dataset average, and a 93% chance that 2026 will come in above 1.5°C, the second year above that level after 2024.
One caveat: the El Niño forecast for October to December lies beyond any event in the record on which the model was trained. If the warming effect of this El Niño turns out to be no larger than that of the strongest past events, the odds of a record year would be closer to 50%.
Background
The record warmth of 2026 has two ingredients: slow, human-caused warming and a short-term push from El Niño, the warm phase of the recurring El Niño-Southern Oscillation, which releases heat from the ocean into the atmosphere. As World Meteorological Organization Secretary-General Celeste Saulo told the Global Heat Forum last month, "El Niño doesn't add new heat to the planet. It releases heat the ocean has already been storing beneath the surface." That stored heat is itself the product of climate change, driven by the continued burning of fossil fuels.
Illustration: A band of exceptionally warm water stretches across the tropical Pacific during the record El Niño of 2026.
This El Niño is exceptional by every measure. In September, the daily sea surface temperature anomaly in the "Niño3.4" region, the area most widely used to gauge El Niño strength, broke the record set in November 2015 to become the strongest event since the satellite era began in 1981, and it has stayed above that record every day since. September recorded the highest monthly Niño3.4 anomaly since records began in the mid-1800s. Carbon Brief examined 656 forecasts from 14 climate models run between late September and mid-October: on average they put this year's El Niño peak at around 4°C in December, more than 1°C above the prior record. Based on tree rings and coral sediments, it may be the strongest El Niño in a millennium.
This analysis should not be confused with three different climate stories. First, it is not the Copernicus monthly bulletin in our post #873, which reported the warmest October on record from a single dataset, ERA5, and put 2026 at roughly an 80% chance of ending as the second-warmest year. Carbon Brief's quarterly update averages six datasets, gives 2026 a 67% chance of beating 2024 outright, and adds a new 2027 projection. Second, it is not the UK Met Office forecast in our post #973, which projected that carbon dioxide concentrations at Mauna Loa will rise by 3.51 parts per million in 2027 to 432.2 ppm. That story is about CO₂ concentrations; this story is about temperatures. The two share a driver, because the same El Niño is expected to weaken natural carbon sinks and push CO₂ up, but they measure different things. Third, it is not the WMO's State of the Global Climate 2025 report from March 2026 (2025 at around 1.43°C) or the BioScience 2026 State of the Climate Report in our post #179.
The datasets themselves do not agree on whether 2026 will set a record. Carbon Brief puts a 2026 record as very likely in Berkeley Earth (97%) and likely in NASA GISTEMP (82%), about as likely as not in JRA-3Q (48%) and NOAA (34%), and unlikely in ERA5 (18%). HadCRUT5 shows 72%, but that is based on data only through August; plausible September values would put its odds between around 50% and 80%. None of these datasets is "right": they differ in how they fill gaps in regions with few observations, such as the poles, and in which sea surface temperature records they use. The US National Centers for Environmental Information puts the odds far lower, at 0.1% for warmest and 86.9% for second-warmest, according to The Weather Network.
Why It Matters
The heat of 2026 was not an abstract average. Around 22% of the world's surface saw its warmest July to September on record, including much of the tropical Pacific, the western Mediterranean and Iberia, and around half of the planet experienced one of its five warmest such periods. In September alone, around 20% of the world's surface saw its warmest September on record, and 55 countries set national September records.
Illustration: Climate scientists compare six global temperature datasets to assess the 2026 record.
Western Europe had its hottest summer on record: Copernicus reported a regional average of 21.7°C, 2.5°C above the 1991–2020 average, beating the 2003 record, and a record 52% of the continent faced "very strong" heat stress. France had its warmest July on record, at 3.8°C above the 1991–2020 average. Spain had its warmest September on record, at 3.4°C above the 1991–2020 average, beating the 1987 record by 0.7°C. Elsewhere, the contiguous United States had its hottest summer and warmest September on record, with around 59% of the country in drought, while India's monsoon ended 12.6% below normal rainfall, the driest in 11 years. This year's El Niño has also suppressed Atlantic hurricanes while contributing to a record-setting number of tropical cyclones in the Pacific.
Beneath the surface temperatures lies a deeper signal: Earth's energy imbalance, the difference between energy absorbed from the sun and energy radiated back to space, has more than doubled since the start of the satellite record. NASA's CERES instruments have tracked it since March 2000: it rose from around 0.53 watts per square metre over the first decade to around 1.25 over the most recent decade, a 2.4-fold increase. While it stays positive, the Earth accumulates heat, around 90% of it in the oceans. The polar regions tell the same story: Arctic sea ice hit its annual minimum on 12 September, tied for 10th lowest on record, while Antarctic sea ice reached its winter maximum on 14 September, the third lowest behind only 2023 and 2024.
What Happens Next
The biggest temperature effect of this year's El Niño will be felt next year. Just as the 2015–16 El Niño helped make 2016 the then-warmest year on record, an event peaking around the end of 2026 will have its largest influence on global temperatures in 2027. Carbon Brief projects 2027 at around 1.74°C above pre-industrial levels (90% range 1.54°C to 1.95°C). This gives 2027 a 96% chance of being warmer than any previous year, and a 98% chance that at least one of 2026 or 2027 will set a new record. The 2027 estimate is necessarily more uncertain: none of the year has been observed yet. Carbon Brief predicts a rise of around 0.2°C between 2026 and 2027 due to El Niño, larger than the jump after any previous El Niño. Even the low end, 1.54°C, would exceed 2024; the central estimate of 1.74°C would beat it by more than 0.2°C.
The first verdicts on 2026 will arrive in January 2027, when the research groups announce their results, and they may not agree. The more important test comes later in the year, as the El Niño fades and the underlying warming trend is laid bare. The energy imbalance data suggest that trend is accelerating, and the oceans, which absorb around 90% of the extra heat, are the warmest on record. The question is no longer whether records will keep falling, but how far above 1.5°C the next one will land.
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FAQ
Is 2026 officially the warmest year on record?
Not yet. Carbon Brief gives 2026 a 67% chance of beating 2024's record in the six-dataset average, and projects the year to end at around 1.52°C above pre-industrial levels, effectively tied with 2024's record. The official verdicts will come in January 2027: a record is very likely in Berkeley Earth (97%) and likely in NASA GISTEMP (82%), but unlikely in ERA5 (18%).
How is this different from the Copernicus warmest-October report covered in post #873?
Post #873 covered a monthly bulletin from a single dataset, Copernicus ERA5, which reported the warmest October on record and put 2026 at roughly an 80% chance of ending as the second-warmest year. This article covers Carbon Brief's quarterly update, which averages six datasets, gives 2026 a 67% chance of beating 2024 outright, and adds a new 2027 projection, at around 1.7°C with a 96% chance of being the warmest year on record, which the Copernicus bulletin did not contain.
How is this different from the Met Office CO₂ forecast in post #973?
Post #973 was about carbon dioxide concentrations: the Met Office forecast that CO₂ at Mauna Loa will rise by 3.51 parts per million in 2027 to 432.2 ppm. This article is about temperatures, not CO₂ levels. The two share a driver — the same El Niño is expected to weaken natural carbon sinks and push CO₂ up — but they measure different things.
Does a year above 1.5°C mean the Paris Agreement goal has been breached?
No. Carbon Brief gives 2026 a 93% chance of ending above 1.5°C, the second year above that level after 2024, but the Paris Agreement's 1.5°C goal reflects a longer-term average, not a single year. A single hot year boosted by a strong El Niño does not by itself constitute a breach, although scientists warn the long-term average is moving steadily closer to the threshold.
Why is 2027 expected to be even hotter than 2026?
Global temperatures lag the tropical Pacific by around three months, so an El Niño peaking at around 4°C in December 2026 will have its largest effect on global temperatures in 2027. Carbon Brief projects 2027 at around 1.74°C above pre-industrial levels, with a 90% range of 1.54°C to 1.95°C, and a 96% chance of being the warmest year on record. Even the low end would exceed 2024, and there is a 98% chance that at least one of 2026 or 2027 will set a new record.
Sources
- Carbon Brief — Dr Zeke Hausfather, "State of the climate: 2026 likely to tie with 2024 as the warmest year on record", published 3 November 2026, updated 4 November 2026. https://www.carbonbrief.org/state-of-the-climate-2026-likely-to-tie-with-2024-as-the-warmest-year-on-record
- The Weather Network / CBC News — Nicole Mortillaro, "Will this year's super El Niño push 2026 to be the warmest year on record?", published 7 November 2026. https://www.theweathernetwork.com/en/news/weather/severe/will-this-years-super-el-nino-push-2026-to-be-the-warmest-year-on-record
- Carbon Brief Connect — "AMA – 5 Nov: Dr Zeke Hausfather on his latest 'state of the climate' analysis", Carbon Brief, 27 October 2026. https://connect.carbonbrief.org/t/ama-5-nov-dr-zeke-hausfather-on-his-latest-state-of-the-climate-analysis/52
- Berkeley Earth — September 2026 monthly temperature update, as reported by The Weather Network / CBC News, 7 November 2026.
- US National Snow and Ice Data Center (NSIDC) — Arctic and Antarctic sea ice extent data for September 2026, as reported by Carbon Brief, 3 November 2026.
- World Meteorological Organization — Secretary-General Celeste Saulo, remarks at the Global Heat Forum, October 2026, as reported by The Weather Network / CBC News, 7 November 2026.
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