Where the temperature is
The 1.5°C figure in the Paris Agreement is a long-term average above the 1850–1900 baseline, so a single hot month does not breach it. The recent record is nonetheless close to the line. Copernicus put 2025 at 1.47°C above pre-industrial, slightly cooler than 2024 and level with 2023. The World Meteorological Organization, using a blend of datasets, gave a lower figure of about 1.43–1.44°C and called 2025 one of the three warmest years on record.1 The three years 2023 to 2025 averaged more than 1.5°C, the first three-year period to do so, according to Copernicus.2
2026 looks warmer. Copernicus reports that September was 1.63°C above pre-industrial, the second-warmest September on record and the second month in a row above 1.5°C, after August tied the hottest month on record. Averaged over January to September, 2026 ranks second, behind 2024 and ahead of 2023 and 2025. Sea surface temperature outside the polar regions set a new record in September.3 The reason is a rapidly strengthening El Niño. The WMO's seasonal update forecasts the Niño 3.4 anomaly to reach about 3.6°C, with the event peaking in November to December, and Copernicus expects the run of months above 1.5°C to continue into 2027.4 A Carbon Brief analysis in July put the chance that 2026 beats 2024 as the warmest year at about 35%, but that was before the latest monthly data.5
What is driving it
Greenhouse gases keep rising. Carbon dioxide at Mauna Loa averaged 432 ppm in May 2026, up 1.8 ppm in a year, according to Scripps and NOAA.6 The WMO's State of the Global Climate 2025, published in March, reports that carbon dioxide, methane and nitrous oxide are at their highest levels in at least 800,000 years. It also adds Earth's energy imbalance as a headline indicator and finds the planet more out of balance than at any time in the record. Ocean heat content reached a new high in 2025, and sea-level rise has sped up, from 2.65 mm a year in 1993–2011 to 4.75 mm a year in 2012–2025.7
The latest attribution work, the annual Indicators of Global Climate Change assessment, estimated that 2024's observed warming of 1.52°C included about 1.36°C caused by human activity. It put the remaining carbon budget for a 50% chance of holding 1.5°C at roughly 130 billion tonnes of CO₂ from the start of 2025, a little over three years at current emissions.8
Where policy is heading
UNEP's Emissions Gap Report 2025 projects about 2.8°C of warming by 2100 on current policies and 2.3–2.5°C if every national pledge is fully met. Those are improvements on the previous year (3.1°C and 2.6–2.8°C), but UNEP attributes about 0.1°C of the change to methodology and says the US exit from the Paris Agreement offsets another 0.1°C. It says that a temporary overshoot of 1.5°C is now very likely within the next decade, though returning below it by 2100 remains possible. Holding 2°C needs emissions about 35% below 2019 levels by 2035, and 1.5°C needs about 55%.9
The COP30 summit in Belém in November 2025 ended without a formal roadmap away from fossil fuels. Brazil's presidency said it would bring forward voluntary roadmaps on fossil fuels and deforestation, and a coalition of more than 80 countries committed to pursue reductions outside the formal process. Countries agreed to a goal of tripling adaptation finance by 2035 and reaffirmed the $300 billion a year climate-finance target agreed at COP29.10 Separately, the International Court of Justice found unanimously in July 2025, in an advisory opinion, that states have binding obligations to protect the climate system, owed to the international community as a whole, and that breaching them can engage state responsibility.11
Is it existential?
Not in the sense the word usually implies. None of the sources above projects human extinction from warming at these levels. The case for treating it as a civilisational risk is about direction and irreversibility. Some thresholds in the Earth system may already be crossed, and the correlated failures of food production that higher warming makes more likely would hit societies at the same time. The companion article sets out where that evidence is firm and where it is not.
What the numbers do show is a gap. The world is at about 1.4–1.5°C now. The pledges it has made lead to roughly 2.3–2.5°C. The remaining budget for 1.5°C is a few years of emissions. And the next two years will be unusually hot for natural reasons, which will make the trend easier to misjudge in both directions.