What happened
The Copernicus Climate Change Service says 2026 could end as one of the two warmest years in the observational record. It estimates a 20% probability that the year will move ahead of 2024.
For the October cited in the assessment, global mean temperature was 1.75°C higher than the October average for 1850–1900. Copernicus also reported that the global average had remained above 1.5°C relative to that reference period for three successive months.
In a separate forecast, the UK Met Office expects atmospheric carbon dioxide to reach 432.2 ± 0.5 parts per million in 2027. The forecast implies an annual increase of 3.51 ± 0.52 ppm.
Why it matters
The two assessments underline the interaction between warming conditions and the capacity of land ecosystems to absorb carbon dioxide. The Met Office links part of the expected CO2 increase to El Niño-associated heat and drought, which can reduce carbon uptake by forests and other vegetation.
For sustainability and risk teams, the forecasts are relevant context for monitoring physical climate exposure and assumptions about the resilience of natural carbon sinks. The material does not set out a new policy, reporting duty or compliance deadline.
Role of El Niño
Copernicus identifies an exceptionally strong El Niño as a major influence on the temperature outlook for 2026. The Met Office similarly points to warmer and drier conditions in Central America, the western Pacific and tropical South America as factors that could constrain vegetation uptake of atmospheric CO2.
According to the Met Office estimate, annual CO2 growth in 2027 would be 2.57 ppm without the El Niño effect, rather than 3.51 ppm. The forecast therefore attributes 0.94 ppm of the projected rise to that influence.
What to watch
The final position of 2026 in the global temperature record will depend on observations across the full year. The Met Office CO2 projection concerns the atmospheric concentration expected in 2027; readers should track subsequent observations against that forecast and developments affecting terrestrial carbon uptake.
