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2025 is on course to be the second or third warmest year ever recorded.
The 2023–2025 period may temporarily exceed the 1.5°C global warming limit.
Scientists report an unprecedented 0.4°C temperature jump in just two years.
Recent warming cannot be fully explained by El Niño or reduced aerosols.
Research suggests the world may be entering a new climate era above 1.5°C.
Global warming has accelerated so rapidly since 2023 that temperatures in 2025 are poised to challenge historic records, raising concerns that the world is moving into a long-term breach of the 1.5 degrees Celsius (°C) threshold. 2025 is on track to become the second or third warmest year on record, shows the latest update from the Copernicus Climate Change Service (C3S), while the three-year period from 2023 to 2025 could be the first to exceed the 1.5°C warming limit above the pre-industrial average (1850-1900).
The sequence of record-breaking annual and monthly temperatures that began in June 2023 has continued into November 2025, which ranked as the third warmest November on record. “The global average temperature anomaly for January to November 2025 stands at 0.60°C above the 1991-2020 average, or 1.48°C above the 1850-1900 pre-industrial reference,” C3S stated. This anomaly is comparable to that recorded for the whole of 2023, the second warmest year on record.
World Meteorological Organization (WMO) data shows that 2023 was 1.45°C warmer than the pre-industrial average. According to C3S, the global annual average temperature anomaly for that year was 1.48°C.
Based on WMO figures, which is an average of six international datasets, the anomaly in 2023 represented a striking rise of 0.3°C from 2022, when the global annual average anomaly stood at 1.15°C. In previous years, changes had been far smaller, with only a 0.05°C increase between 2021 and 2022.
Between 2021 and 2023, the difference in global annual average temperatures reached 0.35°C. In 2020, the previous warmest year on record, the anomaly was 1.2°C — meaning the jump to 2023 amounted to 0.25°C. From June 2023 to June 2024, the world also recorded 13 consecutive months of all-time monthly temperature highs.
The warming trend continued into 2024, the first year in which the global annual average temperature anomaly exceeded the 1.5°C threshold. The WMO estimated that 2024 was 1.55°C warmer than the pre-industrial baseline. The warmest day ever recorded also occurred that year on July 22, 2024, when the daily global average temperature reached 17.16°C.
In 2025, the pattern persisted, with the first month of the year becoming the warmest January on record — despite the presence of a La Niña climate phenomenon in the equatorial Pacific, which typically has a cooling influence on global temperatures. Several other months ranked second, third or fourth for their respective temperature anomalies. June to October 2025 were all the third warmest on record, while March to May were the second warmest. February 2025 ranked third.
A research paper published in February 2025 in the journal Environment: Science and Policy for Sustainable Development examined the acceleration of global warming and its implications. The team was led by James Hansen, director of the climate science, awareness and solutions programme at the Earth Institute, Columbia University, and one of the world’s foremost climate scientists.
Global warming has accelerated by more than 50 per cent since 2010 compared with the rate observed between 1970 and 2010, when temperatures rose at 0.18°C per decade, the study found. This trend had already been noted by the Intergovernmental Panel on Climate Change (IPCC) in its Sixth Assessment Report (AR6). But since the AR6 Synthesis Report was released in March 2023, warming has steepened dramatically and the situation appears alarming.
According to the paper, the past two years (2023-2024) saw a temperature spike of 0.4°C in the global averages. The 2023-2024 El Niño event, along with reduced aerosol pollution from shipping, could not fully explain the magnitude of the increase. The authors noted that the 12-month average global temperature anomaly peaked in August 2024 at 1.6°C above the temperature at the start of the 20th century.
The researchers wrote that “this temperature jump was spurred by one of the periodic tropical El Niño warming events, but many Earth scientists were baffled by the magnitude of the global warming, which was twice as large as expected for the weak 2023-2024 El Niño”.
November 2025, with a temperature anomaly of 1.54°C above the pre-industrial average, reinforces the pattern of record global temperatures — suggesting that the world may be entering the early stages of surpassing the long-term 1.5°C threshold established under the Paris Agreement.
While a single year, or even three consecutive years, above 1.5°C does not constitute a formal breach of the threshold, research indicates that the extreme warming observed in 2023 and 2024 may mark the onset of its long-term exceedance. The WMO and the IPCC assess threshold breaches using datasets covering at least 20 years.
A study published on February 10, 2025 in the journal Nature Climate Change by researchers Emanuele Bevacqua and Jakob Zscheischler of the Helmholtz Centre for Environmental Research, Leipzig, and Carl-Friedrich Schleussner of the International Institute for Applied Systems Analysis, Austria, argues that “without very stringent climate mitigation, the first year above 1.5 °C occurs within the first 20-year period with an average warming of 1.5 °C”.
This implies that the world is likely to experience sustained warming of at least 1.5°C over the next two decades. It suggests that 2024 was not an anomaly, but the beginning of a new climatic era in which global average temperatures remain consistently above the 1.5°C threshold.