Six international science and weather institutions have separately found that 2024 was the hottest year on record, the World Meteorological Organisation (WMO) said today.
The organisations co-ordinated to release their 2024 average temperature data on the same day, "to underline the exceptional conditions experienced during 2024," the WMO said.
The WMO uses data from the six agencies — the UK's Met Office, Japan's Meteorological Agency (JMA), US non-profit Berkeley Earth, the EU's Copernicus and the US' National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (Nasa).
The global average surface temperature in 2024 was 1.55°C above the pre-industrial average, with a margin of uncertainty of 0.13°C either above or below that figure, WMO found in its analysis of the six datasets. This makes it "likely" that the world has experienced the first calendar year breaching the 1.5°C limit pursued by the Paris climate accord. Climate scientists use a timeframe of 1850-1900 for the pre-industrial average temperature. The Paris agreement seeks to limit global heating to "well below" 2°C above pre-industrial levels, and preferably to 1.5°C.
All six datasets put 2024 as the hottest year on record and flag up the recent rate of warming, but "not all show the temperature anomaly above 1.5°C due to differing methodologies," WMO said. Copernicus found the global average temperature in 2024 was 1.6°C above pre-industrial levels.
"Individual years pushing past the 1.5°C limit do not mean the long-term goal is shot," UN secretary-general Antonio Guterres said. "There's still time to avoid the worst of climate catastrophe. But leaders must act — now."
He urged governments to submit new national climate action plans this year.
The temperature limits sought by the Paris agreement work on a timeframe of 20 years or longer, Copernicus said. Long-term global warming is currently about 1.3°C above the pre-industrial baseline, a team of experts established by WMO found.
"We've had not just one or two record-breaking years, but a full 10-year series," said WMO secretary-general Celeste Saulo. "This has been accompanied by devastating and extreme weather, rising sea levels and melting ice, all powered by record-breaking greenhouse gas levels due to human activities."
The UK Met Office outlook finds that 2025 is likely to be one of the three warmest years, in terms of global average temperature, "falling in line just behind 2024 and 2023", it said today.