2025 among world’s three hottest years on record, WMO says

By Kate Abnett

BRUSSELS, Jan 14 (Reuters) – Last year was one of the three hottest on record on the planet, the World Meteorological Organization said on Wednesday, as EU scientists also confirmed that average temperatures have now exceeded 1.5 degrees Celsius of global warming for the longest period since records began.

The WMO, which consolidates eight climate data sets from around the world, said six of them – including the European Union’s European Center for Medium-Range Weather Forecasts (ECMWF) and Britain’s National Weather Service – ranked 2025 as the third warmest year, while two of them placed it second in 176 years.

The US National Oceanic and Atmospheric Administration also confirmed in data released Wednesday that 2025 was the third warmest year in its global temperature record, which dates back to 1850.

The eight data sets confirmed that the past three years were the planet’s three warmest years since records began, the WMO said. The hottest year on record was 2024.

THREE-YEAR PERIOD ABOVE 1.5 C AVERAGE WARMING LEVEL

The slight differences in the ranking of the datasets reflect their different methodologies and measurement types, which include satellite data and weather station readings.

ECMWF said 2025 also marked the first three-year period in which the global average temperature was 1.5°C higher than in the pre-industrial era – the limit beyond which scientists expect global warming to have serious consequences, some of them irreversible.

“1.5°C is not a cliff. However, we know that every fraction of a degree counts, particularly as extreme weather events worsen,” said Samantha Burgess, strategic climate manager at ECMWF.

Burgess said she expected 2026 to be one of the five hottest years on Earth.

CHOICE OF HOW TO MANAGE TEMPERATURE EXCEEDING

Governments committed under the 2015 Paris Agreement to try to avoid exceeding 1.5°C of global warming, measured as an average temperature over several decades compared to pre-industrial temperatures.

But their failure to reduce greenhouse gas emissions means that target could now be exceeded before 2030 – a decade earlier than expected when the Paris agreement was signed in 2015, ECMWF said.

“We are obliged to adopt it,” said Carlo Buontempo, director of the EU’s Copernicus climate change service. “The choice now before us is how best to manage the inevitable overshoot and its consequences for societies and natural systems.”

Currently, the long-term level of global warming is about 1.4°C higher than in the pre-industrial era, ECMWF said. Measured in the short term, average annual temperatures exceeded 1.5°C for the first time in 2024.

NOAA said 2025 exceeded the pre-industrial average by 1.34°C, or 2.41°F.

The US agency also said the heat content of the upper oceans reached a record high in 2025, indicating that Earth’s oceans have reached their highest levels of heat, leading to stronger storms, heavier precipitation and rising sea levels.

EXTREME WEATHER

Exceeding the long-term limit of 1.5°C would lead to more extreme and widespread consequences, including hotter and longer heat waves, as well as more powerful storms and floods.

Already in 2025, wildfires in Europe have produced the highest total emissions on record, while scientific studies have confirmed that specific weather events have been made worse by climate change, including Hurricane Melissa in the Caribbean and monsoon rains in Pakistan that killed more than 1,000 people in floods.

Despite these worsening impacts, climate science faces political resistance. US President Donald Trump, who has called climate change “the biggest scam”, last week withdrew from dozens of UN entities, including the Intergovernmental Scientific Panel on Climate Change.

The long-standing consensus among scientists around the world is that climate change is real, primarily caused by humans, and that it is getting worse. Its main cause is greenhouse gas emissions from the burning of fossil fuels like coal, oil and gas, which trap heat in the atmosphere.

(Reporting by Kate Abnett and Valerie Volcovici; additional reporting by William James and Emma Farge; editing by Alison Williams, Alexandra Hudson)