According to ECMWF, the planet has for the first time marked a three-year period during which the average temperature has been 1.5 degrees Celsius above the pre-industrial era level, the limit beyond which scientists warn that global warming will cause severe consequences, some of them irreversible.
The planet experienced its third-hottest year on record in 2025, with global average temperatures exceeding the 1.5 degree Celsius mark for three consecutive years, the longest period since records began, European Union scientists said on Wednesday. Data from the European Centre for Medium-Range Weather Forecasts (ECMWF) showed the past three years were the planet’s warmest on record, with 2025 only slightly cooler than 2023, by just 0.01 degrees Celsius. Britain’s National Weather Service confirmed that 2025 was the third-hottest year on record since records began in 1850. The World Meteorological Organization is expected to release its figures later on Wednesday.
According to ECMWF, the planet has for the first time marked a three-year period during which the average temperature has been 1.5 degrees Celsius above the pre-industrial era level, the limit beyond which scientists warn that global warming will cause severe consequences, some of them irreversible.
“1.5 degrees Celsius is not an immediate catastrophe threshold. However, we know that every fraction of a degree matters, especially in terms of worsening extreme cold events,” said Samantha Burgess, climate strategy leader at ECMWF. Governments pledged under the 2015 Paris Agreement to try to avoid global warming exceeding 1.5 degrees Celsius, measured as a long-term average compared to the pre-industrial era. But failure to reduce greenhouse gas emissions means that level could be exceeded before 2030, a decade earlier than predicted when the agreement was signed, ECMWF said.
“We are destined to cross this threshold,” said Carlo Buontempo, director of the EU’s Copernicus Climate Change Service. “The choice we have now is how best to manage the inevitable crossing and its consequences for societies and natural systems.”
Currently, the long-term rate of global warming is about 1.4 degrees Celsius above pre-industrial levels, according to the ECMWF. Measured in the short term, the world has already surpassed the 1.5 degrees Celsius threshold in 2024. In 2025, wildfires in Europe produced the highest level of emissions ever recorded, while scientific studies have confirmed that some specific weather events have been exacerbated by climate change – including Hurricane Melissa in the Caribbean and monsoon rains in Pakistan, which killed more than 1,000 people in floods.
Despite these growing consequences, climate science is facing increasing political resistance. US President Donald Trump, who has called climate change “the greatest hoax,” last week withdrew from dozens of UN organizations, including the Intergovernmental Panel on Climate Change. The long-standing consensus among scientists around the world is that climate change is real, largely caused by human activity, and that the situation is getting worse. The main cause is greenhouse gas emissions from the burning of fossil fuels such as coal, oil and gas, which trap heat in the atmosphere.