Even so, the past three years together still represent the warmest period ever recorded globally.

The figures underline a worrying reality. Despite temporary natural cooling, the planet continues to warm at a pace that brings it increasingly close to breaching internationally agreed climate limits. Scientists stress that temperatures in 2025 were still far higher than those recorded even a decade ago, reflecting the continued impact of human-driven carbon emissions.

Experts warn that without sharp and sustained cuts to greenhouse gas emissions, new temperature records and more intense weather extremes are inevitable.

“If we look back from twenty years in the future, the mid-2020s will probably appear relatively cool,” said Dr Samantha Burgess, deputy director of the Copernicus climate service, highlighting the long-term trajectory of global warming.

According to combined Copernicus and Met Office data, the global average temperature in 2025 stood more than 1.4°C above pre-industrial levels from the late nineteenth century, before large-scale fossil fuel use began. While precise estimates vary slightly between major climate research groups due to differences in how pre-industrial baselines are calculated, scientists are united in their assessment that the world is undergoing sustained and accelerating warming.

Prof Rowan Sutton, director of the Met Office Hadley Centre, said the underlying mechanism is well understood. As greenhouse gases continue to accumulate in the atmosphere, the Earth retains more heat, leading to rising global temperatures.

Although 2025 was not the hottest year on record, extreme weather events linked to climate change continued across the globe. Wildfires in Los Angeles early in the year and Hurricane Melissa in October were among the events that researchers say were intensified by a warming climate. Warmer oceans and atmosphere mean storms such as Melissa can produce heavier rainfall and stronger winds, contributing to severe flooding and widespread damage, including in parts of the Caribbean such as Haiti.

The sustained warmth has also brought the world closer to exceeding the 1.5°C temperature threshold set under the 2015 Paris Agreement, signed by nearly 200 countries to limit the most dangerous impacts of climate change. That target was designed to reduce the risk of more severe consequences expected at 2°C of warming.

“Based on current trends, it appears increasingly likely that we will pass the 1.5 degree level of long-term warming by the end of this decade,” Burgess said.

While long-term warming is clearly driven by human activity, year-to-year temperature variations are influenced by natural climate cycles. One of the most significant is the shift between El Niño and La Niña conditions in the Pacific Ocean. El Niño years tend to raise global average temperatures, while La Niña usually has a cooling effect.

El Niño contributed to the exceptional heat recorded in 2023 and especially 2024. The return of La Niña in 2025 is thought to have dampened temperatures slightly. However, the fact that global temperatures remained so high during a La Niña year has concerned scientists.

Dr Zeke Hausfather, a climate scientist at Berkeley Earth, said the persistence of such warmth under typically cooler conditions was “a little worrying”.

Data from Copernicus show that global temperature records for individual months have repeatedly been broken since 2023. This sharp rise surprised many researchers and prompted debate about whether additional factors might be amplifying warming, alongside greenhouse gas emissions and natural climate cycles. Possible contributors include changes in cloud cover and reductions in atmospheric aerosols, which may be reflecting less solar energy back into space.

The continuation of unusually high temperatures into 2025 suggests there may still be aspects of the climate system that are not fully understood, Hausfather noted. Sutton agreed, saying recent warming appears to be at the upper end of long-term projections, though more data is needed before drawing firm conclusions about lasting implications.

The findings have been widely reported, including by the BBC, as scientists emphasise that while rising temperatures are a serious warning sign, the future is not predetermined.

“We still have agency,” Sutton said. “By cutting emissions we can slow and stabilise warming, and by adapting we can make societies more resilient to the changes that are already under way.”