The Earth recorded its third hottest year in 2025, marking an unbroken sequence of exceptional heat that scientists warn shows no sign of abating in 2026, according to data released Wednesday by United States researchers and European Union climate monitors.
The last 11 years now stand as the warmest ever documented in human history, with 2024 claiming the top position and 2023 in second place, according to findings published by the EU’s Copernicus Climate Change Service and Berkeley Earth, a California-based non-profit research organisation specialising in climate analysis.
In a development that underscores the accelerating pace of planetary warming, global temperatures exceeded the critical 1.5 degrees Celsius threshold relative to pre-industrial levels on average over the last three years for the first time, Copernicus said in its annual report. The finding represents a sobering milestone in humanity’s struggle to contain the effects of climate change and raises urgent questions about the viability of international climate targets.
“The warming spike observed from 2023-2025 has been extreme, and suggests an acceleration in the rate of the Earth’s warming,” Berkeley Earth said in a separate report released alongside the Copernicus findings.
Temperatures stood at 1.47C above pre-industrial times in 2025—just marginally cooler than in 2023—following 1.6C in 2024, according to the EU climate monitor. The consistency of these elevated readings reflects a sustained departure from historical temperature patterns that scientists attribute primarily to the accumulation of greenhouse gases in the atmosphere from human activity.
The landmark 2015 Paris Agreement, adopted by nearly 200 countries at the United Nations climate conference in France, commits the world to limiting warming to well below 2C and pursuing efforts to hold it at 1.5C—a long-term target scientists say would help avoid the worst consequences of climate change, including catastrophic sea-level rise, devastating droughts, and the collapse of critical ecosystems.
UN Secretary-General António Guterres warned in October that breaching the 1.5C limit was “inevitable” but emphasised that the world could limit this period of overshoot by cutting greenhouse gas emissions as quickly as possible. The statement reflected growing recognition among climate officials and scientists that the Paris Agreement’s most ambitious goal may slip out of reach sooner than anticipated.
Copernicus said the 1.5C limit “could be reached by the end of this decade—over a decade earlier than predicted,” a revision that has alarmed climate researchers and policymakers who view the target as a crucial guardrail against runaway warming.
Efforts to contain global warming suffered another significant setback last week when President Donald Trump announced he would pull the United States—the world’s second-biggest polluter after China—out of the bedrock UN climate treaty. The move, which echoes Trump’s first-term withdrawal from the Paris Agreement, has raised concerns about the erosion of international cooperation on climate action at a moment when scientists say decisive intervention is most critical.
The human toll of rising temperatures was starkly illustrated in Berkeley Earth’s findings, which showed that some 770 million people experienced record-warm annual conditions where they live in 2025, while no record-cold annual average was logged anywhere on Earth. The statistic underscores the global and asymmetric nature of climate change, which is disproportionately affecting vulnerable populations in regions least equipped to adapt.
The Antarctic experienced its warmest year on record while it was the second hottest in the Arctic, Copernicus said, pointing to particularly acute warming in the polar regions that scientists consider bellwethers of broader climate trends. The melting of ice sheets and glaciers in these regions contributes directly to sea-level rise and disrupts ocean circulation patterns with far-reaching consequences for global weather systems.
An analysis of Copernicus data conducted by Agence France-Presse last month found that Central Asia, the Sahel region, and northern Europe experienced their hottest year on record in 2025, illustrating the varied regional impacts of global warming. These findings align with long-standing scientific projections that certain areas would experience more pronounced warming than the global average, with landlocked continental regions and high-latitude zones particularly vulnerable.
Berkeley Earth and Copernicus both warned that 2026 would not break the troubling trend of escalating temperatures. If the warming El Niño weather phenomenon appears this year, “this could make 2026 another record-breaking year,” Carlo Buontempo, director of the Copernicus Climate Change Service, told AFP.
“Temperatures are going up. So we are bound to see new records. Whether it will be 2026, 2027, 2028 doesn’t matter too much. The direction of travel is very, very clear,” Buontempo said, emphasising the inexorable nature of the warming trajectory absent dramatic intervention.
Berkeley Earth said it expected this year to be similar to 2025, “with the most likely outcome being approximately the fourth-warmest year since 1850,” when reliable global temperature records began. The projection suggests that even in the absence of El Niño conditions, which typically boost global temperatures, the baseline warming trend is sufficient to keep 2026 among the hottest years ever documented.
The reports arrive at a moment when efforts to cut greenhouse gas emissions—the main driver of climate change—are stalling in developed countries that have historically been responsible for the largest share of cumulative emissions. Emissions rose in the United States last year, snapping a two-year streak of declines, as bitter winters and the artificial intelligence boom fuelled demand for energy, the Rhodium Group think tank said Tuesday. The pace of reductions in greenhouse gas emissions also slowed in Germany and France, two major European economies that have positioned themselves as leaders in climate action.
“While greenhouse gas emissions remain the dominant driver of global warming, the magnitude of this recent spike suggests additional factors have amplified recent warming beyond what we would expect from greenhouse gases and natural variability alone,” said Robert Rohde, chief scientist at Berkeley Earth.
The organisation identified international rules cutting sulfur in ship fuel since 2020 as a potential contributing factor. Paradoxically, these regulations, designed to reduce air pollution, may have actually added to warming by reducing sulfur dioxide emissions, which form aerosols that reflect sunlight away from Earth. The finding illustrates the complex interplay of human activities and climate systems, where well-intentioned environmental regulations can produce unexpected consequences.
The acceleration of warming over the past three years has prompted renewed scientific scrutiny of climate models and feedback mechanisms. Some researchers have pointed to the possibility that the Earth system may be crossing thresholds that trigger self-reinforcing warming cycles, such as the release of methane from thawing permafrost or the reduction of the planet’s albedo—its reflectivity—as ice sheets shrink and darker ocean and land surfaces absorb more solar radiation.
The history of global climate monitoring stretches back to the mid-19th century, but the systematic collection of comprehensive temperature data accelerated dramatically in the satellite era beginning in the 1970s. The Copernicus Climate Change Service, operated by the European Centre for Medium-Range Weather Forecasts, has become one of the world’s most authoritative sources of climate data, combining satellite observations, ground-based measurements, and sophisticated modelling techniques to produce detailed assessments of planetary conditions.
Berkeley Earth, founded in 2010, emerged from efforts to address skepticism about the reliability of temperature records by conducting independent analysis of raw climate data. The organisation’s findings have consistently aligned with those of other major climate monitoring institutions, including NASA, the US National Oceanic and Atmospheric Administration, and the UK Met Office, lending credibility to the scientific consensus on global warming.
The implications of the continued warming extend far beyond abstract temperature statistics. Rising global temperatures are already manifesting in more frequent and severe heatwaves, intensified droughts and flooding, the bleaching of coral reefs, shifts in agricultural productivity, and the forced migration of human populations from increasingly uninhabitable regions. Public health officials warn of expanding disease vectors, reduced air quality, and heightened risks for vulnerable populations including the elderly and those with pre-existing health conditions.
