2025 was the third-warmest year on record

In a stark reminder of the accelerating pace of global warming, the latest Copernicus Climate Change Service report has confirmed that 2025 was the third-warmest year on record, continuing a multi-decade trend of rising temperatures driven by human activity.

Copernicus is the European Union’s Earth observation programme that provides free, open data and services about the planet’s environment, using satellites and ground sensors to monitor climate, land, oceans, atmosphere and security.

The findings, unveiled this week by the European Centre for Medium-Range Weather Forecasts (ECMWF), paint a picture of a planet that is rapidly heating, with far-reaching implications for ecosystems, economies and human health.

According to the report, global average surface temperatures in 2025 were approximately 1.47°C above pre-industrial levels, measured against the 1850–1900 baseline commonly used by climate scientists.

That number places 2025 behind only 2024 and 2023 in the modern record books, with 2025’s annual mean 0.13°C cooler than 2024 and just 0.01°C cooler than 2023.

While these global figures are fractions of a degree, scientists stress they represent a profound shift in Earth’s climate system.

Over the past decade, every year has ranked among the warmest in modern history, and the last three years (2023–2025) have, on average, exceeded 1.5°C above pre-industrial levels, marking the first time such a three-year period has sustained this level of warming.

“This report confirms that Europe and the world are in the warmest decade on record,” said Florian Pappenberger, Director-General of the ECMWF, during the releasing of the report. 

Heat on land, heat at sea

The Copernicus findings spotlight not just elevated global averages, but widespread heat anomalies across land and sea.

In Antarctica, 2025 recorded its warmest annual temperatures on record, while the Arctic experienced its second-warmest year, with consequential reductions in sea ice extent. Global sea-surface temperatures also ranked among the highest ever recorded.

Regions from Central Asia and northern Europe to parts of the Pacific and Atlantic saw record-breaking annual temperatures, illustrating the global reach of the warming trend.

Even in tropical zones, where some natural variability traditionally tempers heat, surface air temperatures remained far above historical averages, said the ECMWF.

On land, the impacts were tangible, with many parts of the world enduring more frequent and intense heat waves, contributing to heat stress conditions that exceeded historical norms.

According to health agencies, high “feels-like” temperatures, above 32°C, affected vast swaths of the global population, exacerbating risks to vulnerable communities and stressing energy, water and health systems.

Beyond the numbers: ecosystems, economies and people

The Copernicus report dovetails with warnings from climate experts worldwide who have suggested that the rise in average temperatures is intensifying extreme weather, shifting rainfall patterns and threatening biodiversity.

“Atmospheric data from 2025 paints a clear picture: human activity remains the dominant driver of the exceptional temperatures we are observing,” said Laurence Rouil, Director of the Copernicus Atmosphere Monitoring Service.

Rampant greenhouse gas emissions, especially carbon dioxide and methane from fossil fuels, have steadily accumulated in the atmosphere, trapping more heat and amplifying warming trends with each passing year, reads the report.

The consequences are not abstract. Wildfires have increased in frequency and severity, with major blazes recorded in Europe, North America and Australia.

Heat-related deaths, particularly among older adults, outdoor workers and communities without reliable cooling infrastructure, have climbed.

Crops in many regions are under stress from drought and temperature extremes, raising concerns about food security. Coastal communities confront rising seas and more destructive storms as ocean temperatures climb.

Paris Agreement goals slipping out of reach?

The data’s broader context also underscores the challenge facing international climate policy. When world leaders agreed to the Paris Agreement in 2015, they pledged to limit global warming to well below 2°C above pre-industrial levels, and to pursue efforts to keep it no more than 1.5°C.

Yet, the sustained warmth of the past three years, and the climbing trajectory of greenhouse gas emissions, suggest that even the 1.5°C threshold may be breached for multi-year averages imminently, likely before the end of this decade, the report has warned.

The Copernicus report is not just a retrospective. It’s a warning. The pace of warming reflects a climate already transformed by human activity, and without rapid, sustained cuts in emissions, the world will continue to see more years like 2025, or hotter.

For policymakers, the message is clear. As Pappenberger concluded, “preparedness and prevention remain possible but only when action is guided by robust, scientific evidence.”

• Dr Enock Sithole is the executive director of the Institute for Climate Change Communication.