Although 2025 did not set a new global temperature record, it still delivered clear signs of a warming planet.
According to new data released by the European Centre for Medium-Range Weather Forecasts (ECMWF), last year ranked as the third-warmest year on record globally, trailing 2024 and 2023. The global average surface air temperature was 14.97 degrees Celsius (58.95 degrees Fahrenheit). ECMWF operates the Copernicus Climate Change Service and Copernicus Atmosphere Monitoring Service.
The past 11 years have been the 11 warmest on record. But Copernicus data shows that the past three years have been especially remarkable, with nearly half of the planet experiencing annual temperatures well above average. In 2025, the global average temperature was just 0.01 degrees Celsius below 2023, the second-warmest year on record, and 0.13 degrees Celsius lower than 2024, which set an all-time high.
"Atmospheric data from 2025 paints a clear picture: human activity remains the dominant driver of the exceptional temperatures we are observing. Atmospheric greenhouse gases have steadily increased over the last 10 years," said Laurence Rouil, director of Copernicus Atmosphere Monitoring Service at ECMWF. “The atmosphere is sending us a message, and we must listen."
Global warming continues to edge closer to the 1.5-degree Celsius (2.7-degree Fahrenheit) warming limit set by the 2015 Paris Agreement, a threshold climate scientists view as critical for avoiding the worst impacts of human-amplified climate change.
For the first time, the three–year global temperature average (2023-2025) exceeded the warming threshold, according to Copernicus. While 2025 itself remained below the limit, 2024 became the first year on record to register more than 1.5 degrees Celsius warmer than the 1850-1900 pre-industrial average. In addition, nine consecutive months, from August 2024 through April 2025, individually surpassed the limit.
Although this trend is concerning, it is important to note that temporarily exceeding the threshold is not considered a failure to limit warming since climate averages are analyzed over multiple decades. However, that distinction may not hold for much longer. The UN Environment Programme warns that multi-decadal global temperature averages are likely to surpass the 1.5-degree Celsius warming threshold within the next decade, at least temporarily.
“The world is rapidly approaching the long-term temperature limit set by the Paris agreement. We are bound to pass it; the choice we now have is how to best manage the inevitable overshoot and its consequences on societies and natural systems,” said Carlo Buontempo, director of the Copernicus Climate Change Service, in a press release about the report.
Warming record could soon be challenged
While global air and sea surface temperatures are currently falling short of new record highs, climate scientists warn this pause is unlikely to last as human-caused greenhouse gas emissions continue to drive the long-term warming trend.
In 2024, global CO2 emissions hit an all-time high, rising by 3.5 parts per million (ppm) and contributing to record atmospheric CO2 levels, according to the World Meteorological Organization. That’s the most significant annual increase since modern measurements began in 1957.
A short-term drop in global temperatures was expected due to recent La Niña events in the equatorial eastern Pacific Ocean, one that ended in April 2024 and another currently underway. This climate pattern typically causes a temporary dip in average global temperatures. According to the National Oceanic and Atmospheric Administration, La Niña conditions are likely to last through early 2026.
However, the latest forecast from NOAA’s Climate Prediction Center shows that an El Niño event could unfold later this year. Record highs for global average temperature tend to occur during El Niño years, meaning the record set in 2024 could be challenged within the next few years.
Warming oceans are fueling intense hurricanes
Global daily sea surface temperatures remained above average across much of the world’s oceans last year. Between the latitudes of 60 degrees south and 60 degrees north, the average global sea surface temperature in 2025 was 69.31 degrees Fahrenheit, the third-highest value on record, according to Copernicus.
Human-amplified climate change has led to substantial ocean warming, which fuels hurricane intensification. More than 90% of the excess heat trapped by greenhouse gases has been absorbed by the oceans, creating conditions that favor rapid intensification and stronger peak winds.
The 2025 Atlantic hurricane season offers a glimpse into how human-amplified climate change could influence tropical activity in the coming decades. While the total number of tropical cyclones is expected to remain steady or even decrease slightly, the storms that do form are likely to be more intense, according to climate scientists.
Three Category 5 hurricanes formed during the past hurricane season, tying for the second-most on record in the Atlantic basin. The only other season with more Category 5 storms was 2005, when there were four.
Arctic warming faster than the global average
Sea ice coverage across the Arctic and Antarctica is a key indicator of Earth’s climate stability. In February 2025, combined sea ice extent from both poles fell to its lowest value since at least the start of satellite observations in the late 1970s. Arctic monthly sea ice extent was the lowest on record for January, February, March, and December, with the annual maximum in March also registering as the lowest on record, Copernicus reported.
The Arctic is undergoing significant changes, with cascading impacts felt worldwide. The region is warming much faster than the global average, with autumn and winter air temperatures rising more than twice as fast over the past two decades. The persistent warming trend has contributed to declining snow cover and a shortening snow season. June snow cover extent over the Arctic has declined by about 50% on average since 1967, according to NOAA’s 2025 Arctic Report Card.
Loss of snow and ice cover reduces the Arctic’s ability to reflect incoming sunlight, disrupting Earth’s energy balance. “The loss of reflective snow surfaces in June, when incoming solar energy reaches its annual peak, results in more heat absorbed at the surface, contributing as a feedback to Arctic warming,” said Gerald (J.J.) Frost, senior scientist with Alaska Biological Research, Inc. and veteran Arctic Report Card author.
Reduced snow cover not only promotes further warming but also increases the wildfire threat in the region. These compounding factors create a self-reinforcing cycle, amplifying global warming and making it increasingly difficult to reduce carbon dioxide emissions.
For thousands of years, the vast Arctic tundra acted as an essential carbon sink, providing a net removal of this heat-trapping greenhouse gas from the atmosphere. However, in 2024, NOAA revealed a startling shift, explaining that rapidly warming conditions and rising wildfire activity are turning the region into a source of carbon dioxide emissions.
Ongoing glacier loss is driving steadily rising global sea levels, putting Arctic communities’ water supplies at risk, fueling destructive floods, and increasing landslide and tsunami hazards that threaten people, infrastructure, and coastlines, according to NOAA.
Ozone layer’s recovery shows we can make a difference
Amid ongoing climate challenges, the recovery of the ozone layer stands as powerful evidence that global action can deliver measurable results. According to a report released in November by NOAA and NASA scientists, the Antarctic ozone hole in 2025 ranked as the fifth smallest since 1992, highlighting the significant impact of global efforts to limit ozone-depleting chemicals.
The so-called “ozone hole” is not an actual hole in the planet’s ozone layer, but rather a large region of the stratosphere with extremely low ozone concentrations. For decades, chlorofluorocarbons (CFCs) and other ozone-depleting compounds were widely used in aerosol sprays, foams, air conditioners, and refrigerators, causing significant reductions in ozone levels. Natural factors, such as temperature and atmospheric circulation, also influence ozone concentrations and likely contributed to the smaller ozone hole last year, according to researchers.
Regulations established by the Montreal Protocol, which went into effect in 1992, have driven the gradual recovery of the ozone layer. It remains on track to fully recover later this century as countries worldwide replace harmful substances with safer alternatives.
Earth’s ozone layer acts as a planetary sunscreen, shielding humans, animals, and plants from harmful ultraviolet (UV) radiation. When ozone levels drop, more UV rays reach the surface, increasing the risk of adverse health and environmental impacts such as crop damage, skin cancer, and cataracts.
“This year’s hole would have been more than one million square miles larger if there was still as much chlorine in the stratosphere as there was 25 years ago,” said Paul Newman, senior scientist at the University of Maryland system and longtime leader of NASA’s ozone research team, when the report was released.