Global temperature records that once seemed distant are now falling in quick succession, and 2025 has pushed the climate system into territory many researchers long hoped never to see. Multiple scientific teams now agree that last year ranked among the three hottest ever measured, even though natural cycles should have nudged the planet slightly cooler.
In that context, several leading climatologists argue that keeping warming below 1.5°C is no longer a realistic outcome, not a worst-case scenario to be avoided. The data behind that warning, from detailed global analyses to satellite records and ocean measurements, show a world that has decisively crossed into a new thermal regime.
Third‑warmest year, in a decade of extremes
Global monitoring agencies now converge on the same stark conclusion, that 2025 was Earth’s third‑warmest year on record, behind only 2024 and 2023. A comprehensive global report of temperatures and other climate indicators shows that the planet’s surface was significantly hotter than the late twentieth‑century baseline. Parallel work from Berkeley Earth reaches the same ranking, based on independent processing of land and ocean thermometer records.
In its own Assessing the Global, the Annual Highlights from NOAA describe 2025 as the third‑warmest year in a record that stretches back to the nineteenth century. A companion analysis from the same Berkeley Earth team concludes that 2025’s heat is robust across different datasets, including measurements collected by ships and buoys that track ocean conditions.
La Niña could not cool a warming planet
What makes 2025 stand out is not only how hot it was, but when it arrived in the natural climate cycle. Unlike 2023 and 2024, which were El Niño years, 2025 began and ended with a modest La Niña event, a pattern that typically brings some global cooling. The European Copernicus Climate both highlight that context, noting that such warmth during La Niña underscores the strength of human‑driven warming. A detailed discussion of these natural cooling patterns notes that, despite them, global temperatures remained near the highest levels directly observed using thermometer measurements.
That disconnect between expected cooling and observed heat is central to the warning scientists are now issuing. In the broader NOAA overview of global climate conditions, the agency notes that 2025’s warmth came despite the presence of La Niña, which historically has pulled annual averages downward. A separate assessment of how warm 2025 was, compiled using Copernicus data, stresses that several regions still stood out for their extremes, from marine heatwaves to record‑breaking land temperatures.
How hot is “too hot” for the Paris targets?
For years, the 1.5°C threshold in the Paris Agreement has been treated as a political and scientific north star, a level of warming that would sharply limit the most dangerous impacts. The latest Global Climate Highlights show that the global average temperature in 2025 was 14.97°C, which is 1.47°C above the pre‑industrial reference period. A companion summary of Global Climate Highlights emphasizes that 2025 was only marginally cooler than the record years before it, reinforcing a clear long‑term warming trend.
Those numbers are not abstract. A detailed briefing that 2025 was the world’s third‑warmest year, compiled with input from US National Oceanic, notes that all of the 11 warmest years on record have occurred in the recent past. A separate technical release from ECMWF confirms that 2025 was the third‑warmest year on record, with “widespread” warmth across the globe and a global average surface air temperature of 14.97°C that was 1.47°C above the pre‑industrial level.
Scientists call 2025 a “warning shot”
Faced with these figures, many researchers are shifting their language from cautious to blunt. In a widely cited comment, Professor Pierre Friedlings said that “with CO2 emissions still increasing, keeping global warming below 1.5°C is no longer plausible,” arguing that the world now needs to focus on limiting overshoot and bringing temperatures back down later. That assessment is grounded in the same temperature records that show 2025 at 1.47°C above pre‑industrial levels, as well as in measurements of atmospheric CO2 concentrations that continue to rise.
Other experts frame 2025 as a warning rather than a final verdict. A group of Scientists interviewed by NPR describe the latest near‑record year as a “warning shot,” noting that all of the last three years are the hottest in the instrumental record according to the Berkeley Earth monitoring group. A separate summary of the same message from Five science teams underscores that all of the last three years also rank among the top three for ocean heat content, a sign that excess energy is accumulating in the seas as well as the air.
Three hottest years, and what comes next
Looking across the last few years, the pattern is unmistakable. A detailed feature on how Earth experienced its third‑warmest year notes that human‑caused global warming pushed temperatures to near‑record levels despite the cooling influence of La Niña. A separate synthesis of satellite and surface data concludes that 2025 was Earth’s 3rd‑warmest year on record, with Human emissions identified as the primary driver of the long‑term trend.
From a physical‑climate perspective, the last three years have effectively tested the upper limits of what many models projected for the mid‑2020s. A synthesis of recent work on how Although 2025 was slightly cooler than the two previous years, averaging 1.47 degrees above pre‑industrial temperatures, Earth is warming faster than in earlier decades and Arctic sea ice was also at record lows. A follow‑up discussion of the same findings from Earth stresses that these three consecutive record‑setting years have occurred while Antarctic sea ice was also at record lows, a pairing that points to deep structural changes in the climate system.
More from Morning Overview
