Scientists have confirmed 2025 as either the second or third hottest year ever recorded, continuing a relentless warming streak that’s reshaping our planet. Here’s what the latest climate data reveals about this scorching year.
2025 tied with 2023 for second place.
The year is virtually certain to finish as the second or third warmest since record-keeping began around 1850, with global temperatures sitting at 1.48 °C above pre-industrial levels. That’s identical to 2023’s reading and only slightly cooler than 2024, which holds the current record. Europe’s Copernicus Climate Change Service confirmed the rankings using data through November, and there’s basically no chance the final month will change the outcome.
The last 11 years are the 11 hottest on record.
Every single year from 2015 to 2025 has individually ranked as one of the eleven warmest years in 176 years of temperature monitoring. It’s a staggering streak that shows how quickly warming has accelerated, with no cooler years interrupting the pattern. The top three positions all belong to 2023, 2024 and 2025, making the past three years the hottest trio ever documented.
The three-year average broke through 1.5 °C for the first time.
When you average temperatures across 2023, 2024 and 2025, the result exceeds 1.5 °C above pre-industrial levels for the first time in the instrumental record. This is significant because the Paris Agreement set 1.5 °C as the critical threshold to avoid catastrophic climate impacts, though one year or even three years above that mark doesn’t technically breach the agreement, which refers to long-term warming averaged over 20 years. Still, it’s not a good sign.
@apnews Climate change worsened by human behavior made 2025 one of the hottest years ever recorded. Also, the three-year warming average has crossed the threshold of 1.5 degrees Celsius (2.7 Fahrenheit) since pre-industrial times set in the 2015 Paris Agreement for the first time. #climatechange #climate ♬ original sound – The Associated Press
This happened during a La Niña year.
What makes 2025’s heat particularly worrying is that it occurred despite La Niña conditions, which typically cool Pacific Ocean waters and lead to slightly lower global temperatures. The La Niña was weak and short-lived, but its presence should have dampened global heat. Instead, 2025’s temperatures eclipsed many past El Niño years, which bring warming effects. Compared to the record-setting 2016 El Niño year, 2025 looks decidedly hotter.
Arctic sea ice hit record lows.
Arctic sea ice extent reached its annual maximum of 13.8 million square kilometres in March 2025, the lowest maximum extent in the satellite record. The winter freeze simply didn’t produce as much ice as any year before. Antarctic sea ice also tracked well below average throughout the year, finishing third lowest on record for both its annual minimum and maximum extents.
CO2 concentrations reached unprecedented levels.
Atmospheric carbon dioxide hit 423.9 parts per million in 2024, a 53% increase from the pre-industrial level of 278 ppm back in 1750. The jump from 2023 to 2024 was 3.5 ppm, the largest single-year increase in recent observational history. These record greenhouse gas levels lock in more heat for the future, guaranteeing continued warming even if emissions stopped tomorrow.
Extreme weather events killed thousands.
Scientists identified 157 extreme weather events in 2025 that met criteria for being most severe, meaning they caused over 100 deaths, affected more than half an area’s population or triggered states of emergency. Heat waves proved the deadliest overall, whilst tropical cyclones in Southeast Asia killed over 1,800 people in November alone. Europe’s summer heat wave killed 3,317 people, and monsoon flooding in South Asia claimed over 2,200 lives.
Heat waves are now 10 times more likely.
Climate change has made some of 2025’s heat waves 10 times more likely compared to just a decade ago, according to World Weather Attribution researchers. These heat events would have been almost impossible without human-induced warming. The frequency increase means what used to be rare extremes are now regular occurrences that happen multiple times per decade rather than once in a century.
Glaciers lost the most ice ever recorded.
The 2023-2024 hydrological year marked the third consecutive year that all monitored glaciated regions worldwide recorded net mass loss. Reference glaciers tracked by the World Glacier Monitoring Service showed a global annual mass balance of negative 1.3 metres of water equivalent, or 450 gigatonnes. That’s equal to 1.2 millimetres of global mean sea-level rise and represents the largest ice loss on record, stretching back to 1950.
@bbcnews 2025 is on course to be the UK's hottest year since records began, with climate change continuing to drive higher temperatures. #Weather #Heatwave #Climate #ClimateChange #UKWeather #BBCNews ♬ original sound – BBC News
Ocean temperatures stayed dangerously high.
Sea surface temperatures remained well above average throughout 2025, with the North Pacific experiencing much above-average readings and record highs in western areas. The Norwegian Sea saw record-breaking temperatures, as did the Coral Sea off Australia’s eastern coast. Ocean heat content, which reached record levels in 2024, continued rising in 2025, storing enormous amounts of thermal energy that will take decades to dissipate.
Energy demand surged 4% above normal.
The record heat of 2024 pushed global energy demand 4% above the 1991-2020 baseline, and 2025 continued that trend. People needed more electricity for air conditioning and cooling systems, straining power grids worldwide. This creates a feedback loop where warming drives energy use, which often means burning more fossil fuels, which accelerates warming further.
Early warning systems expanded, but there are still gaps.
Countries with multi-hazard early warning systems more than doubled from 56 to 119 since 2015, representing significant progress in climate preparedness. Least developed countries and small island states showed a 5% increase in access over just the past year. However, 40% of the world’s countries still lack these crucial systems, leaving billions of people vulnerable to extreme weather without adequate advance notice.
It’s virtually impossible to limit warming to 1.5 °C now.
Climate scientists have stated it will be virtually impossible to keep global warming below 1.5 °C in the next few years, given current trends and record greenhouse gas levels. The World Meteorological Organization confirmed this grim outlook, noting that concentrations of heat-trapping gases continue rising while ocean heat content reached record levels. The Paris Agreement target is slipping further from reach with each passing year.