Earth Sets Another Heat Record Despite La Niña’s Cooling Effect/ Newslooks/ WASHINGTON/ J. Mansour/ Morning Edition/ Despite the cooling effects of La Niña and a frigid U.S. winter, Earth experienced its hottest January on record, according to the European climate agency Copernicus. A new study from former NASA scientist James Hansen suggests global warming is accelerating, sparking debate among experts. Scientists attribute the record heat to greenhouse gas emissions and persistently warm ocean temperatures.
Earth’s Heat Record: Quick Look
- January 2025 was the hottest ever recorded, surpassing the previous record set in January 2024.
- Global temperatures were 1.75°C (3.15°F) above pre-industrial levels.
- La Niña’s cooling effect failed to counteract the overall warming trend.
- Ocean temperatures remain at record highs, contributing significantly to global heat.
- U.S. winter was cold, but much of the planet experienced extreme warmth.
- Arctic regions saw temperatures 30°C (54°F) above normal, causing ice melt.
- Climate experts debate whether global warming is accelerating, with some citing recent data as evidence.
Earth’s January Heat Record Defies Expectations
Despite La Niña’s expected cooling effects and a frigid winter across the U.S., Earth experienced its hottest January on record in 2025, according to Copernicus, the European climate monitoring agency. The shocking finding has intensified the debate among climate scientists about whether global warming is accelerating beyond previous expectations.
Breaking Heat Records Yet Again
January 2025 was 0.09°C (0.16°F) warmer than January 2024, the previous record-holder, and 1.75°C (3.15°F) above pre-industrial levels, according to Copernicus data. This marks the 18th month out of the last 19 that global temperatures have hit or exceeded the internationally recognized warming threshold of 1.5°C above pre-industrial times. While scientists don’t consider this limit officially “breached” until sustained for 20 years, the pattern is concerning.
Climate records from Copernicus date back to 1940, while other agencies such as NASA and the UK Met Office extend their records to 1850. However, climate proxies like tree rings and ice cores suggest that today’s temperatures are the highest in 120,000 years—essentially since the dawn of human civilization.
Why Is It Still So Hot?
The primary driver of these rising temperatures remains greenhouse gas emissions from burning fossil fuels. However, natural climate variations, such as El Niño and La Niña, typically influence global temperatures as well.
- El Niño, a warming phase in the Pacific Ocean, contributed to record heat in 2023.
- La Niña, its cooler counterpart, began developing in January 2025 and was expected to moderate temperatures.
- Instead of cooling, the planet remained at record-high temperatures, defying predictions.
Samantha Burgess, a climate expert with Copernicus, noted that ocean temperatures remained abnormally high even with La Niña in effect, which could explain the continued heat.
A Freezing U.S., But a Scorching Arctic
While much of the U.S. shivered through a colder-than-usual winter, vast areas of the planet were experiencing extreme warmth. The Arctic saw particularly shocking temperature anomalies, with some areas of Canada experiencing temperatures 30°C (54°F) above average. This warmth led to early ice melt, raising concerns about long-term ice loss.
Copernicus reported that Arctic sea ice levels for January tied the record for the lowest ever, while the U.S.-based National Snow and Ice Data Center ranked it the second-lowest after 2018.
Will 2025 Be Another Record-Breaking Year?
Former NASA scientist James Hansen, a key figure in climate science, believes that global warming is accelerating. In a newly published study, Hansen and colleagues argue that since 2010, global temperatures have been rising twice as fast as they did in the previous four decades.
Hansen suggests that the recent reduction in sulfur pollution—due to stricter shipping regulations—could be contributing to additional warming. Sulfur aerosols previously helped reflect sunlight, slightly offsetting greenhouse gas-induced warming. With less of these pollutants, temperatures could be rising even faster.
Despite some experts predicting that 2025 might be cooler than recent years, Hansen warns that it could still challenge 2024’s record for hottest year ever.
A Divided Climate Science Community
Not all climate experts agree with Hansen’s acceleration theory.
- Gabe Vecchi (Princeton University) argues there isn’t enough data yet to confirm that recent warming is beyond natural variability.
- Michael Mann (University of Pennsylvania) believes that the observed warming aligns with previous climate model projections, rather than indicating an unexpected acceleration.
However, other scientists, like Jonathan Overpeck from the University of Michigan, see the persistence of record-breaking warmth as clear evidence that climate change is intensifying.
The Bottom Line
Even with La Niña, which typically cools global temperatures, January 2025 broke heat records. The Arctic continues to warm at an alarming rate, and experts remain divided on whether climate change is accelerating beyond predictions. As the debate continues, one thing is certain: Earth’s temperatures show no signs of cooling anytime soon.
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