2025 Ranks as Third-Hottest Year on Record Despite Natural Cooling

Scientists have confirmed that 2025 was the third-hottest year ever recorded globally, trailing only 2024 and 2023, according to analyses released by multiple climate agencies. The result is striking because the year coincided with La Niña conditions in the Pacific Ocean, a natural cooling phase that usually lowers global temperatures. La Niña occurs when surface waters in the central and eastern Pacific become cooler than average, altering global wind and rainfall patterns and typically suppressing global temperatures. Its opposite phase, El Niño, involves unusually warm Pacific waters and usually pushes global temperatures higher.

That 2025 still ranked among the warmest years on record despite La Niña’s cooling influence indicates that human-driven global warming is now overpowering natural climate variability, scientists say. “Human-caused warming is now really overwhelming inter-annual natural variability,” said Daniel Swain, a climate scientist at the University of California. Multiple Agencies, Same Signal Temperature assessments by the EU’s Copernicus Climate Change Service, the UK Met Office, and Berkeley Earth found that 2025 was 1.41°C to 1.47°C warmer than the 1850–1900 average, the period used as a pre-industrial baseline.

NASA data placed 2025 statistically close to 2023, while the US National Oceanic and Atmospheric Administration found it marginally cooler. NOAA, however, reported record-high heat in the upper ocean, an important indicator because oceans absorb most of the excess heat trapped by greenhouse gases. The broader trend is unambiguous. The past 11 years are the 11 hottest on record, and the 25 warmest years have all occurred since 1998.

Natural Cycles Losing Influence

Year-to-year temperature rankings are typically shaped by the El Niño–La Niña cycle, which redistributes heat between the ocean and atmosphere. Historically, the warmest global years almost always coincided with El Niño events, while La Niña years offered temporary cooling.

What distinguishes 2025 is that it was hotter than every El Niño year prior to 2023, despite lacking El Niño conditions. Scientists say this suggests that the planet’s baseline temperature has risen so much that natural cooling phases can no longer offset it. Signs of Faster Warming

Researchers say the intense heat observed from 2023 to 2025 may point to an acceleration in warming. Likely contributors include declines in low-level reflective clouds and reductions in sulfur pollution from shipping, which previously had a modest cooling effect by reflecting sunlight.

Combined with steadily rising greenhouse gas emissions, these changes are allowing more heat to accumulate in the climate system. Crossing the 1.5°C Mark, According to Copernicus, the three-year global temperature average has now exceeded 1.5°C above pre-industrial levels for the first time. This threshold is referenced in the 2015 Paris Agreement as a target to limit climate risks.

Scientists stress that crossing it does not trigger an abrupt shift in climate impacts, but it does signal that the world is approaching sustained warming levels earlier than expected. Copernicus estimates that a long-term breach could occur by 2029, more than a decade sooner than anticipated when the agreement was signed.

Heat, Ice Loss, and Extremes At least half of the world’s land area experienced an above-average number of heat-stress days in 2025. Greenland saw temperature anomalies exceeding 12°C above normal in some regions, with ice melting far faster than usual. February set a record low for global sea ice extent, and Antarctica recorded its hottest year on record.

While total global rainfall was near average, warmer air and oceans intensified floods, wildfires, and tropical storms across several regions. Climate attribution studies increasingly show that global warming makes such extreme events more likely and more severe.

Emissions Still Rising

Scientists emphasise that the primary driver of warming remains the burning of fossil fuels. Despite rapid growth in renewable energy, global greenhouse gas emissions are at an all-time high. Berkeley Earth expects 2026 to rank among the five warmest years on record, as La Niña conditions fade toward a neutral phase. “We still have the ability to manage this,” Swain said, “but we are not managing it.”