The Unrelenting Heat: 2025 Marks Third-Warmest Year on Record Amid La Niña Cooling – A Stark Warning from UN Experts
PAHARI BARUAH
In a sobering confirmation released on January 14, 2026, the World Meteorological Organization (WMO) declared that 2025 ranked as one of the three warmest years in the 176-year instrumental record, extending an alarming 11-year streak of exceptional global temperatures. Despite the presence of La Niña-a natural climate pattern that typically exerts a cooling influence-the planet’s average surface temperature reached 1.44°C (±0.13°C) above the pre-industrial baseline (1850–1900), according to the agency’s consolidated analysis of eight leading international datasets.

Two datasets (including NASA’s GISTEMP and DCENT) placed 2025 as the second-warmest year, while the remaining six-including those from NOAA, Copernicus ERA5, Berkeley Earth, HadCRUT5, JRA-3Q, and China’s CMST-ranked it third, behind 2024 (the hottest on record) and 2023. The differences among rankings are minor and often fall within uncertainty margins, underscoring how tightly clustered the recent extremes have become.
The three-year period from 2023 to 2025 averaged 1.48°C (±0.13°C) above pre-industrial levels-the first such consecutive trio to surpass the symbolic 1.5°C threshold from the Paris Agreement (though the treaty targets long-term averages over decades, not short-term spikes). Copernicus ERA5 data aligned closely, reporting 2025 at 1.47°C above pre-industrial, with the 2023–2025 average exceeding 1.5°C for the first time in any three-year span.
WMO Secretary-General Celeste Saulo emphasized the human fingerprint: “The year 2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally because of the accumulation of heat-trapping greenhouse gases in our atmosphere.” This resilience against natural variability highlights how dominant anthropogenic emissions have become in overriding short-term fluctuations.
Oceans absorbed the brunt of the excess heat-about 90% of it-with upper ocean heat content surging by roughly 23 zettajoules from 2024 to 2025 (equivalent to about 200 times the world’s 2024 electricity generation). Global sea surface temperatures ranked third-highest on record, at 0.49°C above the 1981–2010 baseline despite La Niña’s dampening effect. Regionally, 33% of the ocean surface fell in the top-three warmest conditions since 1958, and 57% in the top five, spanning the tropical and South Atlantic, Mediterranean, North Indian Ocean, and Southern Ocean.
These elevated temperatures amplified extreme weather worldwide in 2025, from record wildfire emissions in Europe to devastating floods in Pakistan (claiming over 1,000 lives) and intensified tropical cyclones like Hurricane Melissa in the Caribbean. NOAA data further noted 101 named storms globally-above the long-term average-with 52 reaching hurricane strength and 24 becoming major systems.
Opinion and Broader Context This data is not merely a statistical milestone; it is a glaring red flag that the window for meaningful climate action is narrowing faster than anticipated. The current long-term warming level hovers around 1.4°C above pre-industrial, and at the present trajectory, the Paris 1.5°C limit could be breached (on a 30-year average) by the end of this decade-over a decade earlier than projections made when the agreement was signed in 2015.

The persistence of record heat even under La Niña conditions debunks any notion that recent extremes were solely “natural.” Fossil fuel combustion, deforestation, and industrial activities continue to load the atmosphere with CO₂ (which surpassed 423 ppm in recent years) and other greenhouse gases at unprecedented rates. Short-term variability like La Niña or the lingering effects of the 2022 Hunga Tonga eruption (which had a minor net cooling then slight warming influence) cannot mask the relentless underlying trend.
The implications are profound: escalating risks to human health (through heatwaves and disease vectors), food security (via disrupted agriculture), biodiversity (with accelerating species loss), and economic stability (from disaster damages and insurance crises). Vulnerable regions-small island states, low-lying deltas, and already-hot tropics-face existential threats.
The full State of the Global Climate 2025 report, due in March 2026, will detail additional indicators like sea-level rise, glacier retreat, and sea ice decline. Until then, the message from 2025 is unequivocal: emissions must fall sharply and immediately. Renewable energy transitions, nature-based solutions, and equitable global cooperation are no longer optional-they are urgent necessities. The planet is not waiting; neither should we.

Headline Image: © WMO/Felipe Molina The thawing of ice is accelerating in Antarctica due to increasing temperatures.
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