The World Meteorological Organization (WMO) confirms 2025 ranks as one of the three warmest years ever recorded, despite a cooling La Niña influence. This marks the 11th straight year of record-breaking heat, with average surface temperatures hitting 1.44°C above the 1850-1900 baseline.
Consequently, extreme weather like heatwaves and cyclones intensified, highlighting the need for robust early warning systems.
Record-Shattering Temperature Trends
WMO analyzed eight global datasets, including Copernicus ERA5 and NASA GISTEMP, to verify these figures. Two datasets place 2025 as the second-warmest year, while six rank it third, with a three-year average (2023-2025) at 1.48°C above pre-industrial levels. Moreover, the period from 2015-2025 emerges as the hottest decade in 176 years of observations.
Even with La Niña cooling the Pacific, greenhouse gas buildup drove relentless warming. Land and ocean temperatures fueled devastating events worldwide. Thus, WMO stresses authoritative climate data for decision-makers everywhere.
Ocean Heat Hits Historic Highs
Oceans absorbed about 90% of excess global heat, with upper 2000m heat content rising 23 Zettajoules from 2024—equivalent to 200 times humanity’s annual electricity use. A study in Advances in Atmospheric Sciences notes 33% of ocean areas endured their top-three warmest conditions historically. Specifically, the tropical Atlantic, Mediterranean, and North Indian Ocean faced extreme warming.
Sea surface temperatures averaged 0.49°C above the 1981-2010 baseline, ranking third-warmest despite a La Niña dip. This unabated ocean heating signals deepening climate imbalance. As a result, marine ecosystems and weather patterns face growing threats.
Key Climate Facts and Figures
Temperature Anomaly: 1.44°C ± 0.13°C above 1850-1900 average for 2025.
Three-Year Streak: 2023-2025 warmest trio across all datasets.
Ocean Surge: 23 Zettajoules added, vast energy equivalent.
Regional Hotspots: 57% of oceans in top-five warmest states.
Have you felt the impact of these record heats in your region? What steps can communities take next?
Q&A: Decoding the WMO Report
Q: Why was 2025 so hot despite La Niña?
A: Accumulated greenhouse gases overwhelmed the cooling effect, pushing temperatures to record levels.
Q: How do datasets confirm these rankings?
A: Eight sources, from NOAA to new additions like CMST, align on top-three status for 2025, using stations, ships, and reanalysis models.
Q: What makes ocean heat a key indicator?
A: It stores 90% of excess warming, with massive Zettajoule gains showing irreversible trends.
Q: How does this affect extreme weather?
A: Higher land/ocean temps supercharged heatwaves, floods, and cyclones globally.
FAQ: Climate Action Essentials
What datasets back WMO’s 2025 findings?
ERA5, JRA-3Q, NASA GISTEMP, NOAA, HadCRUT, Berkeley Earth, plus new DCENT and CMST for comprehensive analysis.
Is 2025 the absolute hottest year?
No, but second or third in rankings; past 11 years dominate records.
Why focus on ocean heat content?
OHC tracks long-term warming reliably, with 2025’s 23 ZJ rise dwarfing human energy output.
What role do early warnings play?
They mitigate risks from intensified cyclones and rains, as Secretary-General Celeste Saulo emphasizes.
Can La Niña reverse these trends?
Temporarily cools but cannot offset greenhouse-driven heat buildup.
Urgent cuts in emissions, alongside global monitoring, offer hope amid escalating records. Nations must act swiftly to safeguard oceans and weather stability for future generations.
