How do regional hottest-year records compare to the global top 10?
Executive summary
Global datasets agree that the past three years are the hottest on record—2024, 2023 and 2025—placing 2025 typically as the third-warmest year globally, with small differences among analyses (Copernicus puts 2025 0.01°C cooler than 2023 and 0.13°C cooler than 2024) [1], and climate agencies warn that similar near-record warmth will persist into 2026 [2]. Regionally, however, the story is louder and more uneven: many ocean basins and land regions registered top-three or record-warm conditions in 2025 even though the year ranked third globally, showing that local and regional records often diverge from the global top-10 list in both magnitude and timing [3] [4].
1. Global top-10 context: the recent acceleration in record years
Multiple monitoring groups—including Copernicus, NOAA and Berkeley Earth—report that 2025 joined 2024 and 2023 as the three warmest years on record, cementing an accelerating trend in global mean surface temperature and making near-record years the new normal according to the WMO and national agencies [1] [5] [6]. Long-term analyses and projections say it will be common for years in the current decade to rank inside the global top 10 unless an abrupt natural cooling event occurs, reflecting both steadily rising greenhouse gases and superimposed natural variability such as El Niño/La Niña [7] [2].
2. Regional heat: hotspots can beat the global ranking by wide margins
Regional metrics show sharper extremes than the global ranking suggests: Copernicus reported Antarctica’s warmest year on record and among the warmest Arctic seasons—surface air temperatures in the Arctic for Oct 2024–Sep 2025 were the warmest since 1900 in some seasons—while Berkeley Earth estimated that 8.5% of the global population experienced record-high annual average temperatures in 2025 [8] [9] [4]. In other words, a year that is “third warmest globally” can contain many local records and entire regions enduring their hottest conditions ever recorded [4] [8].
3. Oceans and polar amplification: different basins, different records
Ocean heat content and regional sea-surface patterns magnify local departures from the global mean: ocean heat content in the upper 2,000 m set another record for the ninth consecutive year in 2025, and roughly one-third of the global ocean area ranked among its historical top-three warmest conditions for 1958–2025, with about 57% in the top five—underscoring basin-scale warming even within a global top-three year [9] [3]. Polar regions have warmed faster than the global average, so Antarctica and parts of the Arctic can set local records while tropical regions vary with ENSO and other modes [1] [3].
4. Why regional records don’t map one-to-one with global top-10 ranks
Regional records diverge from global rankings for three reasons reported across monitoring agencies: first, the global mean averages large spatial contrasts, muting extremes that are intense locally [1]; second, natural variability (El Niño/La Niña, volcanic aerosols) modulates regional patterns differently from year to year—Carbon Brief notes volcanic aerosol effects and changing ENSO likelihood for 2026 [2]; third, datasets and definitions differ (land-only vs. ocean-including, reanalysis vs. station-based), so a region may register a local record in one product even if the global average slots the year at #3 in another [1] [10].
5. Consequences and outlook: many local records foreshadow higher global ranks ahead
Because region-scale extremes—polar warmth, ocean heat uptake and pervasive top-three ocean areas—are persistent and intensifying, scientists warn that an El Niño could push future years above current records and that the 1.5°C threshold is being approached more quickly than expected, increasing the chance of years breaking into the global top two or one in coming years [6] [4] [2]. Monitoring groups caution that the past 11 years are the warmest 11 on record and that continued greenhouse‑gas emissions make it likely that many regions will keep setting local records even if the global rank fluctuates modestly [1] [11].