September 2025 ranked as the world's third warmest September on record, with land and sea surface temperatures holding near historic highs, the Copernicus Climate Change Service (C3S) reported.
The C3S data show the global average surface temperature hit 16.11 degrees Celsius (0.27 degrees lower than September 2023 and 0.07 degrees lower than September 2024) yet still a striking 1.47 degrees above pre-industrial levels. This persistent warmth underscores the growing influence of greenhouse gases in our atmosphere.
Sea surface temperatures were equally alarming, averaging 20.72 degrees Celsius in September. Much of the North Pacific recorded temperatures far above the 1991-2020 average, with some areas reaching all-time highs. In contrast, the central and eastern equatorial Pacific stayed near or just below average, signaling a neutral phase of the El Nino-Southern Oscillation.
Polar ice also felt the heat: Arctic sea ice extent was 12 percent below the 1991-2020 average, while Antarctic sea ice was 5 percent below. Samantha Burgess, C3S strategic lead for climate at the European Centre for Medium-Range Weather Forecasts, noted that this September was only about 0.1 degrees Celsius cooler than September 2024, illustrating how little global temperatures have budged over the past year.
In a related analysis, global think tank Ember highlights how the Chinese mainland's green energy sector is powering a historic shift away from coal, marking a crucial breakthrough in the fight against climate change.
Reference(s):
World just experienced its third warmest September on record
cgtn.com
