World just experienced its third warmest September on record

The world has just experienced its third warmest September on record, with land and sea surface temperatures remaining persistently high, the EU's climate monitoring network reported on Thursday.

The Copernicus Climate Change Service (C3S) said that the global average surface temperature in September this year was 16.11 degrees Celsius, down by 0.27 degrees and 0.07 degrees from the same month in 2023 and 2024, respectively, but still 1.47 degrees above pre-industrial level.

According to the C3S, the global average sea surface temperature in September was 20.72 degrees Celsius. Sea surface temperatures in most of the North Pacific remained significantly above the long-term average, reaching historical highs in some areas.

In contrast, sea surface temperatures in the central and eastern equatorial Pacific were near or below the 1991-2020 average, indicating a neutral phase of the El Nino-Southern Oscillation.

In addition, the monthly sea ice extent in the Arctic was 12 percent below the long-term average for the period, while the monthly sea ice extent in the Antarctic was 5 percent below the long-term average.

Samantha Burgess, strategic lead for climate in the C3S at the European Centre for Medium-Range Weather Forecasts, said that September 2025 ranked only less than 0.1 degrees Celsius cooler than September 2024.

"A year on, the global temperature context remains much the same, with persistently high land and sea surface temperatures reflecting the continuing influence of greenhouse gas accumulation in the atmosphere," she said.

This week also saw a new analysis from global think tank Ember underscoring how China's green energy sector is powering the world's break from coal, a crucial step for climate action.