U.N. Report Finds Greenhouse Gases Hit Record Levels Again In 2025

The World Meteorological Organization said greenhouse gas concentrations hit record highs again in 2025, releasing its 22nd Greenhouse Gas Bulletin on Tuesday, October 27, 2026, and warning levels will likely rise further.^[1]

Global average carbon dioxide reached 426.8 parts per million in 2025, methane 1,948 parts per billion, and nitrous oxide 339.1 parts per billion. Those 2025 levels correspond to about 153 percent, 267 percent and 126 percent of pre-industrial concentrations, respectively. Carbon dioxide rose by 2.8 ppm from 2024 to 2025, compared with a record 3.6 ppm jump from 2023 to 2024 and a decade average rise of 2.6 ppm.^[1]

The bulletin also flagged steady three-decade growth in sulfur hexafluoride and a recent rise in atmospheric hydrogen linked to energy systems.^[1] WMO officials warned concentrations will likely climb again in 2026 because of continued fossil fuel use and a developing El Nino that weakens land carbon sinks.^[1]

In 2024, carbon dioxide jumped by a record 3.6 ppm, a surge scientists tied to strong emissions and reduced land carbon uptake, and 2025 sustained that elevated trajectory. Rising concentrations make limiting future warming harder because each additional molecule of greenhouse gas adds to cumulative atmospheric heating.

1. CBS News