WMO Greenhouse Gas Bulletin 2025: Record CO2, Methane, Nitrous Oxide and the Rise of SF6

At a press briefing in Geneva, the World Meteorological Organization presented its annual Greenhouse Gas Bulletin 2025, showing that concentrations of long-lived greenhouse gases in the atmosphere have reached new records. Deputy Secretary-General Claire Barret and Senior Scientific Officer Oxana Tarasova walk through the measured data and answer journalists' questions on what drives the numbers and what they imply for climate action.

■ Record concentrations of the three main gases
- CO2, methane and nitrous oxide all hit new highs in 2025, with levels far above pre-industrial times
- Comparison with the bulletin's first edition in 2004 and the growth rates relative to the 10-year average
- Roughly half of annual CO2 emissions remain in the atmosphere, with the rest absorbed by land and oceans

■ The role of El Niño
- Why strong El Niño years typically produce surges in CO2 growth through drought, stressed vegetation and biomass burning
- Why the 2025 growth rate was notable despite being a La Niña year, and what the current strong El Niño may mean for the coming year

■ A focus on sulfur hexafluoride (SF6)
- Its link to electricity production and distribution, its extremely long atmospheric lifetime and its very high warming potential
- Why the energy transition needs to be managed with environmental observations in mind

■ Radiative forcing and the data behind the findings
- Carbon dioxide's share of warming since pre-industrial times and since 1990
- The observation network of monitoring stations supporting the measurements, and the development of a higher-resolution global greenhouse gas watch
- Media questions on public skepticism, upcoming climate reporting and the relevance for negotiators

The briefing offers primary-source access to an official UN agency press conference with slides, expert explanations and unedited Q&A, covering the science, the measurement basis and the policy context. It is suited to journalists, students, policy professionals and anyone seeking a clear, data-based picture of where greenhouse gas concentrations stand and how they are tracked. Viewers come away with an understanding of concentration versus emissions data, the natural factors that modulate the trend, and the range of gases beyond carbon dioxide that shape the atmosphere's trajectory.