Greenhouse gas levels hit new records in 2025, with a powerful El Niño expected to worsen the situation by 2027.
Greenhouse gases reach record levels
The World Meteorological Organization (WMO) reported that greenhouse gas concentrations in 2025 reached levels never before recorded. These gases, primarily carbon dioxide, methane, and nitrous oxide, are linked to human activities and contribute to global warming. El Niño returns with increased intensity
El Niño, a natural climate phenomenon marked by warmer-than-average surface temperatures in the equatorial Pacific, has returned and is expected to persist until February 2027. Scientists predict this episode will be more intense than any in the past 1,000 years. El Niño could worsen greenhouse gas surge
The WMO warns that the strengthening of El Niño by the end of 2026 could lead to a new surge in greenhouse gas concentrations. This is because El Niño may reduce the ability of natural carbon sinks—like forests and oceans—to absorb emissions, allowing more CO2 to remain in the atmosphere. Record concentrations of key gases
In 2025, the average concentration of carbon dioxide reached 426.8 parts per million, a significant jump from 377.5 ppm in 2004. Methane and nitrous oxide also reached record levels, with concentrations 167% and 26% higher than pre-industrial times, respectively. WMO warns of extreme weather risks
Ko Barrett, deputy secretary-general of the WMO, emphasized that rising greenhouse gas levels are trapping more heat in the atmosphere, increasing the risk of extreme weather events. These events could have serious impacts on economies and societies, especially as the El Niño phenomenon intensifies. El Niño’s indirect impact on France
While El Niño is unlikely to directly affect weather in France, it may increase the risk of heatwaves and unusually warm conditions in the region. Globally, the phenomenon is expected to cause extreme weather, including droughts and floods, in tropical areas. WMO urges preparation for unprecedented El Niño
The WMO has issued repeated warnings about the potential scale of this El Niño event, noting that it could surpass the limits of historical climate data. Officials are urging governments to take preventive measures to protect vulnerable populations from its effects. COP31 to address climate challenges
The WMO’s report was released just before the upcoming COP31 climate conference in Antalya, Turkey. The event aims to translate global climate commitments into concrete actions, using the latest scientific data to guide negotiations. Public engagement on El Niño
To help the public understand the phenomenon, the website Numerama plans to host an expert Q&A session with Éric Guilyardi, a climatologist at CNRS. Readers will be able to submit questions about El Niño and its effects, with answers provided in a detailed FAQ.
