CO₂ Levels
The concentration of carbon dioxide (CO₂) in Earth’s atmosphere has now reached a staggering new record of 430.2 parts per million (ppm), a level not witnessed on the planet for millions of years, according to the latest data collected in May 2025.
This alarming milestone was confirmed by researchers from the Scripps Institution of Oceanography at the University of California, San Diego, who conducted the measurements at the Mauna Loa Observatory in Hawaii — a globally recognized site for monitoring long-term atmospheric CO₂ levels.
The new reading represents a sharp increase of 3.5 ppm from May 2024, when the concentration stood at 426.7 ppm. Scientists have long warned that this steady and relentless rise in CO₂ is directly linked to the widespread burning of fossil fuels, such as coal, oil, and gas. These emissions continue to accumulate in the atmosphere, driving global warming and fueling an intensifying climate crisis.
According to climate experts at the Scripps Institution, the implications of rising CO₂ levels are profound and far-reaching. Elevated concentrations of this greenhouse gas are exacerbating extreme weather conditions across the globe — contributing to more intense heatwaves, prolonged droughts, heavier rainfall, and devastating floods. These events are not only growing in frequency but also in severity, putting communities, economies, and ecosystems under increasing pressure.
Beyond the atmosphere, rising CO₂ is also altering the chemistry of our oceans. The gas dissolves into seawater, leading to ocean acidification. This process significantly impacts marine life, particularly species such as corals, mollusks, and some plankton, which rely on calcium carbonate to build their skeletons and shells.
As acidification increases, their ability to survive and reproduce is compromised, threatening entire marine food webs and the livelihoods that depend on them.
While the Mauna Loa Observatory offers the most comprehensive long-term record of atmospheric CO₂, it represents a global average rather than local variations. Some monitoring stations in the Southern Hemisphere — where seasonal cycles differ — have yet to register CO₂ levels surpassing 430 ppm.
However, the broader Global Greenhouse Gas Reference Network, which compiles data from sites around the world, continues to serve as an essential tool for tracking emissions trends and guiding international climate policy.
This troubling development comes on the heels of broader discussions on climate action, such as those held at the recent Astana International Forum.
Participants in the forum highlighted the urgent need for accelerated climate mitigation strategies that are equitable and inclusive, recognizing that climate change is a global challenge that affects all nations, but not equally.
As the planet continues to warm and CO₂ levels climb, scientists and policymakers alike stress the critical importance of immediate and sustained action. The latest data reinforces what experts have been saying for years: the window to avoid the worst impacts of climate change is rapidly closing.
