Carbon dioxide (CO₂) levels in Earth’s atmosphere have reached an unprecedented 430.2 parts per million (ppm), the highest in millions of years, according to new research from the Scripps Institution of Oceanography at the University of California, San Diego.
This milestone was recorded at NOAA’s Mauna Loa Observatory in Hawaii — a leading global site for measuring CO₂ trends — showing a year-on-year increase of 3.5 ppm from May 2024. Scientists attribute this alarming rise to continued global dependence on fossil fuels, pushing the world further off track from its climate goals.
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“This amount of atmospheric carbon dioxide hasn’t been seen for at least three to five million years,” a Scripps representative warned, highlighting the severity of the situation. Experts say the accelerating CO₂ concentration is already intensifying extreme weather conditions worldwide — from deadly heatwaves and long-term droughts to flooding and heavy rainfall.
Beyond the atmosphere, the oceans are also suffering. Increased CO₂ absorption is causing ocean acidification, which weakens the ability of marine species like corals and shellfish to maintain their protective structures, threatening entire marine ecosystems.
Although Mauna Loa provides the most reliable long-term data on CO₂, the numbers can vary regionally. Southern Hemisphere monitoring stations, for example, have not yet crossed the 430 ppm threshold due to seasonal differences. Still, data from a wide network of international stations feed into the Global Greenhouse Gas Reference Network, which supports climate policy and scientific research worldwide.
These alarming figures have intensified calls for swift and fair climate action. At the Astana International Forum, global climate leaders emphasized the importance of inclusive strategies that address both rich and poor nations. Despite the growing body of scientific evidence, emissions are still rising globally.
“This is no longer a distant threat — it’s a crisis unfolding in real-time,” said a forum speaker. “We have solutions, but lack the collective urgency to act.”
The findings arrive as various regions — notably South Asia and sub-Saharan Africa — experience unpredictable weather and rising food insecurity, worsened by climate change. With COP30 approaching, researchers hope the record-breaking CO₂ levels will push governments and citizens to take meaningful action.
