The concentration of carbon dioxide (CO₂) in the Earth’s atmosphere has surged to 430.2 parts per million (ppm) — the highest level recorded in millions of years — according to new data released by researchers at the Scripps Institution of Oceanography, University of California, San Diego.
The measurement was taken at the National Oceanic and Atmospheric Administration (NOAA)’s Mauna Loa Observatory in Hawaii, a globally recognised benchmark for tracking atmospheric CO₂. The new figure reflects an increase of 3.5 ppm over the past year, rising from 426.7 ppm in May 2024.
Climate scientists have long warned that continued reliance on fossil fuels is the primary driver behind the increase in greenhouse gas emissions. The latest reading, they say, is further evidence that the world is veering off course from its climate commitments.
“Humanity has not witnessed this level of carbon dioxide in the atmosphere in at least three to five million years,” said a spokesperson from the Scripps Institution. “We are entering uncharted territory.”
Researchers warn that the rapidly rising concentration of CO₂ is already fuelling more extreme weather events across the globe. From scorching heatwaves and protracted droughts to torrential rainfall and widespread flooding, the effects are becoming more frequent and more severe.
In addition to climate disruptions on land, rising CO₂ levels are contributing to ocean acidification — a lesser-known but equally grave consequence of greenhouse gas buildup. Acidification impairs the ability of marine organisms such as corals, shellfish, and plankton to form their protective shells and skeletons, placing entire ecosystems at risk.
Although the Mauna Loa Observatory offers the most consistent long-term data on global atmospheric CO₂, it does not account for regional variations. In the Southern Hemisphere, for instance, where seasonal cycles operate inversely to those in the North, some monitoring stations have yet to cross the 430 ppm threshold.
However, data collected from monitoring sites across continents feeds into the Global Greenhouse Gas Reference Network, an international resource that informs both scientific assessments and climate policy.
The implications of the latest data have renewed calls for urgent and equitable climate action. At a recent panel session during the Astana International Forum, policymakers and climate experts discussed ways to accelerate global efforts to reduce emissions, emphasising the need for inclusive strategies that serve both developed and developing nations.
Despite years of warnings and mounting evidence, global emissions have continued to rise. Experts say that unless immediate steps are taken to curtail fossil fuel use and transition to cleaner energy sources, the planet is on track for further instability.
“This is not a future problem — it is already affecting lives and livelihoods around the world,” said one panellist during the forum. “We have the tools, but we lack the urgency.”
The findings come at a time when several regions, including parts of South Asia and sub-Saharan Africa, are grappling with erratic weather patterns and rising food insecurity — conditions exacerbated by the changing climate.
As world leaders prepare for the upcoming COP30 summit, scientists hope the latest figures will serve as a wake-up call to policymakers and the public alike.
