GabyAccording to experts from the Scripps Institution of Oceanography in San Diego, California, the average monthly level of CO2 has surpassed 430 parts per million (ppm) for the first time. The average reading for May 2025 reached 430.2 ppm, marking the highest level since precise measurements began 67 years ago. Why should this concern humanity? The more CO2 in the atmosphere, the faster global warming accelerates, potentially making the Earth’s surface too hot for human life. Significant concentrations of carbon dioxide also lead to numerous health issues, including cognitive impairments, drowsiness, nausea, and in extreme cases, even death. “Another year, another record. And it’s sad,” said Ralph Keeling, director of the Scripps CO2 program, which studies issues related to carbon dioxide. He added that CO2 levels in the Northern Hemisphere peak in May.
Like other greenhouse gases, carbon dioxide acts like a blanket, trapping heat and warming the lower layers of the atmosphere, as reported by the Daily Mail. This alters weather patterns and leads to extreme phenomena such as heatwaves, droughts, wildfires, heavy rainfall, and floods. The rise in CO2 levels also contributes to ocean acidification, making it harder for marine organisms like crustaceans and corals to form solid skeletons and shells.
Alarming Figures
New shocking measurements were obtained by experts at the Mauna Loa Observatory, a research station located on the slopes of the Mauna Loa volcano in Hawaii, at an elevation of about 11,000 feet (3,400 meters). According to researchers, the average monthly value for May 2025 at the observatory—430.2 ppm—is 3.5 ppm higher than the May 2024 figure. CO2 is the most prevalent greenhouse gas produced by human activities, and it can remain in the atmosphere and oceans for thousands of years. Scientists believe that the current concentration of carbon dioxide in the Earth’s atmosphere is equivalent to levels observed 4.1 to 4.5 million years ago, during a period known as the “Pliocene climatic optimum.” At that time, sea levels were 24 meters higher than they are today, and the average global temperature was 3.9 °C higher than pre-industrial levels. In fact, the climate during that period was so warm that vast forests covered areas of the Arctic that are now barren, cold tundra.
Researchers clarified that the new measurements from the Mauna Loa Observatory reflect the average state of CO2 in the atmosphere of the Northern Hemisphere. Meanwhile, in the Southern Hemisphere, CO2 concentrations have yet to exceed the 430 ppm mark. Interestingly, the first person to understand that CO2 levels in the Northern Hemisphere peak in May was Ralph Keeling’s father, Charles David Keeling, who was also a climate researcher at the Scripps Institution of Oceanography. In 1958, he began tracking CO2 concentrations at the Mauna Loa Observatory and documented the long-term increase now known as the Keeling Curve.
