Rising CO2 Levels May Affect Blood Chemistry and Human Health, Study Warns

Rising carbon dioxide (CO2) levels in the atmosphere are not only intensifying heatwaves, droughts, wildfires and severe storms but may also be affecting human health, a recent study published in Air Quality, Atmosphere & Health has warned. Researchers from the Australian National University and Curtin University analysed 21 years of data from the US National Health and Nutrition Examination Survey, which collected blood samples from around 7,000 people annually. During the study period, atmospheric CO2 levels increased from about 369 parts per million (ppm) to 420 ppm, while blood bicarbonate levels, a chemical indicator associated with CO2 balance in the body, rose by around 7%.

The findings suggest that the body may be adapting to higher CO2 exposure by increasing bicarbonate levels to help regulate blood acidity. However, prolonged exposure to elevated CO2 has been linked in earlier research to symptoms such as headaches, fatigue, reduced concentration and impaired decision-making, while animal studies have indicated possible effects including inflammation and changes in kidney, heart and bone tissues. The researchers also highlighted potential changes in calcium and phosphorus levels, which could affect normal body functions. Although current levels have not yet resulted in widespread severe symptoms, continued growth in greenhouse gas emissions could push atmospheric CO2 beyond 500 ppm by the middle of the century, potentially creating greater health risks for future generations. The study underscores the need for stronger action to curb greenhouse gas emissions.