Rising atmospheric CO2 linked to measurable changes in human blood chemistry

Scientists from The Kids Research Institute Australia, Curtin University and the Australian National University analyzed more than two decades of U.S. health surveys, reviewing blood samples from roughly 7,000 individuals collected every two years between 1999 and 2020. They documented a steady rise of about 7% in average serum bicarbonate, a marker linked to carbon dioxide, alongside decreasing calcium and phosphorus concentrations.

These biochemical shifts occurred as atmospheric CO₂ increased from roughly 369 ppm in 2000 to above 420 ppm today. Lead author Alexander Larcombe explained that the body retains extra bicarbonate to maintain blood pH as external CO₂ rises, but prolonged adaptation may push bicarbonate toward the top of its normal range within 50 years, with other minerals edging toward lower limits later this century. Co-author Phil Bierwirth stressed the study does not prove direct causation but the consistent pattern across a large population merits attention. They recommend tracking atmospheric composition together with physiological markers, adding a potential long-term public-health dimension to climate policy.