A population study suggests the human body may already be responding to changes in the composition of the atmosphere, with the air outside leaving a subtle signature in human blood.
Researchers from the Kids Research Institute, Australia, Curtin University, and the Australian National University (ANU) in the study identified gradual changes in a key carbon dioxide-related blood marker, warning that it could approach the upper limit of its healthy range within decades if the trends persist.
Children and adolescents are especially tipped to be most affected because their developing bodies could face the longest cumulative exposure to rising atmospheric CO₂.
The researchers analysed more than 20 years of US population data for the study published in Air Quality, Atmosphere and Health, disclosing that several measures of blood chemistry shifted over time in patterns that closely followed increasing atmospheric CO₂.
Using the US National Health and Nutrition Examination Survey (NHANES), the researchers examined blood test results from approximately 7,000 people every two years between 1999 and 2020.
Blood chemistry tracks atmospheric CO₂ Since 1999, average serum bicarbonate levels have increased by about seven percent. Serum bicarbonate is closely connected to the amount of carbon dioxide carried in the body.
During the same period, average concentrations of calcium and phosphorus declined. Those changes occurred as atmospheric CO₂ climbed from approximately 369 parts per million (ppm) in 2000 to more than 420 ppm today.
An author of the study, Associate Professor Alexander Larcombe said the pattern may indicate that the body is already responding to the changing composition of the atmosphere. “What we’re seeing is a gradual shift in blood chemistry that mirrors the rise in atmospheric carbon dioxide, which is driving climate change,” Larcombe said.
The body may be compensating Bicarbonate helps the body maintain its acid and base balance. As CO₂ rises, the body can retain more bicarbonate to keep blood pH stable, but maintaining that adjustment over long periods could have physiological effects.
