Researchers Warn Rising CO2 May Already Be Changing Human Blood Chemistry

A population study suggests the human body may already be responding to changes in the composition of the atmosphere. The air outside may be leaving a subtle signature in human blood. Researchers have identified gradual changes in a key carbon dioxide-related blood marker and warn that it could approach the upper limit of its healthy [...]

A population study suggests the human body may already be responding to changes in the composition of the atmosphere. The air outside may be leaving a subtle signature in human blood. Researchers have identified gradual changes in a key carbon dioxide-related blood marker and warn that it could approach the upper limit of its healthy range within decades if current trends persist.

Children and adolescents may be especially relevant because their developing bodies could face the longest cumulative exposure to rising atmospheric CO2. Researchers from The Kids Research Institute Australia, Curtin University, and The Australian National University (ANU) analyzed more than 20 years of U.S. population data for a study published in Air Quality, Atmosphere and Health. They found that several measures of blood chemistry shifted over time in patterns that closely followed increasing atmospheric CO2.

Using the U.S. 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. Associate Professor Alexander Larcombe, an