Human Blood Chemistry Tracks Rising Atmospheric CO2

Rising levels of carbon dioxide in the atmosphere may already be influencing human biology. New research has identified long-term changes in blood chemistry that appear to track rising atmospheric CO2, raising concerns that an important blood marker could approach the upper end of its healthy range within the next several decades.

The study, led by Associate Professor Alexander Larcombe from The Kids Research Institute Australia, examined over 20 years of U.S. population health data, analyzing blood test results from roughly 7,000 people at two-year intervals between 1999 and 2020.

The researchers found persistent changes in several measures of blood chemistry that closely followed the upward trend in atmospheric CO2. Since 1999, average serum bicarbonate levels have increased by about 7 percent. Bicarbonate is a blood marker closely associated with carbon dioxide in the body. During the same period, average levels of calcium and phosphorus decreased.

Bicarbonate is essential for regulating the body’s acid-base balance. As CO2 increases, the body can retain additional bicarbonate to help keep blood pH stable. Although this response helps preserve that balance, maintaining it over long periods could have physiological effects.