Scientists detect a surprising shift in human blood as CO2 rises

Scientists detect a surprising shift in human blood as atmospheric CO2 rises Date: August 15, 2026 Source: The Kids Research Institute Australia Summary: Rising carbon dioxide in the atmosphere may be leaving a measurable imprint inside the human body. Researchers analyzing more than two decades of U. S. health data found that blood bicarbonate levels have climbed about 7% since 1999, while calcium and phosphorus have declined—changes that closely track increasing atmospheric CO2. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Rising atmospheric CO2 may already be quietly altering human blood chemistry, with one key marker potentially nearing its healthy limit within decades. Credit: Shutterstock 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 findings may be particularly important for children and teenagers. Because their bodies are still developing, younger generations are expected to experience the greatest lifetime exposure to elevated atmospheric CO2. Decades of Blood Data Reveal a Shift In a study published in Air Quality, Atmosphere and Health, scientists from The Kids Research Institute Australia, Curtin University and The Australian National University (ANU) examined more than 20 years of U. They found persistent changes in several measures of blood chemistry that closely followed the upward trend in atmospheric CO2. The researchers used information from the U. National Health and Nutrition Examination Survey (NHANES), analyzing blood test results from roughly 7,000 people at two-year intervals between 1999 and 2020. 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. Those biological trends occurred as atmospheric CO2 climbed from about 369 parts per million (ppm) in 2000 to more than 420 ppm today. Study author Associate Professor Alexander Larcombe said the results indicate that the body may already be adjusting to changes in the 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," A/Prof Larcombe said. How the Body Responds to More CO2 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.