Sunita Somvanshi
Rising carbon dioxide in the atmosphere may already be leaving a measurable mark inside the human body. Scientists analysing more than two decades of U.S. health data found that blood bicarbonate levels have climbed about 7 per cent since 1999, even as calcium and phosphorus edged downward – shifts that track the rise in atmospheric CO2.
The study, published in Air Quality, Atmosphere and Health by researchers at The Kids Research Institute Australia, Curtin University and the Australian National University, drew on the U.S. National Health and Nutrition Examination Survey (NHANES). It covered blood tests from roughly 7,000 people at two-year intervals between 1999 and 2020. Over that span, atmospheric CO2 rose from about 369 parts per million in 2000 to more than 420 ppm today, the authors note in the published paper.
Bicarbonate is a blood marker tightly linked to carbon dioxide in the body, so a steady rise is biologically plausible as the atmosphere – and, by extension, what we breathe – changes. Associate Professor Alexander Larcombe said the results suggest the body may already be adjusting to a shifting atmosphere. The concern is where the trend ends: one key marker could approach the upper bound of its healthy range within decades, a warning echoed by reporting from CNN on the same research.
The implications fall squarely on younger generations. Because their bodies are still developing, children and teenagers will accumulate the greatest lifetime exposure to elevated CO2, making them the group to watch. The finding reframes climate change as not only an environmental threat but a slow-moving public-health one that begins before a child is fully grown.
Exactly how a changing atmosphere translates into altered blood chemistry – and whether the shift carries clinical consequences – remains an open question. The authors call for continued monitoring as CO2 continues its climb, noting that the data so far point to the body keeping pace with a planet that is warming and acidifying faster than at any point in human history.
