Rising carbon dioxide levels are being detected within the human body,
with new research warning a key blood marker for the gas could near its healthy limit within decades if current trends continue.

The findings are especially relevant for children and adolescents, whose developing bodies will experience the longest cumulative exposure to rising atmospheric CO₂

Bicarbonate plays a central role in maintaining the body's acid–base balance.

When CO₂ levels rise, the body retains more bicarbonate to stabilize blood pH.

Over time, however, sustained compensation may carry physiological consequences.

"If current trends continue, modeling indicates average bicarbonate levels could approach the upper limit of today's accepted healthy range within 50 years," Prof Larcombe said.

"Calcium and phosphorus levels could also reach the lower end of their healthy ranges later this century."

Humans evolved in an atmosphere containing roughly 280–300 ppm of CO₂.

The average annual increase over the past decade has been about 2.6 ppm per year, with 2024 recording a 3.5 ppm rise.

Fellow Author Dr. Phil Bierwirth, a retired environmental geoscientist who is affiliated with the ANU Emeritus Faculty,
said while the study does not prove direct causation,
the consistent, population-wide trends are difficult to ignore.

"I actually think that what we are seeing is because our bodies are not adapting," Dr. Bierwirth said.

"It appears we are adapted to a range of CO2 in the air that may now have been surpassed"
https://phys.org/news/2026-02-carbon-dioxide-human-blood.html