Atmospheric CO2 climbs, with early signs detected in human blood chemistry
An open‑access study using U.S. health data (1999–2020) finds that rising atmospheric CO2—from about 300 ppm to over 420 ppm and rising ~2 ppm/year—coincides with about a 7% rise in blood bicarbonate, and declines in calcium and phosphorus, the minerals involved in buffering CO2. While the link is correlational and measurement methods varied, authors warn that humans evolved under stable CO2 levels and may be stressed by current changes, potentially pushing buffering chemistry toward unhealthy ranges by around 2076–2100.