The Silent Shift: Our Blood Chemistry is Changing
In a groundbreaking study, scientists have uncovered a subtle yet significant shift in human blood chemistry, suggesting that rising carbon dioxide (CO2) levels are leaving their mark on our very physiology. This revelation is a stark reminder of the far-reaching impacts of climate change.
Using data from a US health database spanning two decades, researchers have identified shifts in blood chemistry that align with increased exposure to CO2. While the changes are currently within safe limits, the trend is concerning. By 2076, some blood chemistry values could reach the edge of what's considered healthy today, according to the study's models.
"It's a gradual shift, but one that mirrors the rise in atmospheric CO2, which is a key driver of climate change," explains Alexander Larcombe, a respiratory physiologist at Curtin University in Australia. "If this continues, we could see average bicarbonate levels approach the upper limit of today's healthy range within 50 years. Calcium and phosphorus levels could also drop to the lower end of their healthy ranges later this century."
The fossil record shows that Earth's atmospheric CO2 levels have been relatively stable for at least 150,000 years, with concentrations hovering around 280 to 300 parts per million (ppm). However, in recent decades, this has changed dramatically, with CO2 levels rising from around 369 ppm in 2000 to approximately 420 ppm today.
In our blood, CO2 is converted into bicarbonate, which helps maintain a healthy pH balance in the body. Larcombe and his colleague, retired geoscientist Phil Bierwirth, affiliated with the Australian National University, theorized that bicarbonate could act as a tracer for atmospheric CO2 levels in the blood.
They analyzed blood chemistry data from the US National Health and Nutrition Examination Survey (NHANES), which collected samples from approximately 7,000 Americans every two years between 1999 and 2020. The results showed a clear shift: the average blood concentration of bicarbonate rose from 23.8 to 25.3 milliequivalents per liter over the study period, an increase of about 7 percent, or 0.34 percent per year. This paralleled the rise in CO2 over the same time.
Conversely, calcium and phosphorus levels in the cohort decreased, with calcium dropping by 2 percent and phosphorus by 7 percent. This could be related to the body's acid-base balance, which is disrupted when carbon dioxide dissolves in the bloodstream. To maintain blood pH within a healthy range, the kidneys conserve bicarbonate, and bones can also buffer acid by exchanging minerals like calcium and phosphorus.
"Our bodies are not adapting to these changes," Bierwirth says. "The normal range of CO2 in the air that we're adapted to may have been surpassed. The balance between CO2 in the air, our blood pH, breathing rate, and bicarbonate levels is delicate. With higher CO2 levels in the atmosphere, it appears to be building up in our bodies. This suggests that limiting atmospheric CO2 levels is vitally important."
The research, published in Air Quality, Atmosphere & Health, highlights the need for further investigation into the long-term physiological impacts of rising CO2 levels. It's a reminder that the effects of climate change are not always visible, but they are real and potentially far-reaching.
What are your thoughts on this study? Do you think we should be more concerned about the subtle impacts of climate change on our health? Share your thoughts in the comments below!
