A Silent Shift: Our Blood's Response to Rising CO2
In a groundbreaking study, scientists have uncovered a subtle yet significant change in human blood chemistry, suggesting a direct link to the increasing carbon dioxide (CO2) levels in our atmosphere. This finding is a stark reminder of the far-reaching impacts of climate change, affecting not just our environment but our very physiology.
Over two decades of health data, researchers observed a shift in blood chemistry that aligns with higher CO2 exposure. While it may not pose an immediate threat, the trend is concerning. If it persists, certain blood chemistry values could reach the limits of what's considered healthy within the next few decades, according to the study's models.
"The gradual shift in blood chemistry mirrors the rise in atmospheric CO2, which is a driving force behind climate change," explains Alexander Larcombe, a respiratory physiologist from Curtin University. "Our modeling suggests that within 50 years, average bicarbonate levels could approach the upper limit of today's healthy range. Calcium and phosphorus levels could also reach the lower end of their healthy ranges later this century."
Earth's atmospheric CO2 levels have historically been stable, hovering around 280 to 300 parts per million (ppm) for at least the last 150,000 years of human existence. However, in recent decades, this has changed dramatically, with CO2 levels rising from around 369 ppm in 2000 to approximately 420 ppm today.
In human blood, CO2 is converted into bicarbonate. While this compound is essential for maintaining healthy pH levels, Larcombe and his colleague, retired geoscientist Phil Bierwirth, affiliated with the Australian National University, theorized that bicarbonate could also serve as a tracer for atmospheric CO2 levels in the blood.
To test this theory, 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. Their findings confirmed a population-level shift in blood bicarbonate levels, with the average blood concentration of bicarbonate increasing 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 rise paralleled the increase in CO2 over the same time frame.
Interestingly, calcium and phosphorus levels in the cohort showed the opposite trend, 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 a healthy blood pH, the kidneys conserve bicarbonate, and bones can also buffer acid by exchanging minerals like calcium and phosphorus.
At present, these shifts are minor and within the body's tolerable range. However, the parallel rise is notable. "I believe what we're seeing is a result of our bodies not adapting to the new CO2 levels," Bierwirth says. "The normal range is a delicate balance between CO2 in the air, blood pH, breathing rate, and bicarbonate levels. With CO2 levels now higher than ever experienced by humans, it appears to be accumulating in our bodies. This suggests that limiting atmospheric CO2 levels is of vital importance."
The research, published in Air Quality, Atmosphere & Health, highlights the intricate connection between our environment and our health. It prompts us to consider the long-term physiological consequences of climate change and the urgent need for action.
And this is the part most people miss: our bodies are not immune to the changes happening around us. What other silent shifts are we unaware of? What other impacts of climate change are we yet to uncover? These are questions that deserve our attention and action.
What are your thoughts on this study? Do you think we should be more concerned about the potential physiological impacts of climate change? Share your thoughts in the comments below!
