Rising CO2 levels are changing our blood chemistry

While it is widely known that rising carbon dioxide emissions have significantly impacted the climate and our ecosystems, scientists recently found a less expected outcome. Increased CO2 levels have altered the chemical balance of human blood, which may have negative long-term health ramifications. The rate at which emissions are increasing also does not allow time for the human body to adapt.

A bloody problem

Increased CO2 levels in the atmosphere have correlated to an increase in bicarbonate (HCO3-) levels and a decrease in calcium (Ca) and phosphorus (P) levels in human blood, according to a study published in the journal Air Quality, Atmosphere & Health. If these trends continue, “blood bicarbonate values could be at the limit of the accepted healthy range in half a century, and Ca and P will be at the limit of their healthy ranges by the end of this century.”

In human blood, CO2 is converted into bicarbonate, which at normal concentrations serves an important role in maintaining healthy pH levels. However, the concentration of bicarbonate increased by about 7%, or 0.34% per year, between 1999 and 2020. Calcium and phosphorus levels dropped by 2% and 7%, respectively. This is because when carbon dioxide dissolves in the bloodstream, it “alters the body's acid-base balance,” said Science Alert. In order to keep the blood pH within its healthy range, the “kidneys conserve bicarbonate, a buffering molecule that helps neutralize excess acidity.” Bones “can also buffer acid by exchanging minerals such as calcium and phosphorus.”

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Code red

Elevated CO2 can lead to a range of adverse health effects. Even “moderate increases in carbon dioxide indoors can affect thinking and focus,” said Earth.com. Certain levels “have been linked to slower decision-making and changes in brain activity in some groups.” It can also “increase stress hormones and cause oxidative stress, which can damage cells.” As far as the changes in our blood, “chronic CO2 retention can lead to metabolic acidosis, which may cause the calcification of kidneys and arteries as the body attempts to manage pH levels,” said Down to Earth. Calcium and phosphorus are also extremely important for our health.

There is a "delicate balance between how much CO2 is in the air, our blood pH, our breathing rate and bicarbonate levels in the blood,” Phil Bierwirth, a retired environmental geoscientist and one of the authors of the study, said in a release. “CO2 in the air is now higher than humans have ever experienced,” and we may “never adapt.” Because of this, it is vital to take action against climate change to reduce emissions and limit the levels of atmospheric carbon.

This is “especially relevant for children and adolescents, whose developing bodies will experience the longest cumulative exposure to rising atmospheric CO2,” said the release. “We’re not saying people are suddenly going to become unwell when we cross a certain threshold,” Alexander Larcombe, a respiratory physiologist and author of the study, said in the release. “But this suggests there may be gradual physiological changes occurring at a population level, and that's something we should be monitoring as part of future climate change policy.”