Portuguese 
English 
Spanish 
4 min of reading 
0 comments 
Researchers from Australia analyzed 21 years of blood tests from 7 thousand people and saw a CO2 marker rise at the same rate as the gas in the atmosphere. Their message is twofold: the trend is concerning, but for now, it is a hypothesis, not a sentence.
A study published in February 2026 detected that CO2 in human blood has been rising steadily over the past two decades, at the same rate as the gas increases in the atmosphere. The research, conducted by The Kids Research Institute Australia in partnership with Curtin University and the Australian National University, analyzed tests from about 7 thousand people and concluded that if the trend continues, a CO2 marker in the body could exceed the healthy limit in around 50 years. It is the first time a large-scale study has tracked carbon dioxide in the human body and found this pattern.
The data was published in the scientific journal Air Quality, Atmosphere and Health and was reported by outlets like CNN in March 2026. Between 1999 and 2020, bicarbonate in the blood, which is the main form in which CO2 circulates in the body, rose about 7 percent, going from 23.8 to 25.3 milliequivalents per liter. In the same period, CO2 in the atmosphere jumped from about 369 parts per million in 2000 to over 420 today, the highest level in the history of our species.
How the gas from the air ends up in your blood
The logic is simpler than it seems. With more CO2 in the air, we breathe more CO2 with each inhalation. This excess makes the blood slightly more acidic, and the body reacts by trying to balance itself: the kidneys produce and retain more bicarbonate to neutralize the acidity. That’s why this marker has risen, and that’s how carbon dioxide in the human body ends up becoming a number that appears on a blood test.
-
Australia delivers to the US Navy the Speartooth, a giant submarine drone up to 12 meters long capable of operating covertly for 2,000 km, diving to 2,000 meters, and acting as an unmanned underwater weapon in surveillance, reconnaissance, and attack missions.
-
Russia moves nuclear weapons to Belarus, deploys submarines, fighter jets, and giant missiles, turning a military exercise into a heavy message for NATO.
-
USA sends nuclear aircraft carrier Nimitz to the Caribbean and increases diplomatic suspense with Cuba after new accusation against Raúl Castro reignites historical tension
-
Invented in 1910 and almost forgotten, the rooftop wind turbine cools the house using only wind and rising heat, but disappeared from buildings due to noise, condominium rules, and stricter building codes, and now many people want to bring it back.
The problem is that this balance comes at a cost. In the same studied interval, calcium in the blood dropped about 2 percent and phosphorus about 7 percent. One of the researchers’ hypotheses is that the bones come into play as buffers, releasing minerals to help buffer the acidity, which would help explain this decrease.
The warning weighs more on children
The authors make a point of highlighting who is most exposed: today’s children and adolescents. As they will live the entire coming decades breathing air increasingly loaded with CO2, their accumulated exposure time is the greatest of all.
In the study’s projections, maintaining the current pace, the bicarbonate in the blood could reach the top of the range considered healthy around 2076. Calcium and phosphorus, decreasing, could approach the minimum healthy limit by the end of this century.
Attention: it is still a hypothesis, not a certainty
Here comes the honest part that many headlines out there hide. The authors themselves, writing on the site The Conversation, made it clear that the study shows a strong correlation, not a proven cause. In other words, they caught two curves rising together, the CO2 in the air and the bicarbonate in the blood, but this does not yet mean that one definitively causes the other.
Other factors, such as dietary changes, population weight, and kidney function over the years, may also be pushing these numbers. The very title of the work speaks of a “potentially” toxic atmosphere, and the scientists’ summary is uncomfortably honest: the signal is worrying, but they still do not know for sure what it means. It’s a call to investigate further, not a diagnosis to panic over.
Why this matters anyway
Even as a hypothesis, the discovery opens a new door. Until now, the conversation about climate change revolved almost entirely around temperature, drought, flooding, and sea level. This study suggests, for the first time with large-scale population data, that the excess carbon dioxide in the human body may be leaving a measurable mark.
If confirmed by new research, it would be another reason, now very personal, to address the amount of carbon that humanity releases into the air. Not as just a climate problem out there, but as something that circulates, literally, in our veins.
Be the first to react!