The air outside is getting heavier. Not in the humidity sense, but in the chemistry sense. And it turns out that shift is showing up in our bloodwork.
Researchers think human physiology is already reacting to the changing composition of the atmosphere We are seeing subtle signatures in standard blood markers that track with rising carbon dioxide It is a slow process but it is happening.
What The Data Actually Says About Rising CO2 And Health
A team from The Kids Research Institute Australia Curtin University and The Australian National University dug into decades of US data They didn’t guess at it. They used hard numbers from the US National Health and Nutrition Examination Survey NHANES.
They looked at about 7 000 people tested every two years between 1 9 9 9 and 2 0 2 0.
The results are distinct. Since 1 9 9 serum bicarbonate levels rose by roughly seven percent Bicarbonate is the body’s way of carrying carbon dioxide around As atmospheric CO2 climbed from about 369 ppm in 2 0 0 0 to over 420 ppm now our blood chemistry followed suit.
Meanwhile calcium and phosphorus concentrations dipped.
Why does this matter? Because these minerals are essential for bone strength and nerve function. Bicarbonate keeps the pH of the blood stable. It is a buffer. A buffer against the acidifying effects of extra carbon dioxide in the system.
Why Children And Adolescents Face Greater Long Term CO2 Risks
Here is where it gets sticky.
Kids aren’t just smaller adults. They are developing systems exposed to the environment for the longest period of time. Their bodies face the cumulative impact of rising CO2. If you live another seventy years the total dose of extra carbon exposure is higher than someone born thirty years ago.
Associate Professor Alexander Larcombe notes that this gradual shift mirrors the climate change driver itself. The atmospheric carbon increase drives the physiological change. It is a direct link in the data.
Is the body broken? Not necessarily. It is compensating. The body holds more bicarbonate to keep pH stable despite higher CO2 intake or exposure But maintaining that compensation for decades has a cost.
If the current trajectory continues modeling suggests average bicarbonate levels could hit the upper limit of the healthy range within fifty years Calcium and phosphorus might bottom out at the lower limits of healthy ranges late this century.
That sounds like a medical warning. It is. But the cause is atmospheric.
Why Causal Links Remain Uncertain In Climate Biology Studies
We evolved when the atmosphere had roughly 280 to 3 0 ppm of CO2. We never knew anything else until recently. The last ten years have seen an average increase of 2 6 ppm annually 202 4 saw a spike of 3 5 ppm.
Dr Phil Bierwirth an environmental geoscientist from ANU is clear on the limitations. The study does not prove direct causation in a vacuum. There are other factors diet stress genetics. But the population trend is consistent enough to ignore no one wants to ignore this.
Bierwirth offers a stark perspective.
I actually think that what we are seeing are our bodies are not adapting.
He suggests we adapted to a specific CO2 range that we have now exceeded. The delicate balance between air CO2 blood pH breathing rate and bicarbonate is stressed. The CO2 builds up in the body. We might simply be unable to adapt to this new normal. Which brings up a question that isn’t usually asked at climate conferences. Can we ever adapt if we never limit atmospheric CO2 levels?
Why Health Biomarkers Belong In Climate Policy Discussions
We tend to talk about climate risk in terms of weather. Storms fires floods. We talk about sea level rise and crop failures. We rarely talk about our internal biology as a climate indicator.
This research argues for a shift in how we measure success or failure in climate policy. Atmospheric CO2 should be treated as a public health variable. Not just an environmental one.
Larcombe stresses that no one is suddenly going to get sick crossing a threshold. There is no cliff. It is a slope. Gradual physiological changes at the population level are happening now. They warrant monitoring.
We need to watch biomarkers alongside temperature records. It clarifies the biological toll of gradual environmental shifts over long periods. Cutting emissions isn’t just about saving polar bears or stopping hurricanes. It might be about keeping human blood chemistry within functional parameters.
The potential physiological effects of rising CO2 need to enter the room at climate policy meetings. Not as a sidebar. As a core health metric.
We do not know where this line ends yet. The data only points us forward into higher numbers and tighter physiological margins. What we do now determines whether that slope stays gentle or turns steep. The choice remains in how we treat the air we share.
