Rising CO2 Levels Detected in Human Blood: Curtin University and Kids Research Institute Link Atmospheric Rise to Key Biomarkers

Groundbreaking Insights from Curtin University and Kids Research Institute

A pioneering study led by researchers from Curtin University and The Kids Research Institute Australia has uncovered startling evidence that rising atmospheric carbon dioxide (CO2) levels are now detectable in human blood chemistry. Published in the journal Air Quality, Atmosphere & Health, the research analyzed over two decades of data from the U.S. National Health and Nutrition Examination Survey (NHANES), revealing gradual shifts in key biomarkers that mirror global CO2 trends. Associate Professor Alexander N. Larcombe, affiliated with Curtin University's School of Population Health and the Wal-yan Respiratory Research Centre at The Kids Research Institute, spearheaded the effort alongside Dr. Phil N. Bierwirth from the Australian National University (ANU). This collaboration highlights how Australian higher education institutions are at the forefront of linking climate science with human physiology.

The findings indicate that average serum bicarbonate levels—a critical blood marker tied to CO2—have risen by about 7% from 23.8 mEq/L in 1999 to 25.3 mEq/L in 2020. Concurrently, serum calcium and phosphorus levels have declined by roughly 2% and 7%, respectively. These changes parallel the surge in atmospheric CO2 from approximately 369 parts per million (ppm) in 2000 to over 420 ppm today, as measured at global observatories like Australia's Cape Grim baseline station.

"What we're seeing is a gradual shift in blood chemistry that mirrors the rise in atmospheric carbon dioxide which is driving climate change," explains A/Prof Larcombe. This discovery underscores the role of universities like Curtin in translating environmental data into actionable health insights.

Understanding Serum Bicarbonate: The Body's CO2 Buffer Explained

To grasp the significance, it's essential to understand serum bicarbonate (HCO3-), the primary buffer maintaining blood pH between 7.35 and 7.45. When atmospheric CO2 enters the lungs, it dissolves in blood to form carbonic acid (H2CO3) via the enzyme carbonic anhydrase: CO2 + H2O → H2CO3 → H+ + HCO3-. The kidneys regulate HCO3- levels to neutralize excess acidity from rising CO2, preventing respiratory acidosis.

In pre-industrial times, humans evolved under stable atmospheric CO2 of 280-300 ppm. Today's levels exceed 420 ppm, with Australia's Cape Grim recording 423.3 ppm in January 2026—a 3.5 ppm jump in 2024 alone. The body compensates by retaining more HCO3-, but sustained elevation risks demineralization of bones (releasing calcium and phosphorus) and long-term imbalances.

• Step 1: Inhaled CO2 diffuses into blood, forming H2CO3.
• Step 2: Dissociation produces H+ (acid) and HCO3- (base).
• Step 3: Kidneys reabsorb HCO3- to stabilize pH, elevating serum levels.
• Step 4: Chronic exposure prompts bone buffering, lowering Ca and P.

This process, detailed in the Curtin-led study, signals early physiological adaptation—or overload—to a changing atmosphere.

Methodology: Analyzing Decades of NHANES Data

The researchers examined biennial NHANES cycles from 1999-2020, aggregating serum HCO3-, calcium, and phosphorus from ~7,000 participants per cycle (ages 0-80+). Trends were correlated with Mauna Loa CO2 records, showing parallel increases (0.34% annual HCO3- rise vs. ~0.5% CO2). Linear modeling projected future trajectories assuming current emission rates persist.

While causation isn't proven, population-wide consistency rules out confounders like diet or demographics. Australian institutions like Curtin excel in such big-data epidemiology, leveraging NHANES for global insights applicable to local populations.

Projections: A Tipping Point by Mid-Century?

Extrapolating trends, average HCO3- could hit the upper healthy limit (30 mEq/L for venous blood) by 2076—potentially sooner with accelerating emissions. Calcium may reach 2.1 mmol/L (lower limit) by 2099, phosphorus 0.81 mmol/L by 2085. By mid-century, at 500-600 ppm CO2, blood chemistry could enter 'unhealthy' zones, risking toxicity.

Australia's emissions projections aim for 43% reduction by 2030, but global trends threaten reversal.

Potential Health Risks: From Cognitive Decline to Organ Damage

Elevated CO2/HCO3- may trigger endoplasmic reticulum stress, oxidative damage, inflammation, and calcification. Animal studies show cognitive deficits at 400-1000 ppm; humans spend 87% indoors where levels hit 700-3000 ppm. Risks include anxiety, cardiovascular issues, and cancer promotion. Dr. Bierwirth warns: "Our bodies may not adapt; limiting CO2 is vital."

Read the full study

Why Children Face the Greatest Threat

The Kids Research Institute's focus amplifies concerns for youth. Developing lungs, brains, and bones are vulnerable; prior Australian mouse studies showed lung damage at projected CO2 levels. Cumulative exposure over lifetimes could impair growth, cognition, and respiratory health—prioritizing pediatric research at institutions like Curtin.

Australia's Role: Leading Climate-Health Research

Australia monitors CO2 at Cape Grim (423 ppm Jan 2026), informing global baselines. Unis like Curtin, ANU, and UWA drive interdisciplinary work. Telethon Kids Institute (affiliated) pioneers pediatric environmental health, training future researchers via higher ed research jobs.

Stakeholder Perspectives: Experts Weigh In

A/Prof Larcombe urges monitoring biomarkers in policy: "Gradual changes demand vigilance." Global experts echo urgency; indoor CO2 studies link 1000 ppm to 15% cognitive drop. Australian higher ed must expand such cohorts.

• Respirologists: Ventilation limits CO2 excretion.
• Endocrinologists: Bone demineralization risks osteoporosis.
• Climate scientists: Aligns with 2.6 ppm/year rise.

Solutions: Emission Cuts and University-Led Innovations

Australia targets net zero by 2050 via renewables (82% by 2030). Unis contribute: UNSW's CO2-to-fertiliser, Sydney's Net Zero Institute. Explore higher ed career advice in green tech; roles in research jobs abound.

CSIRO Cape Grim Data

Future Outlook: Monitoring and Mitigation in Higher Education

Ongoing NHANES-style studies in Australia could track local biomarkers. Curtin calls for CO2 as a public health metric. For academics eyeing climate-health, Western Australia university jobs at Curtin offer opportunities. Reducing emissions safeguards generations—higher ed leads the way.

In summary, this Curtin-Kids Research breakthrough reframes CO2 as a direct physiological threat, urging policy integration of blood biomarkers. Australian universities exemplify research excellence; join via higher-ed-jobs, rate-my-professor, or career advice.