Human Breathing Produces 2.05 Billion Tonnes Of CO₂ Annually
What Happened
A University of Bath-led study published in The Lancet Planetary Health estimates that CO₂ produced by human metabolism rose from 1.18 billion tonnes in 1985 to 2.05 billion tonnes in 2015, a 74% increase. Population growth accounted for more than 60% of the rise. Researchers combined thousands of real-world metabolic measurements across different ages with global population and body-weight data to estimate humanity’s total output.
Key Takeaways
This does not mean human breathing is driving climate change. The CO₂ we exhale largely comes from carbon recently absorbed by plants and returned through food, unlike fossil fuels, which release carbon stored underground for millions of years.