Collective human metabolism produces 2 billion metric tons of CO₂ a year, global study estimates

A University of Bath–led study has estimated that the carbon dioxide produced by humans as our bodies turn food into energy rose by 74% between 1985 and 2015, reaching 2.05 billion metric tons a year. Researchers say the findings could help scientists better understand where carbon comes from, where it goes and how human activity fits into the bigger picture.