nature & planetScienceDaily

Human bodies produce 2 billion metric tons of CO2 a year just by staying alive

from ScienceDaily

Humans collectively produce more than 2 billion tonnes of carbon dioxide annually just by turning food into energy, a 74% increase over three decades largely driven by population growth. Unlike fossil fuel emissions, however, the CO2 we exhale is part of the natural carbon cycle, and scientists say measuring it more accurately could improve climate models.

explained

Carbon dioxide is a chemical compound with the chemical formula CO2. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle, atmospheric CO2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater.

It is a trace gas in Earth's atmosphere at 428 parts per million (ppm), or about 0.043% (as of July 2025) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels is the main cause of these increased CO2 concentrations, which are the primary cause of climate change.

From Wikipedia: Carbon dioxide (CC BY-SA 4.0) ↗
so what

The figure is a surprise because it shows how much carbon moves through living bodies every year. Distinguishing this natural cycle from fossil fuel emissions could sharpen how scientists model the climate.

more on this

Illustrative photo · RegisFrey, CC BY-SA 3.0, via Wikimedia Commons