To understand the methane of cows, you have to look at the side of the burps

A cow transforms grass through a digestive system that is home to a multitude of microorganisms. In the rumen, fermentation takes place without oxygen and makes it possible to draw resources from plants rich in fiber.

Some microorganisms produce methane during this operation. The CLEAR Center at the University of California at Davis explains that enteric gas is expelled by eructation: burps therefore occupy a central place in history, often mistakenly summarized as flatulence.

Comparing a cow to a car then requires specifying the period, the emissions retained and how to convert the effect of the different gases. A number of kilograms of methane is not automatically the same number of kilograms of CO₂ equivalent. The real mechanism is already amazing: an invisible activity of microbes becomes a climate issue at the scale of the herds.