1.5 BILLION COWS

The world is home to about 1.5 billion cows, most of them bred and raised for the meat and dairy industry. Each of them has a quadripartite stomach, whose largest section is called rumen. 

An adult cow’s rumen can hold about 150 to 200 litres, and is populated by a staggering collection of microorganisms (25 billion bacteria per gram of volume), tasked with breaking down vegetal fibres through fermentation. 

A by-product of rumen fermentation is hydrogen; a specific bunch of rumen-dwelling microbes, called methanogens, convert that hydrogen into methane. 

Methane is subsequently expelled through the cow’s front end – through burping – or through the cow’s backdoor – via farting. A cow burps and farts between 160 to 320 litres of methane per day. That is bad news for the environment.

While much of the climate change debate (rightly) focuses on slashing carbon dioxide (CO2) emissions, methane still makes up 16 per cent of global greenhouse gas emissions, according to 2015 figures from the Intergovernmental Panel on Climate Change - link