Our food habits are a big cause of climate change. Because the world wants to eat more animal products these days, the cow, sheep and goat population is growing (3.6 billion at last count), and consequently more emissions are going into the atmosphere. We tend to associate global warming with industry and energy generation, but ruminants shouldn’t be forgotten. Collectively, they produce more than 11% of human-related greenhouse gas emissions, a study last year showed.
This could open up opportunities for farmers to collect and sell methane gas, as suggested by this trial in Argentina, where cow farts were harvested in large bags. But more likely the impact will continue to be negative, and we’ll need a “war on cows” as well as a “war on coal.”
This clip from the Discovery Channel’s Racing Extinction documentary weighs up the problem:
The film says a single cow can fill a 55-gallon bag full of methane every day, and that there are 1.5 billion cows in the world. Methane, of course, is a potent greenhouse gas–20 to 30 times more harmful than CO2, depending on how you measure it.
“Three quarters of agricultural land is used just to feed livestock,” the film says. “When you factor in everything–clearing the land for grazing, feeding and transporting–livestock causes more greenhouse gas than all the direct emissions from the transportation sector.”
Emissions from cattle and sheep are up to 48 times higher per pound of food than those for plant-based products. So, diets with less meat and more vegetation should help cut emissions and keep temperatures down.