Agriculture causes 14% of the world’s greenhouse gases, a big portion of which comes from methane, which is 23 times more powerful than carbon dioxide. And it is estimated that methane output could increase by 60% by 2030. It turns out that cows, which emit methane primarily through belching with a smaller amount through flatulence, are a major contributor to greenhouse gases. Estimates of how much methane a cow emits each day vary widely ranging from 26 gallons to 132 gallons of methane per day – generally considered comparable to the amount of pollution daily produced by a car. Cows belch so much methane because they are ruminates, having four stomachs in which they digest their food. Their stomachs are filled with bacteria that help with digestion but also produce methane. Since much of our greenhouse gases result from human-created activities, have you ever wondered how a cow, one of God’s creatures, is making such a profound contribution to global warming? It turns own that we humans and our manipulation of nature plays a big role here too. Click here.  Accordingly to How Stuff Works, early grazing areas for cows were filled with a variety of grasses and flowers that grew naturally and offered a diverse diet for cows. When eating this natural bounty, cows did not emit that much methane. However, cattle ranchers figured out that feeding cows could be more efficient if they reseeded pastures with perennial ryegrass. Aided by artificial fertilizers, ryegrass grew quickly and in huge quantities. But ryegrass, referred to as the “fast food” of grasses, lacks the nutritious content of other grasses and prevents more nutritious grasses from growing. For cows, ryegrass is much more difficult to digest, it ferments in their stomachs, and it causes the cow to belch and fart.

Scientists are now studying different ways to reduce methane produced by cows. One study, which is examining whether garlic added to cow feed will reduce methane gas, suggests that garlic may reduce it by as much as one-half. Other studies show positive results where cows are fed more diverse, naturally growing and nutrient grasses and other plants.

Even if scientists are able to prescribe proven ways to reduce methane gas from cows, getting cattle ranchers to adopt these methods will be a struggle. The cost of re-planting naturally growing grasses and plants will be substantial and most likely be resisted. And attempts to tax methane production from livestock have so far been unsuccessful. While the EPA briefly floated a US methane tax on cows,  it appears to have quickly died, possibly because a tax proposed on methane in New Zealand, where 34% of greenhouse gases come from livestock, met resounding defeat in 2003 when it became commonly known and derided as the “fart tax.”