Is it a boat? Is it a plane? No, it’s a cow!? Livestock are responsible for nearly one fifth of greenhouse gas emissions, more than all forms of transportation combined, and cows are one of the biggest culprits. Their weapon of choice: the mighty methane burp. Methane (CH₄), is one of the most potent greenhouse gasses at trapping heat and therefore is one of the biggest contributors to global warming. When compared to the same volume of carbon dioxide, methane has 25 times greater impact on climate change. Each cow can produce up to 150kg of methane per year and with 98 million cows in the world that’s a lot of burping and a lot of methane. Methane production comes from the digestion of plant components such as cellulose (large carbohydrates found in the cell walls of the plants). Unlike humans, cows can digest these plant components due to a large portion of the stomach called the rumen, that contains microbes such as methanogens. In a fermentation process the microbes digest the cellulose to provide nutrients to the cow as well as releasing carbon dioxide and hydrogen. Any remaining hydrogen is soaked up by the methanogens to form methane.
In order to tackle this global concern, scientists are experimenting with cows on the inside and out. Areas of research include testing a variety of feed and food additives that can reduce methane production as well as possible vaccinations to reduce the burping impact. Food additives containing nitrate are thought to be a possible solution to this problem as the extra nitrogen will cause the formation of ammonia (NH₃), rather than methane. A new study showed how the nitrogen supplement known as 3NOP (3-nitrooxypropanol), can reduce methane emissions from cows by 30%. Not only did the 3NOP decrease methane production it also enhanced the digestibility of the cow feed. This meant that cows could retain more energy and nutrients from their food and therefore gain more weight than those that didn’t have the supplement in their feed. If further testing shows that the additive is not harmful to the cow in the long term this supplement could be used to provide increase animal productivity whilst decreasing greenhouse gas emissions. Another technique for improving productivity is to breed cows that are more efficient in producing milk. If demand for milk and other dairy products can be met by fewer cows that would mean less burping, which would mean less methane. In addition, there are projects investigating breeding cows that are less flatulent. By using a specially designed fume hood that collects cow burps, researchers can see which cows are producing the least methane and through selective breeding can produce animals that release up to 25% less than average.
But it’s not just the burping that’s causing all of the gas. The agriculture industry produces a lot of greenhouse gasses from pesticides, fertilisers, fuel used for equipment and emissions released in food transportation. As well as that, meat production requires a lot of land with agriculture being attributed to 80% of the deforestation worldwide. Cows are the biggest culprits; producing 1kg of beef requires 15 times as much land as producing 1kg of cereals and 70 times as much land as 1kg of vegetables. Not only is deforestation reducing the amount of carbon dioxide that is sequestered from the atmosphere, if forests are cleared using the popular ‘slash and burn’ technique then more carbon dioxide will be released.
The human population is still growing and developing countries are moving to a more Westernized diet with more meat content. This means the demand for meat is only going to increase and therefore the contribution that cows and other animals have to global warming will also rise. In order to meet demands whilst reducing greenhouse gas emissions these techniques must be developed further to produce a better cow that burps less. However, it’s not just up to the boffins to bust the burp, we must also adapt our eating habits to a more vegetable-based diet in order to decrease the demand for meat and ultimately reduce our carbon footprint.