Methane

Methane is a greenhouse gas that contributes to climate change. The three main greenhouse gases responsible for global warming are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Methane, or CH4, is a colourless and odourless gas consisting of carbon and hydrogen. Methane is emitted through livestock farming, the cultivation of rice, landfills and natural gas mining. As a greenhouse gas, methane is 34 times more potent than CO2 and contributes approximately 20 per cent to the greenhouse effect.

While carbon dioxide and nitrous oxide remain in the atmosphere for hundreds of years, methane breaks down within decades. However, while present in the atmosphere, it has a significant temperature increasing effect. And, because methane continuously enters the atmosphere, its levels remain high. If we succeed in lowering the emission levels, the concentration of methane in the atmosphere will decrease rapidly. This would decrease the thickness of the figurative insulating layer of greenhouse gases, thus slowing down global warming.

Methane is released during the breakdown of organic substances. In the digestive system of animals, for example, during their digestive process. Ruminants - such as cows, goats and sheep - in particular produce high levels of methane and are responsible for some three-quarters of the methane emissions in the livestock sector. They emit the gas from their lungs or stomach (through belching). This process is known as rumen fermentation.

The remaining 25 per cent of the methane emitted in in the livestock sector originates from the manure of cows and pigs. Stored slurry and manure contain compostable organic substances that produce biogas in the absence of oxygen (in liquid). This gas is made up of a little over 50% methane. The methane bubbles to the surface and into the atmosphere.

Of all the methane emitted in the Netherlands, two-thirds originate in the livestock sector. Other key sources are the use of fossil fuels and waste processing. WUR research focuses on reducing methane gas emissions from cows, since 77 per cent of all methane produced by the livestock sector originates from dairy and cattle farms. An additional 14 per cent is emitted by manure storage at pig farms, while other livestock such as chickens, goats, sheep and horses are responsible for the remaining 9 per cent.

Emissions in the livestock sector are a serious issue. Despite many improvements over the last decades, reducing greenhouse gas emissions still requires much work. The farmer is a link in the agro-food chain, made up of suppliers, support services, processing businesses, supermarkets, and, finally, the consumer. Together, they form an interdependent chain in which each party must be addressed on its responsibility to increase the sustainability of the chain.