Monday, February 15, 2016


Agriculture is responsible for an estimated 14 percent of the world's greenhouse gases. A significant portion of that is methane, caused principally by the belching (& flatulence) of the world's 1.5 billion dairy cows and bulls and also by billions of other grazing animals, both farmed and wild. Methane is also produced when the manure from these animals is stored in lagoons or holdings tanks.

Graphics credit to @OatJack.

Pie chart of U.S. methane emissions by source. 29 percent is from natural gas and petroleum systems, 26 percent is from enteric fermentation, 18 percent is from landfills, 10 percent is from coal mining, 10 percent is from manure management, and 8 percent is from other sources.

Note: All emission estimates from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013.

Methane (CH4) is the second most prevalent greenhouse gas emitted in the United States from human activities. In 2013, CH4 accounted for about 10% of all U.S. greenhouse gas emissions from human activities. 

Methane is emitted by natural sources such as wetlands, as well as human activities such as leakage from natural gas systems and the raising of livestock. 

Natural processes in soil and chemical reactions in the atmosphere help remove CH4 from the atmosphere. 

Methane's lifetime in the atmosphere (12 years) is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 on climate change is more than 25 times greater than CO2 over a 100-year period.

The infographics (above/ credit to @OatJack) compares farmed animals in the UK and their contribution to methane emissions per animal per year in kilograms. A dairy cow emits over twice the amount of methane than a beef cow and is by far the highest contributor of all the animals studied
Data from the UK GHG Inventory report 1990-2012.

'Global emissions of methane were estimated to be between 76 – 92 Tg per year (1 Tg = 1 million metric tonnes). This is roughly equal to ~10-15 % of global methane emissions, which in turn is ~15 % of global GHG emissions. Methane is a more potent GHG than CO2, which means that gram for gram methane warms the atmosphere more than CO2. Methane also has a much shorter lifetime in the atmosphere compared to CO2 (~10 years compared to 100s of years) which will produce more rapid impacts on the global climate. This also means that any reductions in methane emissions will see a faster decrease in atmospheric concentrations than compared to CO2

Beef cattle and pasture/rangeland distribution in the continental United States. Source: USGCRP (2009)



Statistics vary regarding how much methane the average dairy cow expels.

According to one Danish study, the average cow produces enough methane per year to do the same greenhouse damage as four tons of CO2. The average car, by contrast, produces just 2.7 tons. Multiply that by the planet’s 1.5 billion cattle and buffalo and 1.8 billion smaller ruminants and you have the methane equivalent of two billion tons of CO2 per year

Silence the Cows and Save the Planet By Jeffrey Kluger  (Time March 30, 2011)   

 Estimates vary from 100-200 liters a day (26-53 gallons) to 500 liters ( 132 gallons) a day. This amount of methane is comparable to that produced by a car in a day. Another source estimates one cow's contribution to climate change every year is the equivalent of driving more than 7500 miles in the average car.

The U.S. Food and Agriculture Organization (FAO) says that agricultural methane output could increase by 60 percent by 2030  


Cows, goats, sheep, buffalo and camels belong to a class of animals called ruminants. Ruminants have four stomachs and digest their food in them instead of in their intestines, as humans do. Ruminants eat food, regurgitate it as cud and eat it again. 

The plant diet of cows and other ruminants is high in cellulose, which cannot be digested by the ruminant itself. However, ruminants have a symbiotic relationship with colonies of microorganisms, called methanogens, which live in their gut and break down the cellulose into carbohydrates.. These carbohydrates provide both the microbial community and the ruminant with an energy source. Methane is produced as a by-product of this process.A common misconception is that the cow’s rear end emits methane, however the vast majority is released orally. Researched carried out by Grainger et al. in 2007 found that 92-98 % was emitted orally (I won’t go into detail about how they found that out!). 


Adressing this global problem is not easy. In the short-term it means reducing the number of animals and shifting both the diet of humans and animals. In other words, encouraging people to eat less meat, or eat meat from animals that don't produce so much methane (kangaroos, for instance), or become vegetarians or vegans.

'Changing the cow's diet is the subject of much scientific research in different countries. In the UK the Department of Environment, Food and Rural affairs (DEFRA) scientists suggest adding maize silage, naked oats and grasses higher in sugar.  
Maize silage, which, as its name suggests, is produced by fermenting corn shuckings in a silo or in covered heaps, can reduce tailpipe emissions by as much as 6%. Higher-sugar grasses can mean a 20% reduction, and naked oats—or oats without husks—reduce methane by a whopping 33 percent. 
Changing the diets of farm animals around the globe will not be easy. U.K. animals already do eat some of the low-gas fare, but it makes up only about 25% of their diet. This would have to be tripled to 75% to make the advertised difference in subsequent wind. That’s an increase that, in the U.K. at least, the government seems willing to push.'
 Silence the Cows and Save the Planet By Jeffrey Kluger  (Time March 30, 2011)
At Denmark's Aarhus University  they are working on four-year project to see if adding organic Greek oregano to the cow's diet can reduce the methane They say the plant has high contents of essential oils ans is a natural remedy for reducing the gas produced due to its antimicrobial properties
Kai Grevsen, project manager said: "The goal is to show that we can reduce methane emissions from dairy cows by up to 25% by adding oregano to the feed." He added: "Should the results be positive, they can be implemented on all cattle farms, conventional and organic, so there is a really large potential."

They will analyse the milk from cows being used in the study, to see if it can be used an 'environmentally-friendly' product. Oregano reduces the fatty acid composition of the milk, and researchers will be using volunteers to test its taste too.

Global meat production is projected to increase to 465 million tonnes by the year 2050. That is more than double the amount produced in 2001 at 229 million tonnes.

Oregano could prevent cows from burping methane and ultimately destroying the planet
By Matt Atherton/International Business Times (February 9, 2016)


Mobilizing Bright Science for Project “Clean Cow”

More sustainable farming through lower emissions and increased milk production

Every day a dairy cow will emit some 500 liters of methane – a potent greenhouse gas. These emissions not only pollute the environment, they also consume 10% of the energy a cow could otherwise use for milk production. So we focused a broad combination of competences and bright minds on producing a feed additive to address this issue: Trials indicate that this additive effectively reduces the cow’s daily methane production by over 30%.

According to Science Magazine, a food supplement added to the diets of cows could reduce their gases by roughly 30%. It is called the 3NOP (3-nitrooxypropanol) compound, developed by DSM Nutritional Products from The Netherlands, one of the world’s leading suppliers of feed additives. The 3NOP supplement blocks an enzyme necessary to cause the last step of methane production by the microbes in the rumen (first stomach of the cow). Regulators are now reviewing the product.

Methane Reduction Supplements Could Help Save Earth

'With the development of large-scale agriculture in the mid-20th century, farming became a big business for some companies. Farms became consolidated into large enterprises with many thousands of animals across large acreages.
'Initially, grazing areas were filled with a variety of grasses and flowers that grew naturally, offering a diverse diet for cows and other ruminants. However, in order to improve the efficiency of feeding livestock, many of these pastures became reseeded with perennial ryegrass. With the aid of artificial fertilizers, perennial ryegrass grows quickly and in huge quantities. The downside is that it lacks the nutritious content of other grasses and prevents more nutritious plants from growing. One commentator called it the "fast food" of grasses 
'This simple diet allows many cows to be fed, but it inhibits digestion. The difficult-to-digest grass ferments in the cows' stomachs, where it interacts with microbes and produces gas A perennial ryegrass diet also results in a significant number of weak and infertile cows, which have to be killed at a young age.  
'Because of concerns about ruminant diets, many researchers are investigating ways to alter what livestock eat and to mix the best of old cow pastures -- diverse, naturally growing, nutrient rich grasses and plants -- with the best of the new -- fast-growing and resistant to invasive species.  
'A three-year study by Welsh scientists,examined whether adding garlic to cow feed can reduce their methane production. Results indicated that garlic cuts cow flatulence in half by attacking methane-producing microbes living in cows' stomachs.  
'At the University of Hohenheim in Germany, scientists created a pill to trap gas in a cow's rumen and convert the methane into glucose. However, the pill requires a strict diet and structured feeding times, something that may not lend itself well to grazing.'



In New Zealand, where cattle and sheep farming are major industries, 34 percent of greenhouse gases come from livestock. In 2003, the government proposed a flatulence tax, which was not adopted because of public protest.

A vaccine to lower greenhouse gas emissions in cattle has reached testing stage in New Zealand. Strategy and investment leader for sustainability at Dairy NZ, Rick Pridmore, said the development of a vaccine could mean a reduction in methane emissions from cows by between 25 and 30 per cent. "We're getting very close to coming up with a possible vaccine and we are doing animal testing right now," Mr Pridmore said.

According to Mr Pridmore, the vaccine works by targeting methanogens, the gut bacteria which produce methane. "Basically you try to find a protein or a peptide that is on these methanogens," he said. "You then create an auto-immune response to that, so the body attacks itself. "A recent study, that New Zealanders helped to lead, shows that the predominant bacteria we are trying to knock down are also very common throughout the world."So that means a successful vaccine will probably work [in herds] worldwide."


With millions of ruminants in Britain, including 10 million cows, a strong push is underway to curb methane emissions there. Cows contribute 3 percent of Britain's overall greenhouse gas emissions and 25 to 30 percent of its methane. 

Image result for COW METHANE

In 2010, the U.N. proposed a global levy on livestock’s methane emissions, a measure that was promptly — and unavoidably — dubbed a fart tax in the press. 


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