Cows, Methane &
Global Warming 

Newspapers and magazines have, over the years, reported on the fact that Methane is a more potent gas than Carbon Dioxide (CO₂) the articles go on to point out ruminant livestock “passing wind” as being the most significant contributor to the release of additional methane into the atmosphere. This appears to have brought about the call for a reduction or complete cessation of livestock farming and for everyone on planet earth to follow a vegetarian diet. These calls seemingly focus on a handful of justifiable reasons, yet few take account of the “bigger picture“ or of the possible results or wider implications of such an action.

Atmospheric Methane and Carbon Dioxide

The impact of global warming is a major concern for the long-term welfare of humans, we are informed repeatedly that we must cut down our own emissions of “CO₂”. It seems most people take that statement at face value, CO₂ is the crucial greenhouse gas. What few realise is that figures quoted are in fact eCO₂ and refer to all greenhouse gases, where other gases, such as methane, have been converted into equivalents of CO₂. Presumably it was thought easier for the majority of people to understand, though it has led to confusion about the impacts each of the greenhouse gases have on the planet.

Levels of atmospheric carbon dioxide have changed since the industrial revolution of the 1750’s, with an increase of around 37% CO₂ and 172% CH₄. Longevity of each of these gases in the atmosphere is often cited — around 10 years for methane and 100’s of years for carbon dioxide, what often gets crucially overlooked is the GWP (Global Warming Potential) for each gas — this refers to the amount of heat that is trapped per unit of methane compared to carbon dioxide over a given time span and this results in methane trapping over 60x more heat than carbon dioxide, so clearly, methane is a potent greenhouse gas.

Greenhouse gases also follow the rules of chemistry, they react with other chemical compounds, in the case of methane, in a chemical reaction it breaks down into water and … carbon dioxide. So this surely means those who argue for a cessation of livestock farming in order to reduce methane have a serious point. Let’s look at the reasons frequently quoted in newspaper articles.

Reasons Frequently Given for Cessation of Livestock Farming

Calls for the reduction or cessation of livestock farming generally include at least a handful of reasons why. We have listed many of these reasons, it should be noted these are taken from multiple articles and, more importantly, not one newspaper article we have read has ever included all the reasons, perhaps the article was intended to be short, or, aimed at a specific audience.

There are some mighty powerful points that indicate cessation of livestock farming is surely necessary. However, as usual where human “needs” and economics are to be found, these are rather “blinkered”. If we now take each of the reasons, remove the blinkers and look at the “bigger picture”, what might that tell us?

1. Ruminant livestock release methane to the atmosphere.

Yes, ruminant livestock release methane to the atmosphere, the average cow will produce as much in eCO₂ per month as a typical, mid-sized family car does travelling 800 kilometres (approx 500 miles) per month. Other “industries” release methane, fossil fuel production (coal mining or oil wells), clearing of forests, landfill sites and … cultivation of crops such as rice, which forms a significant part of the diet for many people around the world.

1. High fuel use for transportation of meat and fertiliser — releases more CO₂ to the atmosphere.

Yes, meat and fertiliser transportation adds eCO₂ to the atmosphere — we would still need fertiliser and transportation for growth of vegetarian food crops.

1. Clearing vegetation/deforestation and converting land for grazing — releases more CO₂ to the atmosphere.

This reason actually covers two crucial points. Firstly, clearing any forested land changes the Earths albedo, the reflectivity of radiation (heat) from the earth surface is greater in cleared land than forested. Secondly, cultivating, ploughing or tilling ground, releases carbon dioxide stored in the earth. This reason is also the one where those in favour of livestock cessation really shoot themselves in the foot:

Clearing of forestry will continue, humans have a need for lumber, for land to build an urban environment on, not just for grazing cows or planting human food crops. Not all the worlds forestry is grown sustainably, so no re-forestation occurs following cutting for lumber in many parts of the world — economics rule again.

Converting forestry into grazing land means the planting of grass for livestock, grass is re-seeded on a cyclical basis, meaning the land is tilled/ploughed and re-sown every 3-5 years. Planting human food crops would certainly mean the land is ploughed once, twice or more a year. Therefore, human food crops would release more carbon dioxide per ploughing over a given time period than grazing land for livestock.

Now to albedo, grassland reflects less heat than that of bare earth, land used for the growth of human crops would, for a period of time annually, be bare.

1. Livestock manure releases methane.

True, but so too does anaerobic bacteria living in swamps or human waste landfill sites.

1. Livestock produce waste in the form of ammonia — a main cause of acid rain.

Yes, livestock produce ammonia, but is ammonia the main cause of acid rain? What about the sulfur dioxides and nitrogen oxides released by industry — it is in fact the case that human industry is the main cause of acid rain – each time you drive your car or burn fossil fuel, you also release these dioxides. Ammonia is also produced naturally by many plants and used as a fertiliser for human food crops.

1. Livestock overgrazing leads to pastures turning to desert.

Yes, true, overgrazing can lead to pasture degradation. There are also other impacts that lead to such degradation, changes in rainfall pattern, encroachment of industry and associated pollution, deforestation for lumber and incorrect irrigation, this can and has happened with crop production for human consumption. Many agricultural crops with repeated tilling, reduce organic matter in the soil so reducing fertility.

1. Water consumption by cows — figures quoted can be as high as 900 litres of water to produce 1 litre of milk.

Probably true, however water consumption would also depend on the feeding regime of the cow. Consider then, the average citizen of the USA uses around 170 litres per day for laundry, showers/baths, flushing toilets, washing cars etc, and around 60% of freshwater is used for human crop irrigation purposes.

1. Watercourse pollution from fertilisers, pesticides and animal antibiotics/hormones could harm human health.

Animal antibiotics/hormone use is heavily regulated or banned in many countries, next time you visit the supermarket and have a choice between home bred meat or much cheaper imported meat — think about why the meat might be cheaper, could it have come from a less well regulated country?. As for pollution of watercourses from fertiliser or pesticides, are crops for human consumption to be grown without use of these, hardly likely.

1. Changing from a methane emitting food source to a vegetarian food source is easier that trying to reduce CO₂ output.

We have already established that some food crops do emit methane (Rice) — so how is it easier, what point is being made here?

1. The cessation of livestock farming can be achieved with relatively little impact, whereas cutting CO₂ industrial output will affect the economy.

Here we have the whole point. Why change our industrial and economic needs for the sake of global warming? In reality, here in the UK, we already grow enough vegetarian crops to feed ourselves – around 50% of the produce is ploughed back into the earth because supermarkets won’t buy it, it isn’t the right size/shape/colour, you the consumer will not want to buy it. It should be noted that ploughing back organic matter also leads to release of greenhouse gases as material breaks down in teh anaerobic environment. How much of a food crop could we grow here, in the Highlands or many other parts of the world, try growing crops at high altitude, on rougher terrain, it is not feasible. If there were no livestock here, what would happen to the landscape, no one to manage it, no livestock to graze it, what exactly would happen to entire species — sheep, cows, deer … and what would the true economic cost be if we failed to feed, clothe and find people work on the land or in associated industries?

As a species, we seem to try to look for any possible solution to problems, provided it has no affect on the way we live our lives. A point to consider, if methane is deemed a worse greenhouse gas than carbon dioxide, consider the real impacts of nitrous oxides – 298x the heat retention (GWP) of carbon dioxide, or CFC11 / CFC12 – 4,750 to 10,900x the heat retention (GWP) of carbon dioxide and ask yourselves are cows farting really the big problem?