How Sustainable Is Livestock As A Food Source?

In the third post in my series on the environmental impacts of agriculture, I am looking into livestock and how the rearing of animals for food is putting pressure on many resources while contributing to our greenhouse gas emissions.

Aside from the vegetarians in society, most of us (me included) probably enjoy eating some form of meat at least a couple of times a week but just what impact does this carnivorous side to human diets have on the environment and would we all be better off eating less meat? These are the questions I hope to answer and they are ones which everyone should pay attention to if they wish to reduce their carbon footprint.

The Economic Balance

You may assume that an industry as global and as massive as the livestock industry would be a major contributor to world GDP but it turns out not to be the case. In spite of the large environmental impacts that I’ll mention, rearing livestock accounts for just 1.5% of global GDP.

On the other hand, according to a joint report by the FAO (UN’s Food and Agricultural Orginzation) and ILO (International Labour Organization), approximately 1 billion people are employed in the whole of agriculture (another report entitled “Livestock’s Long Shadow” (LLS) by the FAO puts the number of people employed by livestock alone at 1.3 billion but this whole report has been shown to be less accurate so I prefer to take the first number). This is often because arid landscapes don’t leave many other options for making a livelihood and so livestock becomes the default.

Such information seems counterintuitive; how can an industry employ such a vast number of people and yet only generate a tiny fraction of wealth? I would hazard a guess that many people who raise livestock do so for their own nutritional benefit rather than to sell and thus do not contribute to measurable GDP. Indeed many will raise livestock for milk more than meat.

The Atmospheric Damage

While there are good reasons for many people to be involved in the rearing of animals such as cattle, sheep and pigs, there is no doubting the disproportionate amount of greenhouse gas emissions generated.

The most comprehensive and perhaps most accurate report on the emissions caused by the livestock industry is entitled Livestock and Climate Change and the figure they have calculated is roughly 51% – that’s more than half of all man-made greenhouse gas emissions coming from the livestock industry. Livestock’s Long Shadow put this figure at just 18% but the authors have since conceded that the 51% figure is far more representative of the truth.

Here in the UK, just the methane and nitrous oxide from agriculture create a combined 9% of total greenhouse gas emissions with much of it coming from the rearing and feeding of livestock.

These gases have a much greater warming effect on the environment than CO₂ with methane having as much as 23 times the warming potential and nitrous oxide having 296 times the potential (LLS). This means that significant increases in livestock production will have a disproportionately large impact on global emissions.

There are even some scientists who claim that we are underestimating the impact of methane on the environment because, as a reactive element, it can combine with other gases and this may result in twice the warming potential we currently assume.

The total emissions figure for livestock also includes those which come from deforestation and in the Amazon alone between 1996 and 2005, an average annual emissions total of 716MtCO₂ was due to the cutting down of rainforest.

All in all, I’d say that the livestock sector has quite some impact on our environment…and it doesn’t stop at greenhouse gases, it is taking over what little land we have.

Livestock and Land

By far and away the biggest anthropogenic user of land is the livestock industry and I find the figures quite astounding; 26% of the world’s ice-free terrestrial surface is used for grazing and one third of all arable land is used to grow feed for the livestock (LLS).

Over the years the increased demand for pasture has, according to the Brazilian government, meant that 80% of the deforested land in the Amazon is now used for grazing and much of the rest is used to grow feed crops.

Deforestation in the Amazon is slowing and the rate is at its lowest since satellite monitoring began in 1988 but at 2408 square miles between August 2010 and June 2011, a significant area is still disappearing each year.

The problem of grazing animals is not only the amount of space they require but also the degradation of the soil that occurs. Thanks to overgrazing, compaction and erosion, around 20% of the world’s rangelands suffer from some level of degradation and this is as much as 73% in drier areas (LLS).

Soil degradation can be even more extreme in some parts of the world with areas literally turning to desert after herds of grazing animals consume the protective vegetative layer which then leaves the soil at the mercy of the wind and rain. Nigeria, Iran and Afghanistan have all seen great swathes of new desert being formed in recent decades while China may well be suffering the most with as many as 24,000 villages in northern and western China having been fully or partially abandoned because of drifting sand in the past 50 years.

Growing crops to feed livestock can do just as much damage as the grazing itself, especially in regions where natural grasslands are not naturally capable of supporting cultivated crops. There are at least two major examples of this in the “Dust Bowl” of 1930s America and in the Soviet Union during the 1950s. Parts of the former Soviet state of Kazakhstan now have a wheat yield of one sixth what it is in France while much of the land lays abandoned because it is no longer fit to grow anything on.

Other Effects of Rearing Livestock

Fertilizer & Pesticides

Even on areas where desertification does not occur, the trampling of ground by grazing animals can make it harder for root systems to take hold and for water to be absorbed and this means that fertilizer is more commonly required should that land be used for planting crops.

Furthermore, in the US it is thought that the livestock industry is responsible for 37% of pesticide use thanks to the feed crops that are required to supplement the animals’ diets. As I have previously discussed, there are many flaws in fertiliser use and problems associated with pesticides so any exacerbation of their use because of livestock is another downside of eating so much meat.

What is worse is that the manure produced by grazing animals is rarely used directly to fertilise feed crops in the same location. Crops are most often grown separately to the livestock herds and so not only is fertiliser transported to crops, those same crops have to then be hauled to where the animals are kept. It’s a wholly inefficient system in my opinion.

Water

Around 8% of human water use is due to the livestock industry, once again in the cultivating of those darned feed crops, and as I have recently commented, there is a scarcity for water in many parts of the world including the UK.

Biodiversity

According to the WWF some 306 out of 825 terrestrial ecoregions are under threat from livestock and its expansion. This threat to biodiversity is not a recent phenomena; indeed deforestation has its roots so deeply in the livestock industry that many claim it to be the biggest driver in the reduction of biodiversity during human history. Today it is thought that 20% of all the animal biomass on the planet is comprised of livestock.

The Livestock Paradox

It is strange to think that by rearing fewer head of livestock you might actually have more food to eat but while 77 million tonnes of dietary protein is consumed by livestock each year, only 58 million tonnes is produced from the animals after slaughter.

As is argued here though, it is not sensible to presume that if we did not raise those animals that all that additional food would become available – much would probably not be grown in the first place. Besides, animal protein is better for humans than plant protein.

On a more local level, however, it is sometimes to the detriment of society to feed crops to animals rather than use it for human consumption. In Mexico, for example, the allocation of grain given to livestock rose from 5% in 1960 to around 30% at the present time regardless of the country’s 22% malnourishment rate.

What are the Trends?

Meat consumption per person is usually much higher in western society and in the middle classes so as incomes rise in developing countries, the demand for meat is likely to skyrocket.

This poses the question as to whether the planet can continue to support the livestock demanded by the human population. Pasture availability will be one major pressure the industry faces and without further destruction of forested areas it is hard to see where such land is to be found.

Furthermore, the increase in greenhouse gas emissions that would result from an expanding livestock sector are unsustainable and certainly don’t match the suggested limits to emission growth required to prevent catastrophic climate change.

So we will have to find a way of becoming more efficient in our rearing of livestock in order for demand to be met.

I’ll talk a bit more about such efficiency and other solutions to the problems I’ve put down here in a future post where I’ll also talk about various efforts to tackle issues arising from monocropping, pesticides and fertilisers.

On the whole it is probably better for the environment to eat less meat, red meat in particular and have some meals without any meat whatsoever. This will contribute to a lower personal carbon footprint, not to mention the money you can save by substituting meat for vegetables, beans and other alternatives.

Watch out for the final post in this series or follow me on Facebook or Twitter to get instant notification of when it is available to read.

Steve (156 Posts)

I am chief writer and editor on Green Steve. Blogging since 2011, I like to delve into a wide number of topics to help people reduce their carbon footprint. You should follow me on Twitter here. And add me to your Google+ circles here.

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