10 January 2008

2 minute read

The report shows the damage that all areas of agriculture is causing to the world, but especially highlights that of livestock, examining how livestock emissions alone can vastly bump up the global warming effect and cause our planet to overheat.

GreenPeace claims that when farming ruminant animals, the animals themselves produce the greatest amount of GHGs (up to 60%) through enteric fermentation in the rumen. Other components of the overall GHG emissions contribute roughly similar amounts, with the use of diesel and electricity being at the lower end (Casey and Holden, 2006). Globally, livestock is the most important anthropogenic source of methane emissions (USEPA, 2006a). Methane is a powerful GHG with 20 times the global warming potential of CO2.

The report goes on to say say that there are further considerations to be taken when comparing intensive versus non-intensive livestock production, not least animal welfare issues. Whereas non-intensive systems can be shown to be far more desirable in terms of animal welfare, the position with respect to GHG emissions is less clear. The amount of methane emitted by animals is directly related to the number of animals, so that a more intensive farm will have higher emissions, though the emissions per unit of product (e.g. meat, milk) might be lower (IPCC WGIII Ch.8, 2007). The demand for meat products determines the number of animals that need to be raised. An intensive farm may spare land for other purposes by optimising yield on high quality land and, hence, minimising the area that is used for agriculture (Mooney et al., 2005, Dorrough et al., 2007).

However, it is argued that using less land directly for agriculture will still have an effect on surrounding lands due to high concentrated emissions and different requirements to the infrastructure (Matson and Vitousek, 2006). Furthermore, the length of time it takes to rear an animal has decreased dramatically in intensive farming systems (e.g. from 72 days in 1960 to 48 days in 1995 for broiler chickens). Generally, chickens and pigs use concentrated feed (high protein) more efficiently compared to cattle, which enabled a considerable reduction in the rearing time. As a result, the production of these meats has also increased (Naylor et al., 2005).

Given that the demand of meat has to be met (expecting large, unforeseen global shifts in projected consumption patterns), intensive farming reduces the time necessary to produce the same quantity of product, hence reducing GHG emissions per unit of product. Furthermore, the increase in the production of chickens and pigs may also be favourable considering that these animals produce much less GHG.

Further Reading

- You can view the full report by clicking here.

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