Sorting livestock emission myths from reality

On a regular basis, anti-livestock groups like PETA, Voiceless and Animals Australia publish articles which claim, in effect, that if Australians substituted vegetable foods for the meat, eggs and dairy products they eat, then the nation’s greenhouse emissions would be cut dramatically. A recent example of this type of article was a letter to the editor of the Australian Financial Review by Jason Baker of PETA Australia on 13 May 2014.

Baker pointed out that about 10% of Australian greenhouse emissions are estimated to come from sheep and cattle that are raised for food. This figure was presumably obtained from the national greenhouse inventory published by the Department of Environment. The 2012 inventory estimated, under Kyoto Protocol greenhouse accounting rules, that Australia’s emissions for 2012 were approximately 555 million tonnes of carbon dioxide equivalents, of which livestock emissions were 59 million tonnes, or 10.7%.

There are two fundamental problems with these claims. The first is that the authors obviously don’t understand greenhouse emission accounting rules, and the second is that they have not considered the flow-on effects of the removal of animal-based products from the Australian diet.

On the first issue, it comes as somewhat of a surprise to many people that estimates of greenhouse emissions calculated using Kyoto Protocol accounting rules do not reflect actual emissions added to the atmosphere. This is because the Kyoto Protocol rules are a reflection of international political compromises on which man-made greenhouse emissions will be counted and which will not. As a simple example, Kyoto Protocol rules ignore carbon sequestration occurring in trees that were planted prior to 1 January 1990, even though those trees continue to lock up greenhouse gases from the atmosphere every year.

The Kyoto Protocol emission accounting rules for livestock require that the greenhouse gases produced by sheep and cattle are estimated, but take no account of the greenhouse gases first removed from the atmosphere by the pasture these animals consume. As a result, official livestock emission estimates are effectively gross rather than net emissions.

Using more comprehensive greenhouse accounting systems (for example Life-Cycle Assessment) that estimate net, rather than gross livestock emissions results in a very significant apparent reduction in livestock emission estimates – in fact in some instances the result is halved.

Even ignoring this, a second issue arising from a change to a vegetarian, rather than an omnivorous diet is the flow-on emission implications of that change.

Animal-based foods make up approximately 33% of the calories consumed by Australians, so if they were substituted with plant foods Australians would increase consumption of plant-based foods by approximately 50% (because animal-derived foods have a higher nutrient and energy density than plant-based foods). This would mean that either the area of land in Australia sown to crops would need to expand (resulting in more greenhouse emissions from tree clearing, land cultivation and fertiliser use) or more plant-based foods would need to be imported into Australia from other countries, many of which have less greenhouse emission efficient production systems.

Each of these would result in additional greenhouse emissions, which would need to be factored into any calculations about the presumed greenhouse benefits of the dietary change.

There is also the question of what would happen to the land currently devoted to livestock grazing in Australia – much of which is unsuitable for cropping. Presumably, in the absence of sheep and cattle, a mix of kangaroos, and feral camels, goats and buffaloes would become the main grazing livestock. Despite goats, camels and buffaloes all being emission-producing ruminants like sheep and cattle, under Kyoto Protocol accounting rules emissions from these sources are not counted. So although official emission statistics might show a reduction in livestock emissions, the actual livestock-derived greenhouse emissions released into the atmosphere might change very little.

Even if domestic livestock were not replaced by feral animals, the unutilised pasture would result in more bushfires, producing greenhouse emissions. Kyoto Protocol emission rules currently only count these if the fire was man-made, and only count the emissions associated with the methane and nitrous oxide released into the atmosphere by the fire, and not the carbon dioxide. While the ‘official’ emission estimates might appear lower, the actual emissions released to the atmosphere would be significantly higher than this estimate.

The greenhouse emission benefits anti-livestock activists claim to be associated with vegetarian diets are highly speculative, and grossly overstated. If their real concern is global warming, they should focus on coal-fired electricity and vehicle fuel use which make up three-quarters of Australia’s greenhouse emissions.

Back to August 2014 Insights contents page.

Images: Clare Bellfield, Dairy Australia, Mick Keogh