Crunching the climate numbers

Livestock and Climate Instability

The World Health Organisation estimates that in the coming decades climate instability is expected to cause approximately 250 000 additional human deaths per year, from malnutrition, malaria, diarrhoea and heat stress[1]. The consequences of human-induced climate instability are even direr for other species, with estimates that 1 in 6 species will be wiped out by climate change.[2]

The lives and deaths of billions of animals used for human food worldwide are obviously ethically problematic. As well as being the largest cause of human-created suffering they are also one of the major causes of anthropogenic (human-sourced) greenhouse gas (GHG) emissions. The purpose of this article is to clear up the different estimates for Australia and the world of how much livestock is contributing to climate instability and get some clarity on the scale of the problem.

Livestock’s contribution to global GHG emissions

The seminal report on the effect of livestock on the world’s ecosystems came from the United Nations Food and Agriculture Organisation (FAO) report Livestock’s Long Shadow, published in 2006. The report was damning; its executive summary includes one of the most important environmental statements ever made “The livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global”.

Its estimate of Livestock’s contribution to anthropogenic greenhouse gas emissions was 18% of the global total[3]. In comparison, all 35 million commercial aeroplane flights taken annually are about 2%. The report estimated that livestock was responsible for more greenhouse gas emissions than all forms of transport combined, including aeroplanes, trucks, boats, and the world’s 1 billion cars. It stated that livestock was responsible for 34% of anthropogenic methane emissions, a gas which they estimate to be 23 times more powerful as a GHG than carbon, and 64% of all nitrous oxide emissions, which is 293 times more powerful as a GHG than CO2.

The figures in this report have been challenged but have held up pretty well. From one side it was claimed that whilst the report tried to estimate all the lifecycle emissions of animal agriculture, it hadn’t done the same thing for transport. This criticism was taken on board and partly resulted in the 14.5% revised figure in their report Tackling Climate Change through Livestock published in 2013.[4] Whilst the lower figure might have pleased some in the livestock industry, it didn’t alter the scale of the problem, and it remains larger than all forms of transport combined. They also estimated that global meat and dairy consumption would rise 70% by 2050, a year by which many major economies such as the UK and Australia are aiming to have largely decarbonised.

Criticism that the UN report was a massive underestimate came from the World Watch Institute (WWI) in Livestock and Climate Change[5] published in 2009. They stated that the FAO had failed to accurately estimate livestock’s footprint by, amongst other things, not using current measures for calculating the warming potential of methane, ignoring carbon storage if land freed from use for grazing converted back to wilderness and ignoring livestock respiration. Their revised estimate for livestock’s contribution to GHG was an astounding 51%.

There was some open discussion between the authors of the FAO and WWI reports, however, neither side has altered their estimates [6][7].

Worldwide verdict

Minimum of 14.5%

The figure of 14.5% is the most authoritative figure we have, whilst we acknowledge that is likely to be a large underestimation. The figure of 51% is an interesting talking point, but as it focused only on errors in the livestock component of the FAO report, it is not a wholistic report. It would be of great value to have some follow-up work done here.

Livestock’s contribution to Australia’s GHG emissions

Australia’s Sixth National Communication on Climate Change[8] indicates that, due to our reliance on fossil fuels, the fossil energy sector massively dominates our emissions. Agriculture and transport come out roughly equal to the next main sectors dominating our footprint as a nation. It states that agriculture is responsible for 15.2% of our total emissions, and that livestock is responsible for over 70% of our agricultural sector’s emissions. So on the face of it, we have the minimum figure of at least 10% of our national emissions attributable to livestock.

This is in accord with a CSIRO paper in 2011 which also states livestock emissions to be about 10% of our total emissions[9].

It seems like we have a consensus on the figure until we look further into it. The 10% figure doesn’t include the GHG emissions produced from land clearing, despite the government’s own reports clearly showing that “most land cleared in Australia is used for cattle grazing”[10]. It also doesn’t include the carbon storage foregone by the land used for Australia’s largest agricultural industry, beef cattle production.

Whereas the global figures at least attempt to provide a holistic view of animal agriculture, including all the lifecycle emissions involved, we don’t have a similar figure for Australia. In their report Beyond Zero Emissions used the government figures to include land-use changes in the figures for livestock and came up with a total of 15%[11].

With cattle outnumbering people by some margin in Australia, we can confidently say that after our dirty fossil fuel-driven energy system, animal agriculture is the second most significant source of greenhouse gas emissions.

In addition, if methane’s global warming potential was measured on a 20-year timescale, rather than a 100-year timescale (a much more accurate measure due to its shorter half-life in the atmosphere) this would actually put the livestock sector above the stationary energy sector in its emissions intensity.[12]

Australian verdict

15%, likely much higher

Ultimately we don’t have a perfect figure. For a country that is one of the largest per capita greenhouse gas emitters in the world, to not even have a decent figure for our second largest source of anthropogenic emissions says much about Australia’s seriousness in tackling our contribution to climate change.


Though there are many human-created environmental problems, our generation’s issue is that of climate change. Given that, after energy production, livestock is our major source of anthropogenic greenhouse gas emissions, the lack of focus on the sector by either governments or environmental organisations is impossible to understand. What little interest there has been from these sectors has focused on finding scientific solutions to the environmental degradation caused by animal agriculture industries, however, this is problematic for other reasons. It may be the second-largest source of greenhouse gas emissions, but animal agriculture it is, without doubt, the largest source of human-created suffering. A global transition away from animal agriculture would not only be one of the most important victories in our attempts to avoid climate instability for all creatures on the earth but removing them from our food system would also be a major ethical step forward for humanity.

[1] "WHO | Climate change and health." 2004. Accessed 11 Nov. 2015 <>

[2] "One in six of world's species faces extinction due to climate ..." 2015. Accessed 11 Nov. 2015 <>

[3] Steinfeld, Henning et al. Livestock's long shadow. Rome: FAO, 2006.

[4] Gerber, Pierre J et al. Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities.. Food and Agriculture Organization of the United Nations (FAO), 2013.

[5] "Livestock and Climate Change | Worldwatch Institute." 2009. Accessed 12 Nov. 2015 <>

[6] Response to "Livestock and greenhouse gas emissions ..." 2014. 13 Nov. 2015 <>

[7] Herrero, M et al. "Livestock and greenhouse gas emissions: The importance of getting the numbers right." Animal Feed Science and Technology 166 (2011): 779-782.

[9] Henry, Beverley et al. "Livestock production in a changing climate: adaptation and mitigation research in Australia." Crop and Pasture Science 63.3 (2012): 191-202.

[10] "Drivers of land clearing in Australia (PDF - 822.33 KB)." 2014. Accessed 12 Nov. 2015 <>

[11] "Land Use: Agriculture and Forestry - Beyond Zero Emissions." 2013. 16 Nov. 2015 <>

[12]Mahoney, P. “Action on livestock is essential if we are to strike targets” (2015). Accessed 13 Nov 2015 <>