According to the United Nations Food and Agriculture Organization, farmed animals contribute 14.5 per cent of human-generated greenhouse gas emissions, which is more than every car, plane, truck and train on the planet.
This is because at every stage – from acquiring land for grazing to plastic-wrapping the final product – the production of meat, milk and eggs is energy intensive.
And because animal farming is so inefficient (we get back far fewer calories than we feed to the animals), a LOT of land is needed to grow their feed. This has led to forests and other habitats being destroyed, which not only releases even more climate-changing gases, it means there are fewer trees on the planet to absorb the CO2.
But there’s more…
Animals themselves exacerbate the problem. They release methane – a gas that has a warming effect 86 times more potent than carbon dioxide (over a 20-year timeframe).
Farmed animals produce such large amounts through their digestive process and manure, that animal agriculture is considered one of two leading emitters of methane gas worldwide. The other is the production of fossil fuels.
In addition to CO2 and methane, animal agriculture is also responsible for nitrous oxide emissions. This gas – which is released when the animals’ waste is broken down – is 300 times more potent than carbon dioxide in terms of its potential to intensify global warming.
1 Food and Agriculture Organization of the United Nations, ‘Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities’, 2013 http://www.fao.org/3/a-i3437e.pdf [Accessed 1 December 2018]
2 Gayathri Vaidyanathan, ‘How bad of a greenhouse gas is methane?’ Scientific American, 22 Dec 2015 https://www.scientificamerican.com/article/how-bad-of-a-greenhouse-gas-is-methane/ [Accessed 1 December 2018]
3 ‘Methane emissions from cattle are 11% higher than estimated’, The Guardian, 29 Sept 2017 https://www.theguardian.com/environment/2017/sep/29/methane-emissions-cattle-11-percent-higher-than-estimated [Accessed 1 December 2018]
4 Damian Carrington, ‘Oceans suffocating as huge dead zones quadruple since 1950, scientists warn’, The Guardian, 4 Jan 2018 https://www.theguardian.com/environment/2018/jan/04/oceans-suffocating-dead-zones-oxygen-starved [Accessed 1 December 2018]
5 Damian Carrington, ‘Huge reduction in meat-eating “essential” to avoid climate breakdown’, The Guardian, 10 Oct 2018 https://www.theguardian.com/environment/2018/oct/10/huge-reduction-in-meat-eating-essential-to-avoid-climate-breakdown [Accessed 1 December 2018]
6 Jeff McMahon, ‘The four most effective things you can do about climate change, according to science’, Forbes, 13 Jul 2017 https://www.forbes.com/sites/jeffmcmahon/2017/07/13/the-four-most-effective-things-you-can-do-about-climate-change-according-to-science/#2ccf97f1635c [Accessed 1 December 2018]