Rethinking Animal Agriculture: The Environmental Imperative for Plant-Based Diet

The last IPCC report (2022) demonstrates that current food systems are responsible for 20% of global greenhouse gas emissions. Therefore, transitioning to a more sustainable food system is an immediate need. In 2006, a UN report declared that the livestock sector is one of the top two or three most significant contributors to environmental problems and should be an essential policy focus. Nevertheless, there is controversy around its relationship to total greenhouse gas emissions. In 2006, the FAO of the United Nations released “Livestock's Long Shadow”. In that report, it is identified that 18% of anthropogenic greenhouse gas emissions are caused by animal agriculture. Their methodology is criticised by Goodland and Anhang (2009), who declared the ratio as 51%. Anghan and Goodland (2009) demonstrated the livestock sector's uncounted, overlooked, and misallocated GHG emissions. In 2010, another UN report stated that a global shift towards a plant-based diet is vital to save the Earth from biodiversity loss, land degradation, water shortages, air pollution, water pollution, and climate change (Carus, 2010).

Rao (2021) provided the findings of a Global Sensitivity Analysis (GSA) and demonstrated that animal agriculture is the primary source of climate change, accounting for 87% of greenhouse gas emissions. Goodland and Anhang (2009) also declared that a considerable reduction in livestock can cut GHG emissions more quickly than renewable energy and energy efficiency initiatives. Cheng, McCarl, and Fei`s (2022) broad literature review shows that livestock is a climate change driver, accounting for 14.5% of total anthropogenic GHG emissions. It showed that one of the main problems is enteric fermentation. Enteric fermentation is generated mainly in the digestive systems of ruminants, where bacteria break down rough plant components and create methane (Cheng, McCarl, Fei, 2022). Since methane has more potential than other GHGs to warm the planet, FAO suggests that to reach the goal of limiting global warming by 2030, countries need to cut methane emissions produced by livestock by 30% (FAO, n.d.). The Special Report of the IPCC on Climate Change and Land (2019) analyses the mitigation potential of shifting diets on the demand side by 2050. Vegan, vegetarian, flexitarian, healthy diet, fair and frugal, pescatarian, climate carnivore, and Mediterranean are the clusters of diets that are reviewed, based on a wide range of literature. All data is obtained from a wide range of literature.

Adopted from the Special Report of the IPCC on Climate Change and Land (2019)

As the table demonstrates, a vegan diet has the highest potential for mitigation. The systematic review of Nelson et al. (2016) and IPCC (2019) also confirms that animal-based foods were linked to a greater estimated environmental impact, while plant-based foods were linked to a lower estimated environmental impact. In that report, the IPCC particularly mentioned the research of Springmann et al. (2016) and Stehfest et al. (2009). According to this, in the most extreme case, where there is an entirely plant-based diet, sufficient food production in 2050 might be accomplished on less land than is now used. This would allow for notable forest regeneration and reduce land-based GHG emissions (Stehfest et al., 2009, as cited in Mbow et al., 2019).

Consequently, GHG emissions are not the only problem created by animal agriculture. Deforestation, manure management, land and water footprints, and biodiversity loss are some issues triggered by the livestock sector. For instance, animal products account for 85% of the UK's total land footprint, even though they supply only 48% of the total protein and 32% of the total calories (de Ruiter et al., 2017). Consumption of animal products accounts for more than a quarter of humanity's water footprint (Hoekstra, 2012). Deforestation is a well-known example as it relates to animal agriculture. According to Ritchie (2022), 72% of deforestation in Brazil is driven by cattle ranching. In addition, the economic benefits of switching to plant-based diets have been examined, and it has been demonstrated that this can save money on healthcare, unpaid informal employment, and lost work days (Springmann et al., 2016). Such examples can be found throughout the literature and provide the context in which veganism became an ecological movement.