In my previous essay I discussed the unprecedented, raging bushfires we’ve experienced in Australia over the past few months due to climate change combined with the criminal denial and inaction on the part of our political “leaders.” In that essay, I stated: 

Adopting a vegan diet is the single most effective thing we can all do to avert climate change catastrophe, and we ought to be doing this as a priority. Even if the government refuses to act, we can act, now, by going vegan.

Indeed, we don’t need any support from the government to shift to a vegan diet. There’s nothing stopping us from doing it right now. No one needs to consume any animal products in order to be healthy. This is the position of numerous dietetic and health organisations throughout the world. And consuming a vegan diet is cheaper than one which includes animal products.

I concluded by saying that if you are concerned about the bushfire crisis and government inaction on climate change, you’re obliged to adopt a vegan diet (if you haven’t yet done so). Here, I intend to explain the link between animal agriculture and climate change in order to show why it’s so necessary to start eating vegan.

Before I launch into this issue, it’s necessary to point out that veganism isn’t just about a diet. It’s about avoiding all animal products to whatever extent is possible and practicable. This includes clothing, footwear, personal care items and other items of daily use that can easily be omitted in favour of plant-based alternatives. Veganism is a moral imperative and a social justice issue. However, in this essay I’ll  focus only on the role of a vegan diet in preventing the worst effects of climate change. That is, the very minimum we ought to do is to adopt a vegan diet, but in fact we would do well to avoid purchasing animal products (such as leather and wool) entirely, for the sake of the environment as well as for ethics.


From this point onwards I’ll use terms that more accurately describe the gravity of the environmental horror we’re facing worldwide. Instead of “climate change,” which sounds rather mild and unthreatening, my preferred terms are climate “emergency,” “crisis,” “breakdown,” “disaster,” “disruption” and “catastrophe.” “Global heating” is more accurate than “global warming.” This choice of terms reflects the linguistic preference of many climate scientists and others who recognise the dire existential threat posed by the situation.

Finally, in this and other essays I’ll be using words like “livestock” and “poultry” to talk about animals, since these are the terms typically used in discussions involving  agribusiness in relation to the environment. These terms, while obscuring the fact that animals are sentient, non-human persons with wishes, desires and preferences, nevertheless accurately reflect the animals’ status as property, and that they are treated as property, things, or resources, in violation of their fundamental rights.

Unfortunately, many people who care about climate crisis and want to contribute to combatting it are still unaware of the catastrophic impact that meat, dairy and egg production has on global heating and a host of other environmental problems, including loss of fresh water, rainforest destruction, spreading deserts, air and water pollution, acid rain, acidification of oceans, soil erosion, loss of habitat and species extinction. Sure, many people have a vague idea that they should “eat less meat” for the environment. But the role of animal agriculture in climate breakdown tends to be overlooked while almost everyone remains focused on the need to reduce carbon emissions from fossil fuels used for energy by industry and transport—coal, oil and natural gas. The major contribution of animal agriculture to global heating needs to be highlighted. We need to bring it to the forefront of mainstream discussion.

It’s a well-established fact supported by many peer-reviewed studies that animal agriculture, driven by consumption of animal products, is a significant factor in global heating. There is also strong evidence that animal agriculture is the leading cause of the climate emergency.


Studies vary in their estimates of the percentage of greenhouse gases (GHGs) animal agriculture contributes to total GHGs responsible for climate change. The 2006 report Livestock’s Long Shadow  by the United Nations Food and Agriculture Organisation (FAO) found that 18% of annual worldwide GHG emissions are attributable to cattle, buffalo, sheep, goats, camels, horses, pigs, and poultry bred for meat and dairy products. The report states:

The livestock sector is a major stressor on many ecosystems and on the planet as a whole. Globally it is one of the largest sources of greenhouse gases and one of the leading causal factors in the loss of biodiversity, and in developed and emerging countries it is perhaps the leading source of water pollution.

In a later study, Tackling Climate Change Through Livestock (2013) the FAO lowered their estimate to 14.5%. This estimate has now become the most frequently cited in discussions on climate crisis. While 14.5% of total GHGs coming from animal agriculture may not sound like much, it’s still more than the 13% of GHGs that come from all global transport annually—all cars, trucks, trains, planes, ships and tanks—maintaining livestock’s position as one of the world’s primary contributors of human-caused GHGs.

In 2009 Livestock and Climate Change (LCC), an analysis carried out by World Bank environmental assessment experts, Goodland and Anhang, published by US think tank, the Worldwatch Institute, convincingly showed that livestock and their byproducts actually account for at least 51% of annual worldwide GHG emissions. This finding makes animal agriculture the leading cause of climate crisis, greater than all other sources including energy generation and transport.

“If this argument is right” say Goodland and Anhang,

it implies that replacing livestock products with better [plant-based] alternatives would be the best strategy for reversing climate change. In fact, this approach would have far more rapid effects on greenhouse gas emissions and their atmospheric concentrations than actions to replace fossil fuels with renewable energy.

Their call to shift to plant-based foods accords with the views of the chairman of the UN’s Intergovernmental Panel on Climate Change, Dr Rajendra Pachauri, who has described eating less meat as “the most attractive opportunity” for having an immediate impact on climate change. Clearly, given the magnitude of the threat of climate crisis and the havoc it’s already wreaking, eating zero animal products ought to be our goal.

A 2015 study, Neglected Transformational Responses: Implications of Excluding Short Lived Emissions and Near Term Projections in Greenhouse Gas Accounting, found that in Australia, 50% of GHGs were attributable to livestock, supporting LCC’s assessment.

A recent (2019) study, Animal Agriculture is the Leading Cause of Climate Change—A White Paper, concluded that animal agriculture is responsible for a staggering 87% of human-made GHG emissions, revealing the consumption of animal products to be overwhelmingly the major cause of climate emergency.


of these studies demonstrate that animal agriculture is a significant contributor to climate breakdown, supporting the need to cease propping up the animal agriculture industry by adopting a vegan diet. However, the question obviously arises as to why there is such variation in their findings and which estimate is the most accurate. In other words, just how significant is animal agriculture in driving climate breakdown?

There are sound reasons to accept the higher estimates of animal agriculture’s contribution to climate crisis, and that animal agriculture is indeed the leading cause of climate crisis, as shown by three of the studies cited above. This leads to the conclusion that the role of animal agriculture is being consistently sidelined by government, media and by other institutions, including environmental organisations, in relation to its actual importance in driving climate emergency.

The subject of why I think we ought to take seriously the claim that animal agriculture is the number one cause of climate crisis, based on the evidence presented, is one I’ll pursue in a subsequent essay. However, that discussion will benefit from first addressing the ways in which animal agriculture produces GHG emissions.

The burning of fossil fuels is at present the leading source of human-made carbon dioxide (CO2) emissions. However, climate breakdown is caused not just by CO2 emissions but also by other cumulative human-made GHG, aerosol and black carbon emissions.

The principle ways in which animal agriculture produces emissions are through methane produced by livestock, land clearing, prescribed savannah burning for pasture maintenance and emissions from manure.

The production of meat and other animal products contributes significantly to the emission of the three major gases associated with global heating: carbon dioxide (CO2), methane, and nitrous oxide. Consider these facts:

While CO2 is the most abundant GHG, methane is 25 to 100 times more destructive than CO2 and has a Global Warming Potential 86 times that of CO2 in a 20-year time frame. Cows alone produce 150 billion gallons of methane per day. The number one cause of methane emissions is animal agriculture, which contributes 37% of it. Methane causes more global heating than CO2 on an annual basis.

Livestock is responsible for 65% of all human-related emissions of nitrous oxide—a GHG with 396 times the global heating potential of CO2, and which remains in the atmosphere for 150 years.

Even if we were to cease burning fossil fuels, we will exceed our 565 gigatonnes CO2e [CO2 equivalent] limit by 2030, just from raising animals for food.

These super-potent gases—methane and nitrous oxide—issue primarily from farmed animals’ digestive processes, via enteric fermentation, released by belching and flatulence, and from their manure. Methane is the most important of these gases in terms of global heating. The potency of methane as a greenhouse gas is such that the amount of methane produced by just one cow in a year is the CO2 equivalent of burning 1,000 litres of petrol, or driving 12,500 km (7,800 miles).


So it’s not just the quantity but the type and potency of GHGs in terms of their effect on heating the atmosphere, that renders animal agriculture such a critical factor in driving climate breakdown; that makes removing animal products from our diet an essential and potentially extremely effective measure in combatting climate breakdown.

Brook and Swartz explain that cutting methane emissions by reducing consumption of animal products can potentially alleviate climate crisis in a much shorter timeframe than reducing CO2 emissions:

With the livestock industry emitting such a huge amount of methane and given that methane degrades relatively quickly in the atmosphere (in approximately 12 years as compared to hundreds or even thousands for carbon dioxide), a sharp decrease in animal consumption, and therefore subsequent livestock production, would provide the necessary near-term alleviation from global warming potentially spinning out of control.

“Animal consumption” includes eggs and dairy, not just meat.

In other words, the fact that methane cycles out of the atmosphere in a little over a decade, as compared to one hundred to thousands of years before CO2 is fully removed, means cutting out consumption of animal products quickly translates to a cooler planet.

An additional major reason why animal agriculture is so implicated in climate crisis is that, as already mentioned, expansion of animal farming is one of the key factors leading to land-clearing through deforestation, which causes loss of carbon sequestration. Carbon is stored on land in vegetation and soils. When land is cleared for grazing and growing feed crops for animals, carbon is lost from soils as well as trees and other plants, adding to CO2 GHG emissions. The same principle holds for burning of savannahs.

Burning down forests and savannahs to make way for animal grazing and feed crops is also a significant source of black carbon emissions.


I hope this brief overview of the importance of animal agriculture in contributing to climate emergency has been enough to motivate you to start clearing the meat, dairy and eggs out of your fridge and replacing them with healthy, environmentally-friendly plant foods that don’t involve violating the fundamental rights of animals—if you haven’t already done it.

Avoiding animal products is only part of the solution for curbing global heating, even if it is almost certainly the major part. For long term stabilisation of the climate, which will affect younger generations and those to come, it remains essential to drastically reduce CO2 emissions, bringing them down ultimately, and as fast as possible, to zero. At this point of political paralysis there is no alternative but to maintain intense political pressure to that end. However, given the lateness of the hour, the severity of the crisis and the need to make a profound difference in the shorter term in order to avert complete catastrophe, adopting a vegan diet is absolutely mandatory.

If we want to act through mass protest to force the hand of, or remove, unresponsive, criminally negligent governments, we must do it while consuming a vegan diet and advocating the same for society as a whole.

If in addition we want to behave ethically, according to what we need to do to respect the basic rights of nonhuman sentient beings, not discriminating on the morally arbitrary basis of species, we need to go vegan.

By Linda McKenzie

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To learn about how to go vegan:

How Do I Go Vegan?

International Vegan Association

To learn about animal rights:

Abolitionist Approach to Animal Rights