Photo: Eating less meat will reduce Earth's heat

By David Suzuki with contributions from David Suzuki Foundation Senior Editor Ian Hanington.

Will vegans save the world? Reading comments under climate change articles or watching the film Cowspiracy make it seem they’re the only ones who can. Cowspiracy boldly claims veganism is “the only way to sustainably and ethically live on this planet.” But, as with most issues, it’s complicated.

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It’s true, though, that the environment and climate would benefit substantially if more people gave up or at least cut down on meat and animal products, especially in over-consuming Western societies. Animal agriculture produces huge amounts of greenhouse gas emissions, consumes massive volumes of water and causes a lot of pollution.

But getting a handle on the extent of environmental harm, as well as the differences between various agricultural methods and types of livestock, and balancing that with possible benefits of animal consumption and agriculture isn’t simple.

Estimates of how much animal agriculture adds to greenhouse gases range widely, from about 14 to more than 50 per cent of total global emissions. Agriculture exacerbates climate change in a number of ways. Clearing carbon sinks such as forests to grow or raise food can result in net greenhouse gas increases. Farming, especially on an industrial scale, also requires fossil fuel–burning machinery, as does processing and transporting agricultural products.

Determining the overall contribution is complicated by the fact that livestock agriculture accounts for about nine per cent of human-caused CO2 emissions but far greater amounts of other greenhouse gases, which are worse in many ways but less dangerous in others.

According to the UN Food and Agriculture Organization, livestock farming produces 65 per cent of human-related nitrous oxide, which has 296 times the global warming potential as CO2. It also contributes “37 per cent of all human-induced methane (23 times as warming as CO2), which is largely produced by the digestive system of ruminants, and 64 per cent of ammonia, which contributes significantly to acid rain.” But methane stays in the atmosphere for about 12 years, and nitrous oxide for about 114, while CO2 remains for thousands of years.

Emissions also vary by livestock. Pigs and poultry contribute about 10 per cent of global agricultural emissions but provide three times as much meat as cattle — which are responsible for about 40 per cent of emissions — and use less feed. Some plant agriculture also causes global warming. Wetland rice cultivation produces methane and nitrous oxide emissions, the latter because of nitrogen fertilizer use. Different agricultural methods also have varying effects on climate. And some people, such as the Inuit, have adapted to meat-based diets because fresh produce is scarce — and flying it in causes more emissions than hunting and eating game.

The bottom line is that cutting down on or eliminating meat and other animal products from our diets is necessary for protecting humanity from runaway climate change — and from many other environmental consequences, including water scarcity, degraded ecosystems and pollution of waterways and oceans. The FAO reports that global demand for livestock products could increase 70 per cent by 2050 if nothing is done to slow consumption.

Worldwide meat-consumption rates show there’s room to cut down in industrialized countries, where the average person consumed 95.7 kilograms in 2015, compared to the 41.3-kilogram global average, and 31.6 in developing countries. People in South Asia eat less meat than anyone, at about 7.6 kilograms in 2015.

A study by scientists at the U.K.’s Oxford Martin School found global agriculture-related emissions could be cut by a third by 2050 if people followed simple health guidelines on meat consumption, by 63 per cent with widespread adoption of a vegetarian diet and 70 per cent with vegan. The authors found adopting healthier diets with less meat and animal products could also reduce global health-care costs by $1 billion a year by 2050.

Although switching to better agricultural methods and encouraging local consumption could also reduce emissions, those are topics for another column. In the meantime, we can do our part by at least cutting down on meat, especially red meat, or by taking the more significant step of adhering to a vegetarian or vegan diet.

Perhaps the best dietary advice for our own health and the planet’s is from food writer Michael Pollan: “Eat food, not too much, mostly plants.”

May 19, 2016

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Sep 06, 2017
9:23 PM

What if the stats are right, that 60-80% of hospital visits are dietary related?

(ie. Diabetes, Heart Disease, Autoimmune Disorders (ie. MS) etc)

If claims from the McDougall Foundation, and and the TrueNorth Health Center, are true: the top ten killers of man, can be reversed with a plant based diet — would that significantly impact the reasons to leave meat off the plate?

Further, most waste I see in my town, comes from animal based processed foods.

How much toxicity/waste is caused by the health and medicare industries?

How much waste is caused by animal based fast foods?

May 24, 2016
11:18 PM

Oh the thing too with a lot of the UK studies, the most frequently cited research for CO2 emission numbers for food come from the Department for Environment, Food and Rural Affairs [DEFRA] in the UK. DEFRA’s 2009 numbers (referred to in a number of studies of comparative diets) use for CO2 per kg, for beef based solely on all gross CO2 and CO2 equivalent emissions without any subtractions for carbon sequestration, methane oxidation or nitrogen fixing. These are not NET numbers.

DEFRA’s 2009 analysis is based on four scenarios for beef. Obviously the primary driver for their carbon numbers for meats is enteric methane. Thus ruminants (cattle and sheep) on pasture are the worse offenders since they live the longest and emit the most CH4. Consequently “mitigation through intensification” is one strategy thus recommended to reduce GHG emissions with genetically engineered animals that grow faster, require less feed, produce higher yields, live shorter lives and from a GHG perspective, emit the least enteric methane. (Think the cattle equivalent of AquaAdvantage salmon being the ultimate goal). This strategy obviously coincides with what the authors of 2006 Long Shadow also advocated for, and that’s more factory farms (including more CAFO chickens and less pastured “cows”). Most people don’t realize that 2006 Long Shadow’s authors were industrial Ag people.

The bigger problem is you have policy makers and analysts who haven’t been on farms doing the math, Thus they’re coming to overly simplistic solutions without having all the data in hand. The problem with the data available is that more research has been done on the emission side than on the reduction side. The reduction side is also more difficult, expensive and land specific (eg. soils vary). The reduction side doesn’t lend itself to universal pronouncements. Methanotrophs also are unculturable. Regardless researches like Dr. Richard Teague and Dr Jason Rowntree have been doing the research demonstrating the carbon sequestration. There’s even more research in the pipeline coming out in the next couple years measuring methane fluxes in pastures. If you’d like to become better informed on these issues, here’s a site that has copies of a lot of the soil and carbon research done over the past 10 to 15 years. Please check it out

Thank you for your time and attention on these matters.

May 24, 2016
10:58 PM

Please read my review of Cowspiracy as well as my more recent article regarding the World Watch Report numbers which weren’t peer reviewed before publication and have been widely discredited

Here also is some additional analysis I did of the more broadly accepted 2013 Long Shadow report. That report too had issues, namely attributing all land use change to livestock (which isn’t true, just think about palm oil and ethanol)

Finally note, as also detailed in my above analysis, that per the most recent UN Climate Change Conference held in Dec 2014 in Lima, Peru, enteric methane accounted for only 2.17% of GHG emissions in the United States, So blaming rising temperatures on “cows” is something of a red herring. Poor livestock management is an issue, but that’s due to humans not the animals. In well managed systems carbon equivalents are offset by sequestration and methane oxidation as my article on ruminants and methane notes. See:

May 23, 2016
8:24 PM

Again I’ve listen to many of your talks regarding GMO roulette, and have found those talks especially informative particularly regarding DNA encoding to multiple protein expressions and latent expressions. Again really fascinating. But here, you really need more information from varying perspectives including those from the regenerative Ag and HM communities as well as soil scientists like Dr. Christine Jones and Dr. Elaine Ingham. See: In addition to this study another good one for you to read is Paustian et al. 2016 Climate- Smart Soils. Nature — April vol 532.

May 23, 2016
5:38 PM

Here’s another good article (with excellent research sources cited) on ruminants and methane for your edification. I really appreciate your insights on GMO’s but you don’t seem to know that much about soil science,. This isn’t a scholarly source, but the articles referenced are legit.

May 23, 2016
5:34 PM

Here’s a good excerpt from this article: RUMINANTS – A methane pest or climate change solution?

”..The grazing management required for a well aerated soil that supports methanotrophs is consistent with that required for the sequestration of carbon into soils which will further offset any climate change impacts of the methane from ruminants. It’s not only about the balance between the methane producing animals and the methane consuming methanotrophs, it’s about the whole system, which includes the climate influencing effects that carbon can have and the potential for sequestering this in soils via actively photosynthesizing plants under livestock grazing systems…”

To read the full article and cited sources, click here:

May 22, 2016
11:47 PM

This topic and this position is appearing a lot in the media lately. I am disappointed to find it here at the David Suzuki Foundation as I thought you would have a better understanding of the issue. The advice to “eat less meat to solve climate and environmental problems” is a very simplistic solution offered to a very complex problem. I believe that the “do not eat meat to save the planet” advice serves a different agenda altogether and distracts attention from real and viable solutions.

Animal production, in fact agriculture in general, especially badly done, does have a negative impact on the environment, but done properly, it can be a means to solve the problem, as outlined in FAO reports from 2010 ( and 2013 (

Regenerative agriculture, agroecology, and carbon farming to restore soils, grow better food and sequester carbon provide real solutions which are worth promoting. This is not just theory but is already being done globally to effect change surprisingly quickly.

To demonstrate, Gabe Brown in this TED talk, shares his knowledge and experience of regenerative agriculture.

May 22, 2016
6:39 PM

I am an Australian beef cattle grazier. My stock feed on marginal country that is not irrigated or fertilised, and which is otherwise unsuitable for food production. The only water they use is for drinking, and any water they drink, they piss out as fertilizer. The 51% figure you mention has been totally discredited (it is actually closer to 15%) and I am disgusted at you for including it. Classic misinformation. I am all for reducing our meat intake, but NON-FACTORY-FARMED livestock is a key factor in sustainable farming. It is also a way to minimise wildfires, and to convert poor quality marginal country vegetation into high quality food. After all, over 46% of Australia is marginal country and if we left it alone it would result in huge wildfires, particularly as vegetation dries out as temperatures rise and rainfall is less frequent. Over 30% of Australia’s annual emissions are from wildfires, even though they are not included in our official statistics, unlike hazard reduction burns which are included but which release little more carbon than rotting vegetation would. It is well worth reading Simon Fairlie’s book of essays: ‘Meat- a benign extravagance’, which goes into the complicated issue of sustainable meat production extremely thoroughly and with both experience and expertise. As far as methane emissions: ‘New satellite data and surface observations analyzed by Harvard researchers confirm previous data and observations: U.S. methane emissions are considerably higher than the official numbers from the EPA. Significantly, the EPA numbers are mostly based on industry-provided estimates, not actual measurements. While this new study doesn’t attribute a specific source to the remarkable 30 percent increase in U.S. methane emissions from 2002–2014, many other studies have identified the source of those emissions as leakage of methane from the natural gas production and delivery system. The central problem for the climate is that natural gas is mostly methane (CH4), a super-potent greenhouse gas, which traps 86 times as much heat as CO2 over a 20-year period. That’s why many studies find that even a very small leakage rate can have a large climate impact — enough to gut the entire benefit of switching from coal-fired power to gas for a long, long time. Even worse, other studies find — surprise, surprise — natural gas plants don’t replace only high-carbon coal plants. They often replace very low carbon power sources like solar, wind, nuclear, and even energy efficiency. That means even a very low leakage rate wipes out the climate benefit of fracking.’ ( And in the meantime, livestock are scapegoated for increasing methane levels. Easier to blame farmers than mining companies!

May 21, 2016
3:40 PM

Thank you for sharing the information in your article. I am so glad you present science backed data that we can use as a foundation for making better choices for our selves and our planet.

As I was reading the article, however, I was reminded of other aspects of agriculture that I’m sure there was just no space to include but that I would love to see featured in more articles on agriculture. One aspect concerns the healthy integration of food animals into nature. In the ‘Plains’ episode of the PBS documentary series ‘Earth: A New Wild’ they showed, among other things, “how re-introducing species can restore the Great Plains to health … the re-introduction of wolves have inspired Montana ranchers to herd their cattle as if hunted by wolves. They are re-creating the [positive] impact of the once vast herds of bison. Their actions have restored habitat…”

Another aspect is how life health is connected. Grass fed cattle are healthier and increases our health when we eat them as well, according to the data many doctors are now sharing about diet. Quality over quantity would naturally lower the numbers of cattle but increase the health of land and animals (including us).

And then there is the whole concept of permaculture and the vital role animals play in food forests and other permanent, sustainable food systems in both rural and urban settings. Chickens in the city are already here, increasing urban food security, but can you imagine moving around small livestock herds to be used as part of neighbourhood green belt and urban park management? Wild idea, huh.

So, adding these three ideas to what you have already presented, leads me to believe that yes, less beef on the menu is a great start … but different ways of raising cattle and other livestock is something equally important to share and explore.

Thank you for allowing me to share my thoughts on this with you.

May 21, 2016
10:00 AM

The only problem with this view is that it ignores the overwhelming benefits to human physiology with respect to meat consumption. Good, clean meat (organic controls respected) is one of the best foods human can eat. The angle on food for the environmentalist should be focussed on the food processing factories and their contribution to the planets ecological problems as well as the health problems that arise from these products.

May 21, 2016
8:38 AM

While I agree that many rich folks eat too much meat, I wonder if a vegan diet is really the best for health.

East Asians used to be characterized as much smaller than Europeans in stature. This has changed since dairy products became a regular part of their diet. So their height was a result of constraints in diet rather genetics. The Dutch are still the tallest of nations — they have a high dairy and meat diet.

While adults can choose to go vegan, I do not believe evidence supports such a diet as optimal for children. Yes, overall Canadians may eat more meat and dairy than is good for health, but let’s not promote the myth that veganism is the ideal. Humans are omnivores by nature. A Mediterranean diet, which is promoted as healthy, is not vegetarian or vegan.

May 20, 2016
9:54 PM

If the judge of a person is the quality of their children then Mr. Suzuki is a remarkable human all over again. It is from the position of great respect that I frame the following questions:

Is Intensely Biodiverse Food and resource production that enhances natural patterns in nature the most sustainable way to produce energy and amino acids for humans?

Is a high carbohydrate diet responsible for Insulin resistance? Does the oxidization of polyunsaturated fat lead to vascular pathology?

Are Saturated and monounsaturated fats the most nutrient dense forms of energy?

Is it true that The mitochondria of Cancer cells can not use these fats for fuel?

Is it true that using them for fuel allows the mitochondria that supply your heart muscles and our brains to produce ATP 28% more efficiently than they can on glucose, sucrose, lactose, alcohol or glycogen?

Does the quality of the fats from Wild Grazed animal products differ from that of Industrially produced animal products?

Will supporting the wild grazing of animals in Biodiverse environments increase soil quantity and quality while offering the possibility of providing food that does not increase diabetes, heart disease and cancer?

I just sell surfboards so I am not qualified to answer these questions

May 20, 2016
9:29 PM

Great article!

May 20, 2016
8:33 PM

I don’t understand how ammonia contributes to acid rain. Ammonia is a base and should neutralize acids.

May 20, 2016
7:33 AM

Sure, issues are more complicated

May 20, 2016
5:46 AM

In relation to methane and nitrous oxide emissions from wet paddy rice fields, I’m pretty sure I know a natural organic method to stop both these emissions. I have been trialing urban growing systems using a probiotic fertiliser made from minced food waste fermented with modified EM (Effective Microorganisms). The EM contains additional purple non-sulphuric photosynthetic bacteria that utilises infrared light to fix nittogen in anaerobic conditions and carbon in aerobic situations. I use it to inoculate the ‘biowicked’ soil-only wicking beds I build where it replaces the methanogenesis microbiome with this beneficial microbial mix, providing free nitrogen fertiliser and sequestering carbon. As food waste is the main ingredient the probiotic fertiliser can be produced in bulk, and has the added benefit of diverting this food wste from landfill. If poured or sprayed onto paddy fields it should do the same, and instead of producing methane the flooded fields would be fixing atmospheric nitrogen and converting it to plant nutrients. This may be sufficient to replace the nitrogen fertilisers responsible for the nitrous oxide emissions. When the fields are drained between crops the bacteria switches function and would sequest carbon into the soil, improving soil structure and turning the fields into carbon sinks. I have put up some more info at . BTW, I actually met with David in Sydney in 1990 and discussed permaculture and the situation with the Penan/rainforest logging in Borneo.

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