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Is being a vegan more environmentally friendly than otherwise?

Would it be sufficient for people to stop eating meat to stop global warming? I've heard that the process to bring meat to everyone's plate is one of the biggest contributors to greenhouse emissions.

This include the feeding of the animals, the cooling of the meat, transport, etc.

marked as duplicate by Larian LeQuella Oct 23 '12 at 5:11

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  • You mean because cows produce a lot of CO2? You really should expand your question. – Martin Scharrer Mar 29 '11 at 10:04
  • Yes I'ld expand indeed. I will. Or yeah, maybe I'm out of topic. – Pierre Watelet Mar 29 '11 at 10:43
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    I still wonder what's the percentage of human population that eats meat every day. – Pierre Watelet Oct 28 '11 at 10:11
  • Even reducing emissions to zero will not stop global warming. Only geoengineering can. – vartec Oct 22 '12 at 10:01
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    Seems like this is fundamentally the wrong question: is it the eating of meat that impacts AGW (assuming those impacts for the sake of discussion), or is it industrial agriculture? For instance, if I take my bow, kill a rabbit or deer, and cook it over a fire using dead wood (which would otherwise rot or be burned in a wildfire), have I affected the world's CO2 balance at all? Conversely, if I eat fruits & vegetables trucked across the country, or flown in from Chile, isn't my vegan diet having a large CO2 impact? – jamesqf Jan 8 '17 at 5:55
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The meat industry is indeed a major contributor to global warming, and other environmental effects such as deforestation.

However, it does not seem that stopping eating meat by itself is enough to stop global warming.

In Diet, Energy, and Global Warming by Gidon Eshel and Pamela A. Martin, the authors claim that moving from meat-based diet to a vegetarian diet saves about 6% of the greenhouse gas emissions:

Conclusions

We examine the greenhouse gas emissions associated with plant- and animal-based diets, considering both direct and indirect emissions (i.e., CO2 emissions due to fossil fuel combustion, and methane and nitrous oxide CO2-equivalent emissions due to animal-based food production). We conclude that a person consuming a mixed diet with the mean American caloric content and composition causes the emissions of 1485 kg CO2-equivalent above the emissions associated with consuming the same number of calories, but from plant sources. Far from trivial, nationally this difference amounts to over 6% of the total U.S. greenhouse gas emissions. We conclude by briefly addressing the public health safety of plant-based diets, and find no evidence for adverse effects.

Note that this study is based on US data - the effect would be smaller in places where current diet already includes less meat.

I don't know what level of CO2 emission reduction is needed to stop global warming. but the change of green house gas concentration between the beginning of the industrial revolution and today is about 40% (data from US Department of Energy) - much more than what will be saved from stopping the meat industry. This is a lot, but it doesn't appear enough.

Based on Target atmospheric CO2: Where should humanity aim? A level of 350 PPM of CO2 is desired to stop global warming, while the current level is 385 PPM - a difference of about 8%.

This is much closer to the amount reached by the Diet, Energy, and Global Warming paper, but a similar study that takes into account global (and not just US) data is needed to get a real conclusion.

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    The consensus is that we would need to reduce GHG emissions by at least 25 to 40% below 1990, and some environmentalists think this is too low. Feel free to edit your answer to add this. – Borror0 Mar 29 '11 at 11:32
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    Could you add a source for the claim that the change of green house gas concentration between the beginning of the industrial revolution and to day is about 40%? Also, can you provide non-political references? Peer-reviewed scientific sources are preferred. – oosterwal Mar 29 '11 at 12:59
  • @oosterwal I added the relevant reference, and replaced the reference regarding target CO2 levels to the original paper – Ophir Yoktan Mar 29 '11 at 13:16
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    Be careful: a 6% of reduction in CO2 emissions is not comparable to a desired 8% reduction of CO2 concentration in the atmosphere. – Evargalo Apr 4 '18 at 11:20
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Yes, it would be a major contribution! (but it would not be sufficient)

The Union of Concerned Scientists wrote a report called Solutions for deforestation-free meat. The report is mostly about inefficiencies of existing food production; e.g. only 20% of the worlds agricultural land is used for crops for direct human consumption, and 80% of the agricultural land is for pastures or cropland for livestock feed. The report also mentions that The effects of tropical deforestation (...) are responsible for about 15% of the world's heat-trapping emissions.

The study cites Stehfest et. al (2009). Stehfest et. al (2009) report that the livestock sector accounts for 18% of greenhouse gas emissions, and that A global transition to a low meat-diet (...) would reduce the mitigation costs to achieve a 450 ppm CO₂-eq. stabilisation target by about 50% in 2050. The article explains the details, but it is due to the reversal of deforestation that a vegetarian (and certainly a vegan) diet would imply. This is 65–75% of the total cumulative emission reduction. Of course, there are some details to be considered, but certainly, a meat-free diet would be a significant contribution to reduce global warming.

  • Boucher, D., P. Elias., L. Goodman, C. May-Tobin, K. Mulik, S. Roquemore: Solutions for deforestation-free meat. Union of Concerned Scientists.
  • Stehfest, E., L. Bouwman, D.P. van Vuuren, M.G.J. den Elzen, and P. Ka- bat. 2009. Climate benefits of changing diet. Climatic Change 95:83–102.
  • Why the downvote? – gerrit Dec 18 '12 at 19:11
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    Good answer. Sadly, some members downvote because they don't like how the answer looks. – George Chalhoub May 11 '15 at 11:37

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