What if the whole world went vegan?

If every person on Earth adopted a vegan diet – without milk, meat, honey, or any other animal-sourced foods – the greenhouse gas emissions associated with the food system in 2050 would fall by more than half compared to 2005/2007 levels. That’s one of several striking findings from an analysis of food and climate published yesterday in the Proceedings of the National Academy of Sciences.

The food we eat is responsible for over one-quarter of global greenhouse gas emissions. Of those, 80 percent are linked to livestock production. Eating too much red meat and not enough fruits and vegetables are also linked to health problems such as cardiovascular disease and cancer.

Previous research has suggested that healthy diets could have environmental benefits and has explored ways to encourage such dietary shifts. But the new study is the first to quantify the health, environmental, and economic benefits of dietary changes all at the same time.

To do this, researchers from the University of Oxford in the UK combed through reams of data from the UN Food and Agriculture Association, the World Health Organization, and previous epidemiological and life-cycle analysis studies to compare the effects of various approaches to eating.

If current dietary habits and trends continue, the greenhouse gas emissions associated with the food system in 2050 will be 51 percent higher than current levels. This is due to factors including global population growth and the fact that as populations get wealthier they tend to start eating more meat.

But if everyone in the world followed international dietary guidelines for healthy eating, 2050 emissions from the food system would be held to just 7 percent over current levels, the researchers calculated. This is because, as a species, we would consume less greenhouse-gas-intensive red meat and more low-greenhouse-gas fruits and vegetables, as well as fewer calories overall.

Similarly, the researchers calculated that if everyone ate a vegetarian diet, consuming eggs and dairy but no meat, emissions would fall by 44 percent; emissions would decrease by 55 percent if everyone became vegan.

Those emissions savings would be worth $234 billion US per year in the healthy diet scenario, $511 billion for the vegetarian diet, and $570 billion for the vegan diet.

The savings in health costs from these dietary changes are even greater: $735 billion US per year in the case of the healthy diet, $973 billion for the vegetarian diet, and just over $1 trillion for the vegan diet.

These savings come from lower rates of coronary heart disease, stroke, type 2 diabetes, and cancer. In turn, those health improvements would result in 5.1 million fewer deaths per year worldwide in the healthy diet, 7.3 million in the vegetarian, and 8.1 million in the vegan scenarios.

The health, environmental, and economic benefits of all three of these dietary scenarios seem impressive on their face. But the task of reducing global greenhouse gas emissions enough to limit warming to 2 degrees Celsius in global average temperature – considered by many scientists a tipping point for climate disaster – is a truly massive one. Only the vegan diet scenario, in which the entire world’s population eschews animal foods altogether, puts the planet on track to accomplish this.

To be clear: a global vegan diet wouldn’t hold the planet below the 2-degree threshold on its own, it would merely enable the food system to make its proportional contribution to this task. This means that if we want to keep eating animal products, we’ll have to find extra emissions savings elsewhere.

And any of these alternative diets would involve huge shifts in the global food system. In the healthy global diet scenario, the world’s agricultural system would need to produce 25 percent more fruit and vegetables, and 56 percent less red meat, than it does today. The vegetarian and vegan scenarios would require even bigger shifts in production.

Still, it’s worth considering eating more lentils. The researchers calculated that three-quarters of the environmental and health benefits from changing diets would occur in developing countries. But developed countries would gain most per capita. So particularly for people who live in wealthier countries, changing one’s diet could be a meaningful climate action indeed. – Sarah DeWeerdt | 22 March 2016

Source: Springmann M. et al. “Analysis and valuation of the health and climate change cobenefits of dietary change.” Proceedings of the National Academy of Sciences USA DOI: 10.1073/pnas.1523119113

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20 Comments

  • JC March 22, 2016 at 9:23 am

    “As environmental science has advanced, it has become apparent that the human appetite for animal flesh is a driving force behind virtually every major category of environmental damage now threatening the human future: deforestation, erosion, fresh water scarcity, air and water pollution, climate change, biodiversity loss, social injustice, the destabilization of communities, and the spread of disease.” Worldwatch Institute, “Is Meat Sustainable?”

    “If every American skipped one meal of chicken per week and substituted vegetables and grains… the carbon dioxide savings would be the same as taking more than half a million cars off of U.S. roads.” Environmental Defense Fund

    “A 1% reduction in world-wide meat intake has the same benefit as a three trillion-dollar investment in solar energy.” ~ Chris Mentzel, CEO of Clean Energy

    There is one single industry destroying the planet more than any other. But no one wants to talk about it… http://cowspiracy.com

    Reply

  • Mary Finelli March 23, 2016 at 1:14 pm

    Being vegan is easier, better, and more compelling than ever. It’s the best thing we can do for our health and to protect animals and the environment. It’s also a delicious way to eat! There are marvelous vegan versions of virtually every type of food imaginable.

    Reply

  • Walter Neser March 24, 2016 at 11:05 am

    What this and other studies of this sort fails to take into account is, that before the human population explosion wiped out the worlds populations of Buffalo, Bison and other farting burping ungulates etc, There were more of them farting and burping on the planet than there are cows right now or will be in 20 years time, so, this is BS! Humans cause climate change, if you want to solve it, don’t change your diet, change your reproductive habits and DON’T breed! That is all.

    Reply

  • Nancy Pl March 28, 2016 at 11:23 am

    Before commenting on this article, people need to carefully read it and consider what it’s saying. There are numerous studies and world-renowned scientists that understand the devastating impact animal agriculture has on our planet.
    There are millions of cows, pigs, and chickens in the U.S. alone being bred for food, 95-99% on factory farms, the only way to meet demand-supply for millions of people.
    A most vital solution to climate change and the rising proliferation of chronic illnesses: vegan lifestyle. Sounds extreme at first, for sure, as it did to me about two years ago. Now living vegan has become the most natural, ecological-friendly, and compassionate choice. With all the plant-based nutrition options, it’s never been easier and more delicious.
    You can hide from the truth but that won’t make it go away!

    Reply

    • Adam Z November 25, 2016 at 4:07 am

      Okay say we as a world stop eating meat, what happens to all the cows that are alive right now? Just because we eat them doesn’t mean they disappear or are we going to kill them all? Have one last carnivoristic party?

      Reply

      • Rox W November 27, 2016 at 10:18 pm

        People will become vegan gradually, meaning industry supplies (cows) will decline gradually too. Remaining cattle will likely be taken care of by animal sanctuaries, especially if the whole world is vegan, there’s bound to be enough money for a safe place to keep leftover farm animals for the duration of their life (or to preserve their species).

  • Nancy Pl March 28, 2016 at 11:25 am

    AND the oceans are dying.
    (18 min.) “Legendary ocean researcher Sylvia Earle, PhD, shares astonishing images of the ocean — and shocking stats about its rapid decline.” Dr. Earle is called “Her Deepness” by the New Yorker and the New York Times, a “Living Legend” by the Library of Congress, and first “Hero for the Planet” by Time magazine.
    Watch this 18 min. video: https://youtu.be/43DuLcBFxoY

    Dr. Sylvia Earle is vegan. She is called “Her Deepness” by the New Yorker and the New York Times, a “Living Legend” by the Library of Congress, and first “Hero for the Planet” by Time. She is an explorer, lecturer, author, and oceanographer.
    Watch this (4:50 min.) – https://youtu.be/cOU_7emfPAo

    Reply

  • Pearl April 5, 2016 at 4:00 pm

    I’ve been vegan for years, and gluten-free. I agree that factory farming has a big impact on the environment. It sounds like a very logical and solid solution to the climate issue. It’s actually quite easy for upper-middle class Americans when we can afford the alternatives. I buy Whole foods, organic foods and I take time to cook everything from scratch. Lentil soups, gluten-free breads, kale smoothies. I had my own organic garden on my own land. But what about the working poor? What about people who can only afford a $3 meal at McDonalds?

    As the cost of red meat is increasing, the theft of meat is also increasing. It’s very hard to change the minds of people who desire meat. If pressure is applied to such giants as McDonalds, they can wean people off of meat. It’s supply and demand. There needs to be a shift in the way things are operating. Not many people can become homesteaders, growing their own food, raising their own livestock. This would be an amazing alternative for people to become more self-sufficient. Our society is an industrialized one. Meat is “factory farmed”. So the problem not only lies in people wanting to eat meat. It’s a problem with the system of corporations taking over and industrializing everything at the expense of our health and the Earth’s health.

    We need a new system. That revolution can start with us. But it ultimately relies on the government creating regulations, solutions and not rewarding corporations.

    Reply

  • Jonatan Yair April 8, 2016 at 7:25 am

    There are still people that think that climate changes are just stories, is sad to see those reactions in some of my family members.
    I like this article, It is possible to translate it to Spanish and share it on my blog?

    Reply

  • Anonymouse June 24, 2016 at 8:21 am

    Oh my God! The whole world turning vegetarians would be a nightmare. Humans were not meant to jusy eat plants and vegetables, meat is part of our diet.

    Reply

  • Allison Baker August 21, 2016 at 11:14 am

    It’s considerable but saying your ‘saving the animals’ isn’t entirely true because pesticides used to protect various crop do tend to affect the insects and saying insects and smaller scale creatures like worms in the soil etc of the animal kingdom aren’t animals, then you’re reasoning is messed up.
    A balanced diet is better.
    Yes whole food diets do have their positive impacts but outside America, meat is apart of people’s cultures whether its for money or keeping warm in colder months and trying to change an aspect of one’s culture, changes an entire cycle of life.
    In conclusion. It’s not what you eat. Or how you eat it. Everything can have a negative impact on the surroundings because of how you put it out there and how you emotionally, physically and mentally go on about it.

    Reply

    • Allison Baker August 21, 2016 at 11:16 am

      You never will realize it until it actually starts going down hill and videos start popping up preaching the opposite.
      We all indirectly hurt or abuse something so no one is really guilt free.

      Reply

    • Kiyara November 11, 2016 at 10:25 pm

      They are not saving every single animal, but its about reducing the suffering as much as possible. Its true we cannot stop everything. But being a vegan will reduce the suffering, abuse, caused by humans to a massive extent. Not being able to save everyone doesnt mean you should kill more. And eating meat in your diet, requires feeding the livestock. And that requires way more plants than it does when taken directly. In other words a vegan diet saves both animals and plants to a massive extent. And so it’ll also benefit the insects you were concerned about.

      ” a balanced diet is better”. What sientific proof did you base this statement on. If being a vegan is unhealthy compared to a diet consisting of meat then how is it that an average vegan lives longer than a meat eater. They have also prooved meat eaters to have a higher risk of heart problems and cancer compared to those on a plant based diet. Im not saying meat eaters definitely die of these things. But vegans have a 62% reduced chance of heart dieseases. Also there are vegan athletes and body builders that are perfectly healthy and are great sports.

      And saying something is a part of culture is not a justification for crime. There are cultures where kids are forced to get married. But it is still wrong. The thing is if we can get into a diet that makes us healthy, and doesnt support animals being locked up, abused, raped, mutilated, and finally an escape from all the hell, getting slaughtered, thats the right thing to do. There is no justification for making a profit out of slavery, and murder. We do not have the right to take their freedom away especially when we can live a healthy lifestyle on a vegan diet.

      “It’s not what you eat. Or how you eat it. Everything can have a negative impact on the surroundings because of how you put it out there and how you emotionally, physically and mentally go on about it.”
      Im not gonna spend a lot of time on this, but just ask yourself if you would say the samething to jeffrey dhamer. If not why, when animals too value their lives just as much as we do. When animals fear death, and try to escape pain just as much as we do.
      And what surprises me more is how you manage to say that, when a vegan diet can literaly save animals, environment, starving kids in africa, e.t.c….
      And also about keeping warm in winters, there are vegan wear for it.
      However i do agree with ” trying to change an aspect of one’s culture, changes an entire cycle of life.” Because it can indeed benefit their entire lifestyle.
      Always question what you beleive to be normal culture. Because many bad things in culture has been normalised leading us to think its ok to do certain things. But if you look at this with an open mind you’d understand that we do not have the right to treat humans or non humans in a way we do not like to be treated. People bring up the lions eat deer behaviour to say its ok. But we dont do everything lions do. Cuz we have the ability to think,and survive without meat, unlike lions. You wouldnt like to be the prey of a lion. If you dont want to be food for someone else, then dont take other living beings for food. They value their lives just as much as we do. Look at the world through their eyes and you’ll understand. This is comming from a former heavy meat eater whose familly thought veganism was extreme until we began to look at things with an open mind. And by experience i can say that i feel healthier than ever. I used to even have a lot of pimples i couldnt get rid of but now most of them are gone. Im only sad i didn’t find this out sooner. And when you stop taking meat for a while it becomes somewhat disgusting, like most of us disgust eating cockroaches, worms…

      Also, one more thing, dont be fooled by meat industries’ marketing propaganda. this is why i dont look heavily into possibly biased, scientific research. If many vegans are strong, and healhy, with less problemsthen thats all that matters. But you do need to eat properly or else you could be deficient in certain nutrients just like some meat eaters lack certain nutrients.

      Reply

  • Mark Crutchley August 22, 2016 at 3:26 am

    Our greenhouse gas emissions could be reduced even further from the vegan route if we were to eat a sustainably sourced quantity of fish. This would be definition replace crops reducing fertiliser use and freeing up land which could sequester carbon. The important element in this is to ensure that fish stocks are enabled to recover from the current over-exploited levels, which in due course would enable the volume of fish in our diets to increase.

    Reply

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