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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13 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

  • 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

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