24 Nov 2017

Green is the new black: Plant-based diets

Anne writes*

With awareness of climate change and the environmental impacts of our behavior rising, documentaries such as “Cowspiracy” and “What the health?” seem to offer solutions to not one but several challenges we face. By adopting a plant-based diet, we (humanity) are supposedly able to better preserve the planet and to combat growing issues of malnutrition in the developed world. A question posing itself is whether or in how far the vision of a conversion to a diet made up solely by plant-based products is actually able to solve these problems. In this post we distinguish between a vegan lifestyle, in which no animal products are consumed, and eating vegan, in which the neglect of animal products is limited to diet. The impacts investigated here are the ones of the vegan eating.

Generally, vegan diets have shown to be more environmentally friendly than diets including animal products. Studies that compared eating patterns covering the same nutrients and caloric intakes have established this unequivocally. In doing so, categories that have been compared include water use, land use, eutrophication and others, or are more broadly comprised of the carbon, water and ecological footprints of eatable products. However, when they allow for variation in individual eating patterns, the individual water footprint of vegan food consumption comes to be close, equal to, or surpassing those of an omnivore. For one, this has been the case with individuals who were solely consuming fruit. This is due a need for a significantly higher volume and calorie intake due to high water, low protein and low fat contents of fruit. For the other, plant-based eating has increasingly big water footprints the more heavily it relies on processed meat and dairy replacements and/or high-fat plant products such as nuts. This is due to the water usage in processing foods as well as in growing and processing high-fat plant products. Hence it is easier to achieve a more environmentally friendly impact of food consumption by omitting animal products, but individuals need to account for the water consumption in cultivating some foods and high intake needs of certain forms of vegan eating.

Animal agriculture and all means of production coming with it make up 18-(51%) of greenhouse gas emissions (GHGs) as well as 29% of the global water footprint. Eighteen percent of total GHG emissions originate from the EU. Thus, if 10% of the inhabitants of the European Union converted to conscious plant-based eating (see image at right), global GHGs could be lowered by up to 3%. Further, the EU’s water footprint could be decreased by 3.5% if 10% of its people converted. This shows that changes in eating patterns in the developed world can have significant effects on total emissions and water consumption. Plant-based eating has also been linked to a 10%-14% decrease in mortality risk due to heightened consumption of unprocessed foods.

To conclude, plant-based eating appears to positively affect the impacts the food we consume has on our environment. However, it is important to not forget that eating vegan cannot offset all “climate sins” one can commit in the developed world: Flying frequently will still greatly enlarge one’s ecological footprint. Hence, the impression that going vegan justifies all other consumption habits is not true; adopting a plant-based lifestyle as described above is better than nothing but does not automatically warrant completely environmentally friendly living.

Bottom line: Plant-based eating can significantly change the impact food consumption has on the planet for the better. However, one needs to adhere to a balanced diet not including many processed foods in order to achieve this. Simultaneously, one must keep in mind that plant-based eating can only be the start to behaving in an environmentally friendlier manner.

* Please help my environmental economics students by commenting on unclear analysis, other perspectives, data sources, etc. (Or you can just say something nice :)


Ed Dolan said...

For those who are not ready to give up the taste of meat, consider a low-meat diet, in which many tasty recipes can be prepared using <50g of meat per person per day, as opposed to eating big pieces of meat up to 250g per portion several times a day, as served in many restaurants. Everything helps.

Nguyễn Phương Anh said...

Hi Anne, it's a really interesting and well-written blog! However, I think that you should be more prudent in your choice of sources. The source you cite from Independent does not look reliable and to make sure, I think you should look for the original paper. 18-51% is a big gap! Also, it seems odd that 10% EU citizens switching to vegan can reduce global emission by 3%. EU accounts for 18% of global emission, so 10% would account for less than 1.8%, and meat consumption would account for less than 0.9% of total emission. Therefore, global emission cannot be lowered by 3% in this scenario.

Anne said...

Dear Ed, in fact I was thinking about mentionning such a thing in my more lenghty paper because as you said, everything helps. Another idea I had was that some invasive species do need to be killed to contain their negative impacts on the environment they live in, and that eating those animals could be viewed differently from the consumption of other animal products. However I have not yet been able to find papers taking this notion into consideration.

Anne said...

Dear Phoung, the reason I chose to include the Independent source was to show that there is no consensus at all as to how much animal agriculture actually contributes to greenhouse gas emissions. Taking into consideration the amount of (monetary, economic and political) power that lies behind the interest in upkeeping high rates of animal agriculture, the gap is not surprising to me at all. If you want to "witness" the danger behind investigating the negative externalities of animal agriculture in a condensed version I would recommend you watch "Cowspiracy", which is available on netflix. I did look up the actual article behind the Independent publication, which can be found in form of a pdf: http://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf
You do indeed have good reason to point out a possible mistake in the calculations. I will look back at what I did to find those numbers and get back to you.

Anne said...

Hey! I did indeed miscalculate, thank you for letting me now. The actual change would be about 1%, not 3%. Still, I believe that the convertion of a mere 10% of Europeans to vegan eating would have such an impact on a global scale is illustrative of the effects everyday choices of peoples in the "rich world" have.

David Zetland said...


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