this post was submitted on 31 Dec 2025
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How much meat would be ok? (lemmy.world)
submitted 1 day ago by jayambi@lemmy.world to c/askscience@lemmy.world
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I've read in an Article that meat production causes a lot of co² emission. Now I was wondering if we stopped eating meat completely, would that be sufficient to get under the threshhold of emissions what the planet can process? What is that threshold? Where are we now? How much does meat add to this?

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[–] anamethatisnt@sopuli.xyz 29 points 1 day ago (2 children)

Danish research from March 2025:

255 grams per week. That's the short answer to how much meat you can eat without harming the planet. And that only applies to poultry and pork.

Beef cannot be eaten in meaningful quantities without exceeding planetary boundaries, according to a scientific article published by a group of DTU researchers in the journal Nature Food. So says Caroline H. Gebara, postdoc at DTU Sustain and lead author of the study.

American study from 2016:

Abstract
[...]
Transitioning toward more plant-based diets that are in line with standard dietary guidelines could reduce global mortality by 6–10% and food-related greenhouse gas emissions by 29–70% compared with a reference scenario in 2050.

American study from 2022:

Based on the model, published in the open-access journal PLoS Climate, phasing out animal agriculture over the next 15 years would have the same effect as a 68 percent reduction of carbon dioxide emissions through the year 2100.
This would provide 52 percent of the net emission reductions necessary to limit global warming to 2 degrees Celsius above preindustrial levels, which scientists say is the minimum threshold required to avert disastrous climate change.

[–] volvoxvsmarla@sopuli.xyz 3 points 1 day ago

255 grams per week is a lot more than I'd expect. Just for reference: the DGE - German Nutrition Society - recommends limiting intake of meat and meat products of not more than 300 grams per week, which is based on health aspects rather than environmental.

[–] commie@lemmy.dbzer0.com 9 points 1 day ago (1 children)

the American study from 2022 is just warmed over tilman Clark (that American study from 2016), and the Danish study also depends on tilman Clark. so we should look at their methodology.

I did.

they compare a wide range of data from lca studies, even though this violated the best guidance on lca data.

lca studies are a bit like grand juries: the person designing the study can pretty much get any result they want.

and since these studies are all disparately methodized, you cannot combine them.

it's possible the conclusions are correct, but these papers are not sufficient evidence to be believed.

[–] anamethatisnt@sopuli.xyz 3 points 1 day ago (1 children)

I don't have full access to the danish study, so I will have to take your word for it.

I do see that Tilman D, Clark M (2014) Global diets link environmental sustainability and human health. Nature 515(7528):518–522. is referenced in the 2016 study and the 2022 study.

[–] commie@lemmy.dbzer0.com 1 points 1 day ago (1 children)

the danish study is actually worse in some ways. it additionally cites poore-nemecek 2018, who themselves referenced tilman-clark, but egregiously gathered even more lca meta-analyses, and created something of a meta-meta-analysis of lcas. it's bad science all the way down.

[–] anamethatisnt@sopuli.xyz 3 points 1 day ago (1 children)

Do you have any links for someone who wants to read more about these LCA and why they're not combinable?

[–] commie@lemmy.dbzer0.com 1 points 1 day ago

hilariously, you can read the references from poore-nemecek, where the meta-studies they cite, themselves explain the problems with combining lcas, but then say "we're gonna do it anyway".

understanding how lca studies are conducted should be sufficient to understand why meta-analyses are misuses of the data, and the wikipedia article about lcas does a pretty good job of explaining the issues with the methodologies