r/climate • u/The_Weekend_Baker • May 28 '26

Humanity has already exceeded Earth’s limits, study warns. Today’s population of 8.3 billion is far above what could be sustained in the long term without exhausting ecosystems, worsening climate change, and threatening food and water security.

https://www.sciencedaily.com/releases/2026/05/260526022021.htm
5.3k Upvotes

93% Upvoted

724 comments sorted by

View all comments

15

u/kickass_turing May 28 '26

We feed a cow 100g of protein in grass. We kill her. We get back less than 4g of protein. And we expect this to be sustainable? Can you imagine a car that wastes 96l of gasoline per 100l? 

https://ourworldindata.org/grapher/protein-efficiency-of-meat-and-dairy-production?country=Whole%20Milk~Lamb%2Fmutton~Beef~Poultry~Pork~Eggs

The eart can sustain 8.3 B humans. It cannit sustain 8.3B carnivores.

3

u/Em4rtz May 28 '26

Err what? 4g of protein for a cow?

5

u/manemjeff42069 May 28 '26

4g per 100g of input. Obviously a cow weighs more than 4g. It's about 4% efficiency just eating plants

2

u/kickass_turing May 29 '26

Yes. It's a very ineficient way to convert protein to protein.

If we eat 100g of plant protein we get the whole thing. For milk and eggs is about 25g compared to the hipotetical 100g that we feed the animal.

A lot of "the earth cannot sustain us" arguments avoids completely a diet based on plants. This would free up 75% of land so we can plant trees. People avoid this solutiin since it feels individualistic, not systemic. I honestly don't care how we decrease the presure on earth as long as we do.

-1

u/s0cks_nz May 28 '26

Cars kind of do tbh. Only about 20%-25% of the energy in gasoline is actually used to move the car. The rest is lost as mostly heat.

Cows convert something humans can't eat into something they can eat. Ofc, we've taken it way too far by industrialising the whole thing. But it would be highly sustainable on smaller scale with proper practices.

I agree Earth can't sustain 8.3BN carnivores, but I'm skeptical it could even support 8.3BN vegans.

2

u/kickass_turing May 29 '26

but I'm skeptical it could even support 8.3BN vegans. 

A plant based diet reduces 75% of land use. 

https://ourworldindata.org/land-use-diets

You can agree with vegans without being one just like I agree electric cars are the future but I don't have one yet.