https://astralcodexten.substack.com/p/moral-costs-of-chicken-vs-beef

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I.

I've previously argued that meat-eaters concerned about animal welfare should try to eat beef, not chicken. The logic goes: the average cow is very big and makes 405,000 calories of beef. The average chicken is very small and makes 3000 calories of chicken. If you eat the US average of 250,000 calories of meat per year, you can either eat 0.5 cows, or 80 chickens. If each animal raised for meat experiences some suffering, eating chicken exposes 160x more animals to that suffering than eating beef.

Might cows be "more conscious" in a way that makes their suffering matter more than chickens? Hard to tell. But if we expect this to scale with neuron number, we find cows have 6x as many cortical neurons as chickens, and most people think of them as about 10x more morally valuable. If we massively round up and think of a cow as morally equivalent to 20 chickens, switching from an all-chicken diet to an all-beef diet saves 60 chicken-equivalents per year.

But some people have argued that we also need to consider global warming. Cows produce methane, which is a powerful greenhouse gas. Chickens don't. How does this affect the calculations?

According to Eshal et al 2014, chickens produce about 2 kg CO2 equivalent per 1000 calories of meat, and cows about 10 kg (here "CO2 equivalent" means a collection of greenhouse gases, especially methane, that produce as much global warming as that many kg CO2). Going back to the average person who eats 250,000 calories of meat per year, the person who eats all beef is producing 2500 kg CO2 per year; the person who eats all chicken is producing 500 kg.

How much does this change things? The average US citizen produces 17.5 tons of CO2 per year. Suppose this average person was originally eating half beef and half chicken, in which case they would get 1250 kg CO2 from beef + 250 kg from chicken = 1.4 tons from beef + 0.3 tons from chicken. That leaves 15.8 tons coming from other things like cars and plane flights.

So if this average person switched to eating only chicken, their yearly CO2 production would drop from 17.5 tons to 16.4 tons. If they switched to eating only beef, their yearly CO2 production would rise from 17.5 tons to 18.6 tons. So the CO2 difference between an all-beef and an all-chicken diet is 16.4 tons of CO2 yearly vs. 18.6 tons yearly, or about 10%.

So switching from all-chicken to all-beef saves about 60 chickens per year, at the cost of 2.2 tons extra CO2, a 10% increase in your yearly production.

Nobody agrees on exactly how much it costs to offset a ton of carbon. This site says "anywhere from $0.10 per tonne to $44.80 per tonne", but eventualy settles on $3.30. QZ says "between $4 and 13 per metric ton". Terrapass sells offsets for $10 a ton; let's stick with that for now, while admitting it's at best an order-of-magnitude estimate.