>At least a plant-based diet reduces your GHG footprint
That isn't actually true. It is a very misleading claim spread to promote veganism. It comes from comparing the raw caloric value of field corn, to the caloric value of beef. In reality, We do not actually eat field corn, we turn it into HFCS and corn oil, this reduces the energy efficiency of corn dramatically. A plant based diet also should not be based on HFCS and corn oil.
Second, beef is the worst meat to compare to, it is not an accurate representation for meat in general. Chicken being fed on corn based feed produces 5 million calories per acre, more than almost all the plant based crops a vegan diet would generally be based on, including soy, and equal to staples like wheat.
Third, even in comparing beef they do it wrong. They are comparing to hypothetical beef raised entirely on corn. There is no such beef. All beef is grass fed for the first year, they are only finished on grain.
That's interesting. I based my opinion on reports such as [1]. Do you have any (semi-)scientific references that support your opinion?
I agree that we don't eat much corn directly, but if it weren't used to feed livestock, we could use the land for something else, like potatoes or lentils or whatever grows in similar climate to corn, which are actually eaten. I'm somewhat doubtful of your claim that corn fed chicken produce 5 million calories per acre. Do you have a citation for that? The usual rule of thumb for going up one level in the food chain is that you lose 9/10th of the energy and corn only produces on the order of 12 million calories per acre. This random google result here [2] indeed claims about 1.4 million calories per acre for chicken.
>Do you have any (semi-)scientific references that support your opinion?
Does arithmetic count? The stats are available to look up yourself, the math is simple to do. But there's nobody funding publishing "debunk vegan nonsense" papers like there are people funding "make up vegan nonsense". So the only people you can find doing the math for you are just random people like the blog I link to later in this post.
>I agree that we don't eat much corn directly, but if it weren't used to feed livestock, we could use the land for something else, like potatoes or lentils or whatever grows in similar climate to corn, which are actually eaten
Most of those alternatives produce far fewer calories per acre than corn, which is the issue. An honest comparison shows most plant crops produce very low calories per acre, and require lots of diesel to produce and transport. Yes, you could grow something else. And almost all of those something elses are worse than corn fed chicken from an energy efficiency standpoint. If vegans want to argue the impact of meat vs plants in this way, then they need to apply the same standard to plants, and that means demanding that the vast majority of crops being grown are abandoned in favor of the tiny number that meet corn's energy output: corn, sugarcane, potatoes, palm. There's your acceptable vegan diet if we're going to limit things for being less efficient than corn.
>The usual rule of thumb for going up one level in the food chain is that you lose 9/10th of the energy
We're not talking about a natural ecosystem, which is what that rule of thumb is for. We're talking about animals that have been bred specifically to grow very large very quickly on very little food.
>and corn only produces on the order of 12 million calories per acre
No, corn produces 12 million calories per acre in human edible calories when converted to corn oil and HFCS. It produces 15 million calories per acre as livestock feed.
>This random google result here [2] indeed claims about 1.4 million calories per acre for chicken.
And it is very wrong. It is making up a silly number by using the human figure for corn calories per acre not the livestock feed figure. Then assuming chickens are fed 50/50 corn and soy when in reality their feed is almost entirely corn. It is also assuming a feed conversion ratio of 3, which is nearly double the actual ratio of 1.6 https://en.wikipedia.org/wiki/Feed_conversion_ratio#Poultry
You'd think that the meat industry would pay for debunking vegan nonsense papers, especially when the world starts talking about a carbon tax that would make beef a lot more expensive if they use the numbers I cited. But I'll read the links you provided and update my opinion. Thanks for looking them up for me.
Pasture is not harvested or stored, so there is no rodent or bird deaths from harvesting equipment, and no mass rodenticide usage as there is with grains.
That isn't actually true. It is a very misleading claim spread to promote veganism. It comes from comparing the raw caloric value of field corn, to the caloric value of beef. In reality, We do not actually eat field corn, we turn it into HFCS and corn oil, this reduces the energy efficiency of corn dramatically. A plant based diet also should not be based on HFCS and corn oil.
Second, beef is the worst meat to compare to, it is not an accurate representation for meat in general. Chicken being fed on corn based feed produces 5 million calories per acre, more than almost all the plant based crops a vegan diet would generally be based on, including soy, and equal to staples like wheat.
Third, even in comparing beef they do it wrong. They are comparing to hypothetical beef raised entirely on corn. There is no such beef. All beef is grass fed for the first year, they are only finished on grain.