My biggest lines of defense are:
* Dr. Kim Williams, former president of the American College of Cardiology, said "there are two kinds of cardiologists, vegans, and those who haven't read the data"
* Animal agriculture is responsible for 20-33% of all freshwater consumption globally
* Mass cultivation of animals increases the chances of pandemic
* 41% of mainland USA is used for grazing livestock, yet meat only provides 18% of our calories; feeding the world on a vegan diet could reduce farmland use by 75% or more
* Going plant-based for two-thirds of meals could reduce food-related carbon emissions by 60% (the way we produce, distribute, and refrigerate food is a huge contributor of global emissions)
* 70-75% of soybeans grown globally are for livestock, only 6% are used for human food products (meat eaters often try to claim that soy production is terrible for the environment; surprise, surprise, meat consumption is the main driver)
* most plastic in the ocean is made up of abandoned fishing gear (see https://www.nationalgeographic.com/news/2018/03/great-pacifi...)
But I do question how much of some the things you reference are actually problems.
We have plenty of fresh water. Distribution is often our problem when it comes to getting that water to humans everywhere, but stopping livestock production will not fix that.
Does it really matter how much of the USA is used for livestock grazing? Are we missing out on using that land for other things that are important to us?
I have no opinion on soybean production, but, again, does it matter that the lion's share of soybean production goes toward feeding livestock? And if soybean cultivation really is that bad for the environment, are there other things we could be feeding livestock that don't have such bad effects?
The carbon emissions suck, but are there ways to reduce these through better process?
I don't think any of these problems are unsolvable, but likely they're expensive, and there's no political will to tax the bad behavior to the point that it becomes financially better to do the right thing. Getting around that is likely easier than getting a significant chunk of the world to go vegan.
And that's the issue I have with most logical arguments around veganism. Meat production and consumption has a lot of problems, certainly, but vegans seem to believe that the only way to fix those problems is to throw the baby out with the bathwater, when there are almost certainly solutions or at least mitigations to those problems. I get that as an individual, you aren't going to fix those problems, so personally going vegan is a way for people to avoid being a part of the problem. That is a satisfying route for some people, but not for everyone.
Cattle raising and soy production (for animal feed) are major contributors to the continued loss of Amazon.
Eventually, humanity will have to accept that going vegan is the only sustainable method.
An appeal to authority. I'm mean surgeon general once called for not wearing masks until he changed his mind completely.
"* Animal agriculture is responsible for 20-33% of all freshwater consumption globally"
Why would that be problematic? There is no shortage of water where they raise animals. On the other hand there is a shortage of water in California where they grow crops on a massive scale.
"* Mass cultivation of animals increases the chances of pandemic"
That is a true, but the same can be said of large fields of monoculture crops where disease can quickly spread and destroy everything resulting in hunger.
"* 41% of mainland USA is used for grazing livestock, yet meat only provides 18% of our calories; feeding the world on a vegan diet could reduce farmland use by 75% or more"
Only if that 41% of mainland is suitable for plowing and you don't mind destroying other habitats for food production. Live stock can graze, humans cannot. Plus we don't need pesticides and insecticides on grasslands which are destroying our fresh water supplies.
"* Going plant-based for two-thirds of meals could reduce food-related carbon emissions by 60% (the way we produce, distribute, and refrigerate food is a huge contributor of global emissions)"
That is already true for vast majority of people on this planet. Think of the food pyramid.
"* 70-75% of soybeans grown globally are for livestock, only 6% are used for human food products (meat eaters often try to claim that soy production is terrible for the environment; surprise, surprise, meat consumption is the main driver) "
I don't know how real the numbers are, regardless it is not an ideal situation and we should strive towards less monulture.
For example, freshwater consumption is important in regions which lacks freshwater. Crop agriculture is however the most common source for water pollution, occurs in all regions, and is not only a major environmental problem but also harms the supply of fresh water even if its not responsible for the primary consumption. Fertilizers and pesticides being the main culprits here. Sadly there is very little food in stores that do not have a direct link to fertilizers and pesticides except for wild fish, shellfish and seaweed.
In quite a few times I have seen studies showing that the lowest carbon emission in any food group would be either shellfish, seaweed, or insects. No fertilizers, pesticides, herbicides, minimal land usage and sustainable. Vegan would exclude two of those, and seaweed is pretty rare in non-asian diets.
In general I try to look for marks of sustainability when buying food. Small producers, non-factory farm operations, local, crops that are in season, and so on. The article here focus on the issue of sex determining the eggs, but my primary priority is the area that the hen has. In EU you can have 16 hens located in a small box the size of 0.2m². That is plain cruelty and so I choose eggs under the mark that require 4m², a requirement for outside area, always access to natural lighting, and given crops grown without chemical fertilizers, pesticides or herbicides.
Is it perfect? No. Not using fertilizers, pesticides, and herbicides is still being debated and researched if they are better for the environment or worse since land usage increases from it, but since I regularly dive in the Baltic sea I am constantly reminded by the harm done already by the revolution of chemical fertilizers produced primarily by natural gas.
There's a whole strand of veganism called bivalveganism which supports the usual vegan diet + eating bi-valve creatures like mussles precisely because their cultivation seems to have a lot of positive environmental benefits (or at least, it's one of the least harmful, as you mentioned) and because they seem to rank pretty low in terms of sentience / capacity-to-feel-pain.
> Crop agriculture is however the most common source for water pollution
Again I think the most compelling rebuttal is the fact that dairy/meat is the primary driver of crop agriculture today. We can feed the world on literally a fraction of the crop agriculture that we currently do. The vast majority of that crop agriculture goes towards feeding the animals we use for dairy or meat. So in terms of thinking about the whole picture, as you mention, any problems with crop agriculture are exacerbated by meat/dairy reliance.
Thus why I go for "the whole picture" approach. Locally produced food with markings for organic and sustainability is usually devoid of burned rain forest. Small producers tend to value sustainability more than large factory farms. Crops in season tend to involve less obscurity and less complex process which can hide ecological crimes. Animal farms with fewer animals tend to care more about individual animals health than larger farms that treat animals as items.
A big reason why organic crops has a rather complex picture comes from the issue that there exist no free lunch. Farmers that do not use chemical fertilizers derived from natural gas will instead use natural fertilizers. What that actually mean from a ecological perspective is that the chemical fertilizers produced from natural gas get put in the ground to produce animal feed, the animal feed get put into animals, and the rest product in form of manure get sold as a natural fertilizers which then is used to produce organic crops. Since organic farmers need to use more manure than non-organic farmers, and the output is lower, the total amount of carbon emissions per product can be argued as higher depending on how one count and attribute emissions. Still I generally prefer organic over non-organic because it does not directly put natural gas into the ground, and I find the cost in increase land use preferable over the other trade-offs.
Sustainable grazing (most grazing isn't) is a perfectly good use of marginal land, but that cannot produce anywhere near the meat we consume. Most animal production requires producing feed from other agricultural products. It is inherently less efficient to do this. Chicken is more efficient than beef, but still much worse than just eating plants directly.
https://www.youtube.com/watch?v=MxW-JKLeu1k
Blog version w/ reference links: https://www.sapien.org/blog/why-we-should-be-eating-more-mea...
But what percentage of our protein?
The truth is pretty far from that and most people with a regular omnivore diet get enough protein just through the plants they eat without even considering the meat. The human body burns protein and most excess protein just ends up getting burned along with carbs and fat.
So while animals may take up a large percentage of protein intake, our irrationally high collective protein intake is hardly a good reason to chose meat over plants. Eating meat is really all about calorie density.
I agree with the perspective on limiting animal suffering and I buy pastured meat. I agree with the vegan perspective on many things but I think its limited and fails to consider other aspects of the human condition. I oppose the widespread mockery and lack of respect that vegans get. The health issues associated with an ethical commitment to avoiding animal products makes it more worthy of respect.
Personally, I eat more protein than I did when I ate meat, though to be fair I still eat eggs. It's not hard at all to get adequate protein.
[0] https://healthyeating.sfgate.com/worlds-main-sources-protein...
