Some of that cost could be offset by incentivizing carbon capturing farming practices like silvopasture and agroforestry. But while healthy pastures can sequester a lot of carbon, it’s nowhere near the numbers of a healthy forest. Ultimately we need to reforest a lot of land, which will reduce the grazing carrying load of the planet, and again make beef more expensive.
I get it: beef is easy, and people love it. So are fossil fuels. You can make a strong argument that both have done a lot of good in bringing the world out of poverty. But, where things stand today, it’s unsustainable.
People tend to focus just on the methane emissions of cows, but that’s probably somewhat solvable with changes to their diets — adding seaweed, etc. The real carbon cost is in land use change, chemical fertilizer production, transport, etc. The majority of our food system is set up to produce feed for animals. And the EPA numbers for agricultural emissions only focus on direct emissions from things like tilling, or gas burned by tractors. The true carbon cost of farming is likely to be much, much bigger than conventional estimates suggest.
There seems to be a fear that a mostly vegetarian / vegan diet is somehow less healthy. I’d argue that there’s plenty of contemporary science on the subject to suggest that it’s just as healthy a way to live, and perhaps even more so. But even if it’s a tossup, there’s an undeniable fact: global warming is happening, and the health effects of that greatly outweigh the health effects that can probably be solved with a couple of supplements. (Anecdotal evidence, but my kids are vegan due to allergies, and they’re thriving. It’s never been easier to be vegan. My parents were for a time when I was a kid, and let me tell you, things have come a long way.)
We are on the right track with getting people to switch red with white meat, a single weekly day without meat, ect. But it is with all likelihood not something that we can do over the next decade. It's something we instill in the younger generations and as they grow up it will happen.
Eventually, the ground will become depleted of phosphorous and potassium. Other trace elements tend to take a really long time to deplete, especially in clay.
For every product that leaves the farm, it takes something from the ground. Some can be amended with legume plants, but minerals will deplete at some point - adding them yearly is responsible farming.
That said it still could run into problems with other requisite elemental depletion in soil even with assistance of things like bacteria. If the plants need calcium and it is all extracted then thr farm would be limited to simpler life that doesn't need any trace elements. If say algae can get by on just atmospheric gas components, water, and sunlight indefinitely then a hypothetical algae farm could run indefinitely. But there isn't much of a market for algae.
Yes, the expansion of agricultural land is almost always bad. Unless its expansion into desert, and isn't depleting water (which is almost never the case).
But, sheep, cattle and especially pigs provide useful products in the farming cycle, essential if you want to cut out oil based fertilisers.
Thats not to mention that most of the country side of Europe looks the way it does because if farming sheep or cattle.
Pasture has its own biodiversity. Simply stopping all animal consumption would leave us more dependent on fertilisers in the short to medium term. It would also cause rapid local environmental changes, that would have interesting side effects.