And vegan diets would make a big dent, look up agricultural sector emissions, look up beef emissions and methane from their burps. It’s a major factor after transport and electricity.
The major limiter of veganism is cultural. People love eating meat. It’s a major source of protein and calories, especially in developing countries. Americans are not going vegan, so it’s kind of silly, in my opinion, to focus on it as a solution.
Compare to building nuclear energy or solar / wind + batteries. China, the US, Europe, and India are all well-positioned to do this. The limitation is political will, which is more difficult than it should be, but definitely easier than convincing a critical mass of Americans to go vegan.
It's tied to their identity for a lot of people. The same kinds that will drive a huge SUV to compensate for the hole in their lives where meaning and connection is supposed to be.
The broken US voting system amplifies the effect.
They already told us. They hate anybody who isn't a cis white christian male. There's not a lot to find consensus on when one side wants healthcare for everyone and the other wants some people to cease to exist within the country.
Veganism is an individual choice, and individual choices are generally pushed by culture
Of course culture and politics influence each other in a myriad of ways, but when people start to try and push individual choices like being vegan into the political space it is never very popular
I personally would fight tooth and nail to prevent veganism from becoming a law in my country. Failing that I would immediately make plans to move somewhere else.
That's not something most countries want
Edit: I'm also not trying to equate eating meat with smoking - one is obviously more harmful to society than the other. I'm just thinking about the cultural change that happened. Culture is malleable. Laws aren't a great way to affect culture, but social pressure is really effective.
The reason for the decrease in smoking is still being researched and debate, but the main arguments that I have seen is the main role of smoking as social stress relief and as such it has been replaced by other addictions like opium use (mobile phone use, social media, and games has also been argued).
If we consider food culture to be malleable, we definitely should move to aquaculture as a main source of nutrients. Farms on land compete with forests and human activity, and land based farms uses artificial fertilizers (derived from natural gas) and massive amount of fresh water. Shellfish, invertebrates, and seaweed can provide both protein and calories, and has the lowest environmental impact of anything we eat today and can even have a positive environmental impact if farmed correctly. Changing farming from doing harm to doing good would have massive impact, and all it takes is a cultural change.
It is one of the last pieces to focus effort on.
If I stopped eating all meat and dairy it would reduce the world's annual emissions by 0.0000000026%, assuming we can ignore animal quantization and market effects which could easily actually reduce the reduction to 0.
It only makes a difference if a whole lot of other people do that. If I decide individually to do it for the climate even though I will be less happy on a vegan diet and it is not also done by a whole lot of other people I've made myself worse off for no benefit.
To get enough people to do it will require government incentives. It's hard to see how incentives specifically for this could be designed to be both effective and not so unpopular as to get the government replaced at the next election.
If it ever comes about it is far more likely to be as the result of something more general such as a revenue neutral carbon tax. That might raise the input costs for meat production shifting some people to non-meat diets. (They will still mostly prefer meat, but this way they might not blame the government as much).
Compare to other things individuals can do, like switch to EVs. For the vast majority of people with good home charging an EV will generally be as good as or better than an ICE car except that it is several thousand dollars more expensive than a similar ICE car.
That's something governments can incentivize. Subsidize the cost difference and subsidize home charging equipment purchase and installation, and you will get people switching. Not because they want to help the climate and are sacrificing something for that, but because it is an improvement to their current driving setup and it helps the climate.
The biggest wins though are in the things individuals don't directly deal with. Replace fossil fuel power plants with renewables backed with storage that just use gas occasionally for example, and to the user it is all just electricity. You don't have to convince individual they need to change their lifestyle to so this kind of change.
They also tend to use polarizing identity politics that vilify all men, or all old people, or all white people, etc, even though most of those groups are suffering with everybody else.
Obviously the requirement would have to be significantly quicker than current spread of veganism which would, as you noted, lead to a big dent in the agriculture sector.
How are your calculations taking into account the need to kill off, en masse, cattle and other animals as veganism spreads because they no longer can be considered economically sustaining for the farmer to support them?
I ask because I've never seen any calculation about this! Everybody always seems to think that veganism spreads and the cattle fairy will blink them out of existence.
When I was working for Greenpeace all the holier than thou vegans were all talking about how immoral it was to kill animals for food, not taking into account that once you no longer user those animals for food you need to kill off a lot of them. This taking into account of things always caused me to have a sneaking suspicion that they wanted the animals not to be killed, as if the farmers would be oh well we can't sell you for meat so let's just keep you on in retirement and feed you, but not have you breed, until you die of old age.
Given the influx of sudden and wide spread veganism and the collapse of the meat as food industry, what are the plans for getting rid of the bodies of lots of dead cows? I know what the plans are now with meat as food, cows are butchered, cut up, refrigerated and transported all over the world, but without meet as food none of that will happen because there would not be profit at the end to support it, so please, what is your plan?
Frankly, the whole wide-spread veganism is part of the solution seems to have the weakness of having many problematic moving pieces that are not at all planned for in any meaningful way - that I have ever seen that is.
You might argue that’s a ridiculous suggestion which is fair. The western world did mobilize for something that’s likely to end less of life that if we continue on our current trajectory.