curious question: if suddenly the entire population of the earth went vegan at once, would it cut down emissions by 60%?
Agriculture, total, is 10% of current US estimated greenhouse gas emission: https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
Of that 10%, a lot of that is livestock, I've heard as high as 75-90%, but vegetable agriculture is still a part of that 10%, too.
But assuming all of that was livestock, it's still only 10%.
One of the reasons for the emphasis on "go vegan" as an individual choice is that the current industrial approach to cattle (cows for milk and beef) produces more methane than carbon and in some scenarios methane will have a 10x/100x impact on outcomes (making them much, much worse) per volume than carbon. But you can't just rely on eliminating methane production to "solve" climate change, because atmospheric carbon still "sets the tone", the question of atmospheric methane is how bad the "runaway" effects get after carbon has done more than enough damage on its own.
The rough number is that apparently 10% of CO2 equivalent comes from meat farming, but don’t trust this.
What did surprise me though is that a much larger benefit would result from repurposing the feed stock and grazing land, together comprising ~25% of the earths habitable land. Land and ecosystem restoration would likely result in feedback loops in the opposite direction.
I have a friend in Denmark that used to run a small carbon neutral farm, where the carbon offsets were all generated by other activities on his land. His all in cost for a kilo of pork was 700kr, or over $100 dollars. Meanwhile, you can but a kilo of port at a supermarket for ~$20. He could only sustain this because he ran a farm restaurant selling the best burgers in town, and even these were probably a loss leader for his best-in-town fries and mayonnaise making up the difference.
"...following a phaseout of livestock production would, through the end of the century, have the same cumulative effect on the warming potential of the atmosphere as a 25 gigaton per year reduction in anthropogenic CO2 emissions, providing half of the net emission reductions necessary to limit warming to 2°C." (emphasis mine)
I think that is the actual question being asked.
The northerners did not all converge to meat eating diet out of taste, but because very few things grow up there.
I don't have the numbers but even then, 60% is simply funny.
If you meant seal-hunting latitudes - these are only tiny part of population.
Of course meat consumption was scarce, but necessary. And even so, people were malnourished back then by today's standards.
It is just not true that European commoners did not eat meat. Yes, for many centuries, the hunting of game was restricted to the aristocracy, but the amount of this game was always dwarfed by the amount of meat on farms (just as it is today for example in the US or Canada).
The Europeans of today are descended not only from these farmers that originated in the Near East and the original hunter-gatherer Europeans, but also from invaders from the East (particularly, where Russian and Ukraine are now). The most famous of these invaders are the Yamnaya, who invented wheeled vehicles and might have invented riding on horseback. These invaders were nomads and semi-nomads who relied heavily on meat and milk products.
Going back in time, from 115,000 to 11,700 years ago, glaciers covered most of Europe and about half of Asia. Below the glaciers was the largest ecosystem known to man, extending from Europe, over the Bering land bridge all the way to about where Kentucky is now. It is called the Mammoth Steppes. Only grasses grew there because those were the only plants that could survive trampling by the mammoths and other large herbivores (including the ancestors of cows). Humans could not eat the grass, and farming hadn't been invented yet, so they ate mostly meat. These humans were the ancestors of the humans mentioned earlier. We know from studies of carbon and nitrogen isotopes that humans living in the Mammoth Steppes derived most of their calories from animals that ate grass (because grass has a different effect on carbon isotopes ratios than other plants have). They might have eaten a lot of plant food, but if so that plant food contributed at most 20% of their calories (which is not surprising given how meager in human-usable calories most non-domesticated plants are).
Going back further in time, humans have been eating meat for about 2 million years. We know that because wherever we unearth human settlements from the last 2 million years, we usually find animal bones and the bones usually show marks consistent with stone tools' having been used to separate the meat from the bones. Since plant foods do not survive the way that bones do, we do not know whether humans have been eating plants for those 2 million years, but I concede that they probably have been, but again before the invention of agriculture about 11,000 years ago, it was really hard for people in most locations to get enough calories from plants to survive.