In 70 something years we went from 60% forest coverage of earth's land mass to 30%. I can't help but wonder how it would be without any animal agriculture.
You might be interested in the book Against the Grain: A Deep History of the Earliest States by James C. Scott. I have it sitting on my desk and have watched some talks by the author, but I haven't gotten to the book yet.
https://www.youtube.com/watch?v=QO__r8Q0bmU
https://www.youtube.com/watch?v=aVwrUsib4vU
They are a bit dry, as he is an academic through and through, but he is an academic that has spent a large amount of time in the field.
"Humans and their livestock represent 96% of all mammals on earth in terms of biomass, whereas all wild mammals represent only 4%"
https://en.wikipedia.org/wiki/Biomass_%28ecology%29#/media/F...
"The standing biomass of domesticated poultry, mostly chickens, has been calculated as 5 Mt C, about three times higher than the total biomass of all wild bird species combined"
https://royalsocietypublishing.org/doi/full/10.1098/rsos.180...
Edit: highly recommend the documentary though.
and the rate at which we deforest and destroy grassland to make grazing land is ever-increasing.
1. The graphs appear to be showing that 29% of the Earth's land surface is "barren land", i.e. deserts, glaciers, rocky terrain, etc. In 1900, 48% of the NON barren land was forests, so 34% of the Earth's total land was forested.
2. In 2018 the percentage of forested non-barren land was down to 38%, or 27% of Earth's total land.
34% to 27% of total land area from 1900 to 2018 is a major difference from the parent commenter's assertion of "In 70 something years we went from 60% forest coverage of earth's land mass to 30%".
https://ourworldindata.org/land-use-diets#more-plant-based-d...
The article that I linked above looks at how much cropland we'd need to feed the entire world population if we gave up on farming animals completely. It turns out that we would end up with about the same amount of cropland, but that's only to match the current production in calories (and nothing else). Assuming the human population continued to grow, we'd have to use even more land to grow crops.
There is of course a lot of pasture that could be turned back to forest, or left to turn back to forest, on its own. But not all pasture is ancient forests. I have no idea how much forest we would regain by ceasing to feed animals on pature.