This was originally in reply to a now deleted reply, but it is worth calling out an alternative interpretation, we could move away from meat and make more effective usage of land. I think this is true, but still won't get us all the way.

I think even imagining people were willing to give up meat humans still use way too many raw calories for anything like sustainable organic agriculture to be workable. Maybe it would be interesting to know what percentage of the land dedicated to raising meat is for feed vs grazing. Grazing land is usually more marginal than farmland so while overall good to let it go back to nature it won't replace the sort of biodiversity that turning Kansas back to grasslands would

Also I don't trust it as much, but if it's true that humans right now make up more biomass than all land animals before we exploded it seems difficult to imagine us keeping up without continuing to have huge impacts on the planet, better to keep those impacts dense and controlled than everywhere https://www.greenpeace.org/static/planet4-international-stat...