Animal agriculture accounts for two-thirds of agricultural production. Emissions and animal agriculture account for about three-quarters of agricultural land use, so it's a large contributor to both of those sources of emissions.
In the U.S., over 80% of our agricultural production emissions are linked to animal agriculture, and nearly half comes just from beef. The high emissions from land use for animal agriculture are a challenge because the world is most likely going to add another two billion people by 2050.
The goal is to get greenhouse gas emissions all the way to net-zero by 2050 and diets high in animal products make it more challenging to balance those global environmental goals.
Another thing to consider is the differential impacts of the food. If you look per gram of protein, beef takes about seven times as much land, and its production emits seven times the amount of greenhouse gases as chicken production and 20 times the land and the greenhouse gas emissions as beans per gram of protein.
The goal isn't to switch over to plant-based diets in order to fight climate change, it's actually to improve agriculture as much as possible overall, and that includes animal agriculture.
As with any climate solution, it's not enough for concerned individuals to change their consumption patterns. It's about the decisions that businesses and governments make.