Most estimates of greenhouse gas emissions are misleading. Cows might emit methane and co2, but that carbon came from their food, and that carbon in their food was captured from the air, so it's actually a cycle without net increase in carbon in the air. That's unlike fossil fuels, which bring carbon from the ground into the air and actually increase the carbon in the air in the process. The only real net emissions in the process of creating beef are the fossil fuels burned in the process, from transportation.

This distinction between real carbon emission, and carbon cycle is important because there's misguided notion of how much of a real difference it would make if people stopped eating meat. The decrease in emissions will be offset by a decrease in carbon capture from their food, and the net difference will be much less than assumed.

Moreover, if the process of creating meat replacements requires more fossil fuels to be burned than the natural process of growing food and feeding cattle, it might be that alternative meats are detrimental to the environment. I haven't seen a fair comparison of the net emissions of the whole process, they always count the cows farts without discounting for the carbon capture while growing their food.