The big problem is transportation. Ideally we'd have lots more muxed-use walkable neighborhoods than we have. Roughly 50% of people want to live in walkable neighborhoods, but centralized planning has virtually banned this type of low-carbon living over the past 75 years.
The second half of this sentence is incorrect. Livestock is 14.5 of global greenhouse emissions, which a) determines climate change in the US, and b) is consumed in the US, in significant part, without being accounted for under "US emissions".