The article was a bit light on hard values, does anyone have good sources? Googling, main pages which come up seem to indicate the impact is only ~15% of total GHG emissions [1][2]. This doesn't seem like much overall for sweeping lifestyle changes, are these values wrong or am I missing something here?

Granted [1] isn't a great source, but hard to find.

[1] https://www.meatinstitute.org/index.php?ht=d/sp/i/47385/pid/...

[2] http://www.fao.org/news/story/en/item/197623/icode/