Oat milk vs dairy milk: we asked a sustainability expert on what's best

Meat, eggs and dairy account for 75% of our food's carbon footprint in the US. So, vegan milks can be a sustainable substitute. Leaders of one major coffee chain believe in the taste, foam-i-ness and earth-saving benefits of oat milk so much, they've made it the default milk in their coffee drinks. But how does oat milk's sustainability and nutritive value stack up?