I just came across this New York Times article on environmental impact of our food choices.

This graph on greenhouse emissions places nuts at 0.1 kg CO2 compared to 1.6 kg CO2 for dairy milk so 16x less. This tells you what it take to get 50 grams of protein. This means about 5–6 cups of dairy milk or 50 cups of your average almond milk – so the numbers are 10x more dramatic per cup so 160x lower.

Article

Your Questions About Food and Climate Change, Answered

Original study published in Science:

https://science.sciencemag.org/content/360/6392/987