> Beef has an outsize environmental footprint. Per gram of protein, beef requires on average 50 times more land and produces 100 times more greenhouse gases than do beans and other plant-based proteins. Replacing 30% of the beef with mushrooms in the roughly 10 billion burgers that Americans eat each year would reduce emissions equivalent to taking 2 million cars off the road, according to the World Resources Institute, an environmental think tank in Washington DC.

How do they make this calculations? Is it a proper way to present scientific data on the best scenice journal in the world?