A new article in Nature claims that the supply chain is responsible for a fairly large share of the emissions associated with food- as much as 19%, but the figure is 36% for vegetables and fruits. This runs counter to the more established wisdom from writers like historian James McWilliams that food miles matter little. This 2010 NYT editorial by Stephen Budiansky says that transportation accounts for 14% of the total energy consumed by the American food system. Clearly one big factor is exactly what counts in each number: are we including processing? Are we including transportation for the inputs such as fertilizer? (Not sure, but it seems like the Nature article might be.)
As usual, Hannah Ritchie at Our World in Data provides an array of helpful stats, concluding that "eating local only slightly reduces your emissions." For a more general summary, Tamar Haspel has some words of wisdom: think first about your diet and second about where food comes from, and keep in mind that salad is silly. Not many calories or nutrients there: just more of a crunch experience for the global rich like many of us here in Baltimore.
