I don't know. Shipping is incredibly efficient these days. If only 10% of the CO2 footprint of your food comes from shipping (which is roughly right according

I don't know. Shipping is incredibly efficient these days. If only 10% of the CO2 footprint of your food comes from shipping (which is roughly right according to quick Google searches), optimizing shipping distance is really the wrong thing. Instead, you should choose the most efficient producers, wherever in the world they are located---that is, optimize the 90% term. How? Buy the cheapest food! If Turkish pistachios are cheaper than California ones, then they are probably being grown more efficiently, with lower CO2 emissions. Price presumably reflects producer costs. We certainly don't export $149 trillion of food annually. US GDP is only $16.8 trillion. I see $133 billion of agricultural exports in 2015, according to [1]. But again, I don't think this matters, and don't think that reducing food exports and imports would reduce total CO2 emissions. [1] http://www.ers.usda.gov/data-products/foreign-agricultural-trade-of-the-united-states-fatus/calendar-year/ http://www.ers.usda.gov/data-products/foreign-agricultural-t...