Is Local Really Greener Than Global?

Environmentalists have decried the long supply chains of the globalized world, asserting that they are responsible for significant excess pollution and waste when products could be produced locally instead. With the recession and rising unemployment, support for buying domestic also takes on a political slant, as cries for protecting local jobs mount. But when it comes to the environment and emissions, which is really worse? Is the simple assumption that buying local is always better correct?

Cost of Shipping by Land, Air, and Sea [1]

Transport Mode Cost (Cents Per Ton-Mile) Emissions (CO2 Grams Per Ton-Km)
Airplane 81 570
Truck 27 252
Railroad 2.24 200
Barge/Ship 0.72 52

Shipping goods by plane is obviously most expensive, but it’s the difference between shipping by truck, rail, and ship that stand out. Shipping a ton of freight by truck is 35 times more expensive than shipping it over water. While railroads are much more efficient than trucks, shipping by rail is still three times as expensive as barge shipping. Goods from China travel roughly 7000 miles on ship to reach California, but that distance can be covered at the same cost as only 200 miles by truck! Since most store-bound products in the US travel via truck, it’s clear that the ocean voyage is a smaller part of globalization’s environmental impact than is commonly suspected.

In calculating the environmental footprint of wine, National Geographic and LiveScience have both noted a study on the same phenomenon: a New Yorker causes less environmental impact by drinking a bottle of wine from Bordeaux than by drinking a bottle of California wine!

These calculations don’t take into account the environmental impact of production, which varies by product and country of origin. A worker in the US uses far more energy (and creates more pollution) than a worker in China, simply because his standard of living is higher. Even if a US factory is run more efficiently, a US worker owns more cars, a larger home, and drives longer distances to work than a Chinese worker who lives in a dormitory at her factory. While an exact calculation of emissions by product is laborious, it’s easy to see that the cut-and-dry notion that local goods are more environmentally friendly is questionable at best.

[1] Data for the table were source from the  US Bureau of Transportation Statistics. Since shipping cost data were not available for all transportation modes after 2001, 2001 data were used. The emissions data comes from Dr. Vino’s wine study, which in turn sourced these figures primarily from the Greenhouse Gas Protocol.

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