Environmentalist often argue that it is better for the environment to buy local to reduce impact o of shipping freight long distances, here at Grist for example. In practice how does that work?
At first glance it seems true, from an earlier post: The giant container ship Emma Maersk burns 350 tons of fuel a day and "can emit more than 300,000 tonnes of CO2 a year - equivalent to a medium-sized coal power station." Thats according to a February 13 article in The Guardian article: Shipping boom fuels rising tide of global CO2 emissions.
The real question of course is fuel usage per ton-mile. From two different sources, the Appalachian Regional Commission and Maersk (via Slate) I get the following numbers:
A tractor trailer truck requires one gallon of fuel to move one ton of freight 59 miles. The same gallon of fuel moving freight by rail can move one ton 3.4 times further and 8.7 times further by barge and 10 time further by container ship.
Next distances; by sea, Hong Kong to Los Angles is about 8000 miles, Singapore to New York is 12,500 miles.
In practice of course moving some distance by truck in most cases is unavoidable. So from the point of view of a consumer located 50 miles from Los Angles, a producer 50 miles inland from Hong Kong a total distance of 8100 miles is the equivalent, in terms of fuel consumed, as a producer located 900 miles away by an all truck route.
If inland waterways and rail routes are taken into consideration area economically served by sea increases. A container, moved 50 miles by truck in Hong Kong, 8000 miles by sea, 200 miles by rail then 50 miles by truck, a total of 8300 miles, is equivalent to 960 miles moved by truck alone.
Given that fifty percent of the U.S. population lives within 50 miles of the coast; about 80% within 200 miles (here) - these figures are significant. In practice, as the cost of fuel rises the price of goods paid should more closely reflect the environmental impact so consumers should shop by price, not by distance.