Saturday, May 03, 2008

Transportation and Carbon-Conscious Consumers

As a sector, transportation is certainly a significant source of carbon emissions. But perhaps because it is so visible, or even tactile, transportation gets a lot of attention, and people tend to overstate its role in embodied emissions. Some recent NY Times articles make references to some related data which are worth quoting:
From the Green Issue of the Magazine: “It is the locavore’s dilemma that organic bananas delivered by a fuel-efficient boat may be responsible for less energy use than highly fertilized, nonorganic potatoes trucked from a hundred miles away. Even locally grown, organic greenhouse tomatoes can consume 20 percent more resources than a tomato from a far-off warm climate, because of all the energy needed to run the greenhouse.”

The same issue also quoted the famous New Zealand studies, though in a somewhat skeptical tone: “A handful of studies have recently suggested that in certain cases under certain conditions, produce from places as far away as New Zealand might account for less carbon than comparable domestic products.”

Also, when Timberland studied the embodied emissions of its shoes, “the company was surprised to find that transportation may account for less than 5 percent of its greenhouse-gas emissions — while almost 80 percent may come from making the leather, a process buried deep in its supply chain.” (Note however that Timberland seems to have overestimated the emissions related to the leather.)

The above study is consistent with Weber and Matthews’ study on the embodied emissions of imports into the United States, which suggests that “CO2 emissions due to international freight transport are unlikely to increase the totals [of embodied emissions in imports] by more than 10%.”

In an article on the environmental impact of groceries, it was calculated that a bottle of European wine drunk in New York has 1.4kg of embodied CO2, while a Napa bottle would have 2.5kg. Ironically, in this case, the major difference does lie in transportation, since Napa wine is trucked to New York, while French wine is shipped, thus consuming far less carbon per mile shipped.

So much for drinking local (or at least national.)

Finally, a hopeful note in today’s article on transportation’s direct carbon footprint. “A paper presented by Travelport at the World Economic Forum in Davos in January… stated that consumers want information about their carbon footprint as it relates both to business and personal travel. 'That desire for information has the potential,' the paper said, 'to reshape the travel policies companies set and the choices companies and consumers make across a broad range of decisions: how they travel; when and where they travel; what airlines, hotels, and rental car companies they use; where they hold meetings and events — even whether they travel at all.'
Whatever the impact of the transportation sector on global carbon emissions, it will be interesting to watch the impact of carbon-conscious consumers on the transportation sector.