June 8, 2009 By Blake Harris
When it comes to travel, it's not just what comes out of the tailpipes of trains, planes, buses and automobiles that impacts the environment.
Researchers from the Department of Civil and Environmental Engineering at the University of California, Berkeley, have created a framework to calculate the true environmental cost of travel.
Detailed in a paper published today in Environmental Research Letters, the new framework incorporates less-considered environmental impacts including the damage done by the power plants generating electricity for train travel and upkeep of train stations to the intensive energy costs of airport runway construction and ore extraction undertaken to build a car.
From cataloging the varied environmental costs the researchers come to some surprising conclusions, a news release notes. A comparison between light railways in both Boston and San Franciso show that despite Boston boasting a light railway with low operational energy use, its Light Rail Transit is a far larger greenhouse gas (GHG) emitter because 82 percent of the energy generated in Boston is fossil-fuel based, compared to only 49 percent in San Francisco.
Total life-cycle energy inputs and GHG emissions contribute an additional 155 percent for rail, 63 percent for cars and buses and 32 percent for air systems over vehicle exhaust pipe operation.
The researchers also touch on the effect of low passenger occupancy and show that we are naive to automatically assume one form of transport is more environmentally friendly than another. They conclude from their calculations that a half-full Boston light railway is only as environmentally friendly, per mile traveled, as a midsize aircraft at 38 percent occupancy.
Mikhail Chester, one of the researchers at Berkeley, said in the news release, "This study creates a framework for comprehensive environmental inventorying. ... Future assessment of nonconventional fuels and vehicles can follow this methodology in creating technology-specific results."
Photo by Thaths. CC Attribution-Noncommercial 2.0 Generic