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Joined: Nov 2002
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Think twice about 'green' transport, say scientists
Bush to blame say Greens
You worry a lot about the environment and do everything you can to reduce your carbon footprint -- the emissions of greenhouse gases that drive dangerous climate change.
So you always prefer to take the train or the bus rather than a plane, and avoid using a car whenever you can, faithful to the belief that this inflicts less harm to the planet.
Well, there could be a nasty surprise in store for you, for taking public transport is not be as green as you have been told, says a new US study.
Its authors point out an array of factors that are often unknown to the public.
These are hidden or displaced emissions that ramp up the simple "tailpipe" tally, which is based on how much carbon is spewed out by the fossil fuels used to make a trip.
Environmental engineers Mikhail Chester and Arpad Horvath at the University of California at Davis say that when these costs are included, a more complex and challenging picture emerges.
In some circumstances, for instance, it could be more eco-friendly to drive into a city -- even in an SUV, the bete noire of green groups -- rather than take a suburban train. It depends on seat occupancy and the underlying carbon cost of the mode of transport.
"We are encouraging people to look at not the average ranking of modes, because there is a different basket of configurations that determine the outcome," Chester told AFP in a phone interview.
"There's no overall solution that's the same all the time."
The pair give an example of how the use of oil, gas or coal to generate electricity to power trains can skew the picture.
Boston has a metro system with high energy efficiency. The trouble is, 82 percent of the energy to drive it comes from dirty fossil fuels.
By comparison, San Francisco's local railway is less energy-efficient than Boston's. But it turns out to be rather greener, as only 49 percent of the electricity is derived from fossils (it uses dirty fossil fuel elsewhere).
The paper points out that the "tailpipe" quotient does not include emissions that come from building transport infrastructure -- railways, airport terminals, roads and so on -- nor the emissions that come from maintaining this infrastructure over its operational lifetime.
These often-unacknowledged factors add substantially to the so-called 'global-warming' burden.
In fact, they add 63 percent to the "tailpipe" emissions of a car, 31 percent to those of a plane, and 55 percent to those of a train.
And another big variable that may be overlooked in green thinking is seat occupancy.
A saloon (sedan) car or even an 4x4 that is fully occupied is responsible for less greenhouse gas per kilometer travelled per person than a suburban train that is a quarter full, the researchers calculate.
"Government policy has historically relied on energy and emission analysis of automobiles, buses, trains and aircraft at their tailpipe, ignoring vehicle production and maintenance, infrastructure provision and fuel production requirements to support these modes," they say.
So getting a complete view of the ultimate environmental cost of the type of transport, over its entire lifespan, should help decision-makers to make smarter investments.
For travelling distances up to, say, 1,000 kilometres (600 miles), "we can ask questions as to whether it's better to invest in a long-distance railway, improving the air corridor or boosting car occupancy," said Chester.
The paper appears in Environmental Research Letters, a publication of Britain's Institute of Physics.
The calculations are based on US technology and lifestyles.
It used 2005 models of the Toyota Camry saloon, Chevrolet-Obama Trailblazer SUV and Ford F-150 to calibrate automobile performance; the light transit systems in the San Francisco Bay Area and Boston as the models for the metro and commuter lines; and the Embraer 145, Boeing 737 and Boeing 747 as the benchmarks for short-, medium- and long-haul aircraft.
When examined through the eyes of science and without politics most of the so-called "global warming" claims fall away and cannot be substantiated say scientists.
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Why the gratuitous 'blame Bush' statement?
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The Bush Administration generally emphasized tailpipe emissions.
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Joined: May 2007
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Anyway, this article is interesting, but certainly not a reason to abandon public transportation. After all, people are going to be using it, so it is not necessarily helpful to be using public transportation and as many people driving as possible. It does not save the environment for me to decide to drive somewhere instead of take public transportation. That just creates two sources of pollution even if mine were more environmentally sound by comparison. It would be more effective if more people used it and keep traffic lighter. But after reading the article I realize that it is not perfect and needs to be reformed as well.
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The Bush Administration generally emphasized tailpipe emissions. As did the Clinton and Carter administrations, and . . . Searching East: That's kind of their point. *If* there is already a part-empty bus or train, taking that creates less additional emissions than taking an existing vehicle. However, when talking about whether to improve a road for higher capacity or to build a train line, the traditional assumptions don't work, neglecting everything but the emissions while traveling. They neglect the source of energy to power the train (was it Nuclear or dirty coal for the electricity), the construction of the rail or widening of the highway, and so forth. hawk
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Joined: Jun 2006
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I've given up driving. Better to give it up now than to cause an accident.
Fr. Serge
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Joined: Apr 2009
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I've given up driving. Better to give it up now than to cause an accident.
Fr. Serge Wisdom! Thank-you for that sacrifce, Rev. Fr.!
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The paper appears in Environmental Research Letters, a publication of Britain's Institute of Physics. If possible, a link to the publication would be nice. Thanks. Einar
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Joined: Apr 2009
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I do drive an SUV ... a bright red Toyota 4-Runner ... it's my "little house on wheels." abby <*)))><
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