Today in Awful Journalism
- Posted by ryan on June 8th, 2009 filed in Environment, Transit
So, someone emailed me this piece in New Scientist, titled “Train can be worse for climate than plane.” The gist is that when you take the full life-cycle of various modes into account, things like emissions and energy use look less favorable for rail. A sample:
True or false: taking the commuter train across Boston results in lower greenhouse gas emissions than travelling the same distance in a jumbo jet. Perhaps surprisingly, the answer is false.
A new study compares the “full life-cycle” emissions generated by 11 different modes of transportation in the US. Unlike previous studies on transport emissions, Mikhail Chester and Arpad Horvath of the University of California, Berkeley, looked beyond what is emitted by different types of car, train, bus or plane while their engines are running and includes emissions from building and maintaining the vehicles and their infrastructure, as well as generating the fuel to run them…
Including these additional sources of pollution more than doubles the greenhouse gas emissions of train travel. The emissions generated by car travel increase by nearly one third when manufacturing and infrastructure are taken into account. In comparison to cars on roads and trains on tracks, air travel requires little infrastructure. As a result, full life-cycle emissions are between 10 and 20 per cent higher than “tailpipe” emissions.
I read this and began musing on how the study didn’t appear to take land use effects into account, and how the numbers varied a great deal depending on ridership, which would be a lot higher if drivers paid for the congestion they cause. But then I figured, what the hell, may as well look at the paper.
Darned if it didn’t show that even when the full life cycle is taken into account, rail uses less energy and emits less CO2 than cars or planes per passenger kilometer traveled. Sure, the ratio of construction emissions to operation emissions is highest for rail, but rail still comes out ahead — with one exception (the one mentioned in the first lines). Life-cycle energy use for light rail in San Francisco is a tad higher than that for a large airplane, and life-cycle emissions for light rail in Boston is a tad higher than that for large and medium sized airplanes. So yes, if you could somehow take a full 777 across Boston, you’d probably be using a cleaner option than light rail. If your cross-town choice were between light-rail and a car, however, and you wanted to pick the cleaner more efficient option, light-rail is simply much, much better.
So there you are. Way to inform, New Scientist.
June 8th, 2009 at 2:48 pm
Shouldn’t they be comparing light rail to a helicoptor?
June 8th, 2009 at 3:15 pm
They could have chosen a light rail line in Portland instead of Boston, and they would have gotten very low emissions. More of the electricity supply is hydro in the northwest.
Why isn’t an electric car driving in Boston included in this comparison? Emissions would have been astronomical. Are the authors arguing that electric cars are an environmental mistake?
June 8th, 2009 at 6:02 pm
I’m curious how they came up with the energy cost of taking a jet across town. Airplanes use - relatively speaking - more energy on take off than cruise or landing. So the per passenger mile fuel use will be much higher for a shorter trip than a longer one which is one big reason why rail beats planes on shorter routes.
June 8th, 2009 at 10:17 pm
I believe one reason CO2 emissions are higher in Massachusetts is because
the electricity powering the Green Line is mostly coal-based. Also, train
systems like the Green Line with a lot of concrete tunnels and aerial
structures use a lot of energy in construction, while surface-running trains require less.
Chester’s study shows that Boston’s Green Line uses less energy than small, medium and large aircraft, and emits less CO2 than a small aircraft.
So yes, if you could somehow take a full 777 across Boston, you’d probably be using a cleaner option than light rail.
Only if the flight didn’t involve the highly polluting takeoff phase.
I did a review and critique of Chester’s study in the post Energy Use and Pollution of Travel Modes, which includes some discussion of the influence of urban design and
context.
June 8th, 2009 at 11:19 pm
This thing is getting panned all over the net, and rightly so. The authors and publishers should be embarrassed.
June 9th, 2009 at 9:14 am
I looked a little more at the report - thanks to LA for the link. I noticed a couple of other dubious points.
The energy used to build and light parking at train stations is counted as energy used by the rail line. This is significant. I find this very odd.
The energy used to build parking is grossly undercounted. The report says there are 105 million parking spaces in the US. Yet in the US there were (in 2006) 135 million automobiles and 99 million 2-axle trucks. At 3 am almost all these vehicles are parked, and many spaces are vacant. Shoup (p. 209) suggests there are at least three spaces per vehicle. If you increase the parking numbers by a factor of 8, you find that parking an automobile uses one-fifth as much energy as driving it.
June 9th, 2009 at 9:53 am
Unfortunately, I feel like giving the author the benefit of the doubt in this case. A lot of what is stated, outside of the title and opening section, is simply arguing for better community planning.
The offending statements probably ended up being a result of having to increase page views, which I guarantee happened. No one seems to care when you keep telling them it would be easy to cut carbon emissions by investing in public transportation instead of cars.
June 9th, 2009 at 11:08 am
to echo craig @3 and Laurence @4, the metrics for the jet travel across town is ridiculously incorrect. Even if the study authors included 1 take-off and 1 landing in their comparison, a light rail trip across town would involve dozens of stops and starts. Maybe if the authors had considered this fact,added in multiple take-offs and landings and also considered the fact that using a jet for local commuting would require the construction of dozens of runways, as well as the amount of circling that would be required for large planes to travel these short distances, they would have managed to come to the perfectly obvious conclusion that using passenger jets in place of light-rail is hideously inefficient. I mean really, sometimes there’s a reason for something to seem counterintuitive. Like being wrong.
June 9th, 2009 at 6:20 pm
One of the most basic elements of science is the idea that stuff works backwards as well as forwards. In this case an airliner flying at 40,000 feet is compared with a light rail vehicle. But what happens if we compare a light rail vehicle flying at 40,000 feet with an airliner traveling through the streets of Boston?
That’s right, the idea is obviously absurd. As is the original apples-to-oranges comparison.