At first glance, it may appear that New York City is an incredibly un-green place to live. There are so many buildings and cars and roads... how could it possibly be an eco-friendly city?
On the other hand, millions of New Yorkers don't own cars, and even those who do often take public transportation. There is far more walking as a part of daily life than in most places in the country - no house-car-office-car-house pattern here! If I want to go anywhere on the eastern seaboard, all I have to do is hop on a bus or a train.
But is public transportation really greener than driving? What about all the time? Here is a great article from Slate magazine discussing the issue - it references a study from the University of California, Berkely to talk about the effects that different forms of public transportation on the environment as compared to normal cars.
The links are there in case you want more detail, but here's the point for those of you who are happy with the nutshell version:
Basically, public transportation is far better than cars at peak hours (as one would expect) when there are lots of people using it. However, trains and buses are much worse than cars at off-peak hours. Generally, a normal car needs three or more passengers to break even with a train. The average passengers for a car is a mere 1.58 - half as many!
When there are not many people aboard, however, buses are the worst environmental option, followed by a train and then a car. But in general, and especially in NY where a car may not be an option, I'll stick with my public transportation and feel good about it.
Of course, bikes and good old fashioned walking win over everything.
Just some thoughts to mull over on your daily commute, whatever that may be!
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2 comments:
Hey
So this is something I actually have quite a bit of knowledge/background/interest in b/c I've worked at an environmental consulting company for two summers and actually help build the GHG inventory for Westchester County.
So let's state some assumptions -- "Green" is generally defined by the amount of greenhouse gases, GHG, released/emitted in the life cycle of an item. GHG including CO2, N2O, NH4, etc etc... but mostly it boils down to the Global warming potentials, GWP, of each of these gases -- the standard GWP used is based on the Kyoto protocol's TAR (or maybe they're on FAR already) but these are accepted world wide standards of measuring GHG and potencies... so for instance Methane is 12 times as "potent" as CO2, so 1 MT of NH4 released = 12 CO2 equivalents...
However, no where in the Kyoto protocol or general does it talk about NOx and SOx emissions b/c those are technically not GHG.. they don't have the same effect as GHG -- really they're the cause for acid rain -- so i'm a little peeved that the Berkeley study included that in the reasons why cars may be better in trains -- it's like saying argyle is a nice color -- it's not a color.
Ok moving on from that. So I've defined your wondering as determining if because of all the public transportation, are NYC denizens emitting less GHG per person than the average US citizen.
So i looked up PlaNYC -- they claim that in 2005, NYC logged their GHG emissions at 63.1MMT of CO2Eq. Also according to their PlaNYC report, they claim that 21% of their emissions are based on transportation -- this equals 13.3 MMT of CO2Eq. Now, I'm not completely familiar with the group they're reporting their emissions through -- but I think it's fairly safe to assume that they use the same principles as every other reporting protocol. Therefore, this transportation emission should cover everything that NYC governs. This would include the MTA subways & buses, the Metro North, LIRR (all owned by MTA, which is NYC governed), as well as the Path trains (governed by the NY/NJ Port Authority, which was determined a few years ago that it was technically owned by NYC, and not NJ), as well as any gasoline/diesel consumed by any vehicle/boat/ferry that is registered in the 5 boros. We can then take this 13.3 MMT and divide it by the number of people who live in NYC in 2005 -- 8.14mm people. This gives us an average of 1.63 metric tones of GHG emitted by the average denizen of NYC in 2005.
Of course this calculation is a high estimation because we can claim that the 8.14mm people number doesn't include the millions of Jersey/NY/tourist people who commute to NYC daily while not using any NYC based transportation -- i.e. people who drive their own vehicles and people who take NJ Transit. AND this calculation is also low b/c we can say that there are also people who live in NYC who have vehicles that are not registered to NYC but are still releasing GHG in the city... so let's call both of these estimate deviations to be roughly equal and use the 1.63 MT/person number for the average NYC person.
Compared to the National average: the US EPA states that about 1,900 MMT of CO2Eq is emitted in 2005 for transportation. same reporting protocol applies... divide by the 2005 national population of 299mm people gives 6.35 MT of CO2Eq transportation emissions for the average American citizen.
so 1.63MT < 6.35 MT.
Therefore, I'd say that YES! the public transportation has indeed made NYC a greener place, seeing as the average NYC person produces about 1/4th the amount of the average American when it comes to transportation GHG emissions.
Great points - thanks for the comment!
Re: your being peeved about including NOx and SOx in the study - remember that the study was about total environmental impact, not just greenhouse gases. They even included factors as seemingly small as grass grown on the side of the road! In those terms, then, NOx and SOx and acid rain are definitely factors that should be looked at. Reducing the issue to only GHGs could be seen as too simplified.
I also wonder what happens when we consider NYC cabs...though not part of the "public transit system", they might as well be, given their ubiquity. They are transitioning to hybrid cars, which is a great move, but the sheer number of vehicles included must add a huge 'environmental burden' onto each New Yorker.
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