A few years ago, probably after reading Jim Merkel's book Radical Simplicity, I worked through one of the carbon calculators. My carbon footprint was different than most Americans, because I lived in a house that I designed to run primarily off of renewable energy. It was eye-opening to see that four domestic airplane flights annually, three of them in the eastern US, and one to the west coast, were half my carbon footprint (note - my preferred airline carbon calculator is this one, which includes an RFI toggle). Forty percent of the total was driving a car - 18-20,000 miles a year, even though it was a 40 mpg car. Over two thirds of this was work-related, so I rationalized it, but I actually don't like driving and therefore had a double motivation to reduce auto miles.
Now living on MV, I drive much less - well under 10,000 miles annually is what it looks like, and almost all off island. Plane travel is reduced (but I'm about to go off to two trainings in Pittsburgh to ramp up the number of people in the US able to train Passive House Consultants - these are real handwringers for me) but the house as we received it has a much heavier carbon footprint than the one we left. But, we fix.
It's midnight, do you know where your carbon is?
A really cool web site that includes a great airline carbon calculator allowing graphic or direct entry of origin and destination is at http://chooseclimate.org and click on "flying off to a warmer climate."
On the air travel page, it explains why emissions injected into the upper atmosphere are so much more significant (approximately 3X as climate forcing) as the same emissions at ground level. It gives a quick primer on the relevant issues.
The home page includes a java climate model that allows the user to play around with the important variables at one of three levels of sophistication/detail. While this is pretty old and may be out of date, it is a really handy tool, and I know of no equivalent that is so accessible and instructive.
Posted by: Hal Levin | 03/29/2011 at 02:47 AM
Hal, your site has a lot more detail than the one I linked to, thanks!
Posted by: Marc | 03/29/2011 at 07:51 AM
Hi there Marc! I did a similar exercise for my 2009 energy consumption (note that I was calculating it in terms of source Btu, not carbon). I found a similar result--airplane flights were a huge portion of my total.
2010-02-19: The Big Energy Picture
http://bats22.blogspot.com/2010/02/big-energy-picture.html
-Kohta
Posted by: Bats22.blogspot.com | 03/30/2011 at 09:32 AM
Who knows what exactly are all the assumptions buried in the different forms of transport energy use? For example, a motorcycle is shown as being better than an Insight, and as a former motorcycle owner I can say I never had a bike worth calling a motorcycle that got 60 mpg. Yes, if you have a Honda 100 you'll do better, but you'll get beat up on the highway too.
The basic point that transport is a killer is borne out here, except that if Kohta didn't fly, it would be true that he uses more energy at home than in transport. Thanks, Kohta!
Posted by: Marc | 03/30/2011 at 12:41 PM