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?