People wanting to reduce car plus airplane use of oil by 10% in a year have been expressing confusion about how to compare them. We could just add up gallons of fuel, but that is misleading from a climate change viewpoint because airplanes do more damage than cars per gallon of fuel.
(T)he overall radiative forcing by aircraft (excluding that from changes in cirrus clouds) for all scenarios in this report is a factor of 2 to 4 larger than the forcing by aircraft carbon dioxide alone. The overall radiative forcing for the sum of all human activities is estimated to be at most a factor of 1.5 larger than that of carbon dioxide alone.
Additionally, there is the age complication. Using 2001 data, the typical American drives 9,347 miles, the typical licensed driver 13,476 miles.
Age/Miles
16 – 19/7,600
20 – 34/15,100
35 – 54/15,300
55 – 64/12,000
65+/7,650
In areas with good mass transit, the typical driver uses the car less. In the SF Bay Area, this figure is 7,600 miles; in New York City, it’s even lower.
Per capita use of airplane in 2001 was 1,990 miles.
So how do we compare these figures? While waiting for Intergovernmental Panel on Climate Change to narrow the estimate, let’s assume that one gallon of oil in a jet produces twice the climate change problems of one gallon of oil used in a car, what with extra water vapor, etc. Assume your airplane gets 23.4 passenger miles to the gallon.
The typical American (not licensed driver) in 2001 used 452 gallons in the car (more if they were age 20 – 60, less if older or younger) and used another 85 gallons in car equivalent gallons while flying. Total: 540 gallons car equivalent.
For those deciding to reduce greenhouse gas emissions due to travel by 10% this year, don’t count miles used by public transportation — we can count that in future years. Friends (Quakers) have a history of laboring together on our behavior. Does it make sense to ask those who use more than 540 gallons car equivalent to consider reducing to 10% below the American average, to 490 gallons car equivalent? What are your feelings? Your understanding, both emotional and spiritual?
After all, few people use the car and airplane as much as we in the US do. Our use of oil (includes heating oil, etc) is about double that in the EU and almost 6 times that of the rest of the world. We’ve created a universe where reducing use of the car and airplane is difficult logistically and psychologically.
I am interested in comments on the method used. Should we calculate different values for parents with young children?
I am also interested in what comes us for people emotionally and spiritually when considering flying and driving less.
Another blog: Calvin Jones left a comment on the previous post advertising his blog Climate Change Action. He has some interesting posts, and emphasizes issues relevant to the European Union.
I was amused to see in the otherwise good “Inconvenient Truth” film that Al Gore spent a disproportionate amount of time FLYING around the planet spreading the gospel of carbon reduction.
[quoting Mark Twain] “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.”