florin

This is a difficult issue to approach on FT...

This guy decided to never fly again in order to reduce his carbon footprint.

Articlehttp://www.salon.com/2013/09/30/one_...ont_fly_again/

Doc Savage

Mental illness takes many forms. His seems relatively harmless to others.

WillCAD

Climate change is full of debatable points, but this article has a rather glaring mathematical improbability that casts serious doubt on 1) Holthaus's empirical research (if he actually did any before cryuing himself to sleep and vowing never to set foot on an airplan again), and 2) the accuracy of the "Carbon Calculator" at US Berkley.

The article says:
And:
Okay, so according to UCB's carbon calculator, this guy puts 33.5tons of CO2 into the atmosphere by flying 75,000 per year. Let's do some math - and let's keep it simple, because I failed Algebra I three times in high school.

33.5 tons divided by 75 = 0.446 tons of CO2 emitted per 1,000 air miles. For one passenger.

I find that hard to believe. But let's accept that and do some more math.

A cross-country flight is about 3,000 air miles, IIRC. So, on a cross-country, one passenger is responsible for 1.338 tons of CO2 emissions (0.446x3=1.338). Now, let's say this hypothetical flight is on a WN 737-300 with the pre-Evolve cabin config, seating 137 pax. 1.338x137=183.306.

So, according to the numbers from the UC Berkley Carbon Calculatronic Whizbanger Applicationomatic, a WN 737-300 puts out 183.306 TONS of CO2 on a single cross-country flight.

Um... that doesn't gibe with the stats of the plane.

According to Airliners.net, the max gross takeoff weight of a 737-300 (including plane, cargo, fuel, and pax) is 124,500lb, or 62.25 tons.

So, according to the numbers from US Berkley, the aircraft somehow emits CO2 that's more than double the weight of the plane, cargo, fuel, and pax combined. Even if the entire aircraft, all the cargo, the pax, and the fuel loaded onto it were vaporized and transmuted directly into CO2 without any loss of mass (perhaps by a Star Trek replicator, or one of Harry Potter's Philosopher's Stones), the mass would still be less than half of the amount of CO2 that UC Berkley says one of these planet-killing behemoths emits during a single cross-country flight.

UC Berkley's Carbon Calculon Add-a-ma-whoozitz application was not, apparently, written by either a mathmatics major or a physics major. Maybe the hard science folks at UCB were busy, so the application development went to the Phys-Ed department.

Red Raider LV

Oh that's so cute.

TravelPDX7

Yeah I sometimes wonder about the calculations also, like the difference in co2 flying coach vs premium, and in the end I see out as this:

The plane is going with or without me, and I'm about 6'3 190lbs and carry on about 25-50 lbs of luggage for a total of about 250lbs. THAT is what the calculation needs to be, co2 per plane configuration per mile per pound, then the math becomes simple.

IE, I weight X, I'm flying Y miles on a Z (CX 777)

I bet the other calculations are for one person in the plane and how much co2 they produce.

lorcancoyle

Perfectly valid maths - per below a 767 emits c. 100,000 tonnes of co2 per annum, say 3,000 per day. Clearly 737-300 will be lower, say 25% of that figure, ballpark 750-800 tonnes per day - seems consistent with estimate of 183 tonnes on a cross-country flight.

"The carbon-fiber composite winglets allow an airplane to save on fuel and thereby reduce emissions. The fuel burn improvement with blended winglets at the airplane's design range is 4 to 5 percent. For a 767 airplane, saving half a million U.S. gallons of jet fuel a year per airplane translates into an annual reduction of more than 4,790 tonnes of CO2 for each airplane. The addition of winglets can also be used to increase the payload/range capability of the airplane instead of reducing the fuel consumption. Airplanes with blended winglets also show a significant reduction in takeoff and landing drag."

http://www.boeing.com/commercial/aer...icle_03_1.html

acunningham

Bear in mind that the oxygen in the CO2 emitted comes from the atmosphere rather than the fuel. Carbon has an atomic weight of approximately 12, and oxygen approximately 16, and of course CO2 contains twice as many oxygen atoms as carbon, so only about 27% of the mass of the CO2 produced comes from the fuel. The other 73% or so comes from the air ingested by the engines.

Kagehitokiri

one cannot complain about carbon if one is not buying land, and planting elsewhere

page 35 (page 37 of pdf)
wilderness holdings 2012 annual report
in commerce section
http://www.wilderness-holdings.com/i...annual_reports

WillCAD

Okay, using my numbers from above, a WN 737-300 puts out 183.306 tons of CO2 on a single 3,000 mile cross-country flight.

If 73% of that mass comes from the atmosphere, and 27% comes from the fuel:

183.306 x 0.27 = 48.49
183.306 x 0.73 = 133.813

So, in order to emit 183.306 tons of CO2 on a 3,000-mile flight, 48.49 tons of fuel would have to be transmuted to the proper chemicals and mixed with 133.813 tons of outside air.

But the max fuel capacity of a 737-300 is 16,200kg/35,714lb, or 17.857 tons. Even if every atom of the max fuel load were transmuted to the proper chemicals and mixed with outside air in the 73/27% ratio, it would only produce 66.137 tons of CO2 (17.857 / 0.27 = 66.137). There would still be 117.169 tons of missing mass.

That math still doesn't add up.

But, what do I know; I failed Algebra I. Three times!

Maybe I'm going at it from the wrong perspective; perhaps it's a physics problem, instead of a math problem - the missing 117.169 tons of mass might be Dark Matter.

Kagehitokiri

http://www.co2list.org/files/calculators.htm

piper28

Nah, your problem is bringing math and logic to a climate argument.

Calder

I appreciate the sacrifice. I feel better about my upcoming flight to Vancouver already.

acunningham

We also need to multiply the 137 passengers in the original calculation by the average load factor, as not every seat is occupied on every flight. The maths still don't add up unless WN gets an extraordinarily low load factor of around 37% (which I don't beleive for a moment), but we're getting closer.

armus

He can feel better by watching the PBS / Nova show "Dimming the Earth", which talks about "global dimming" and how temperatures spiked on/after 9/11 because airplanes weren't in the air to help block out the sun.

janetdoe

You're missing a couple of factors:
1) The calculator includes a factor of 2 (to account for RFI - the fact that other greenhouse gases are emitted and that they have an increased impact on global warming when released at high altitude). So divide by 2 to get 'actual weight of carbon dioxide emitted' versus the 'carbon impact' of burning jet fuel at 30,000 feet.

2) CO2 weighs 44 amu. Of that, 12/44 = 27% is the carbon, that actually comes from the fuel. The rest of the weight is oxygen, which comes from the air. So multiply by 0.27 to get the weight of the actual carbon emitted. Then multiply by 14/12 to approximate the weight of the hydrogen in the fuel (assuming a formula of (CH2)n). So a net factor of around 32% to get the weight of the fuel burned in order to generate than much carbon dioxide.

3) You assume a 100% load factor, but the model probably assumes somewhere between 60 and 80%.

So take your 0.441 tons of "carbon impact" per thousand passenger air miles. Taking your assumption of a cross-country flight of 3000 miles, and 137 seats with a load factor of 80%, that gives you 110 passengers.

110 passengers * 0.441 tons "carbon impact" per thousand passenger miles * 3000 miles = 145 tons "carbon impact".

145 tons of CO2 of "carbon impact", divide by the factor of 2 to get the amount caused by CO2 emissions. Multiply that by 0.32 to determine the weight of the fuel burned. That gives you ~23 tons of fuel burned on this flight.

A quick google search shows that a 737 holds around 8900 gallons of fuel. Jet fuel weights bout 6.8 pounds per gallon. 8900 gallons *6.8 lbs/gal = ~60k pounds of fuel = 30 tons.

Another quick google search shows that a 737 burns on average 6000 pounds per hour. So on a 6-hour transcon, you would expect the place to burn 36k pound of fuel, or 18 tons of fuel.

Considering these are all ballpark figures, the 18, 23, and 30 tons of fuel burned are all fairly consistent, by no means impossible. (Especially considering the SWAG nature of global warming science...)

Doesn't change the fact that the author of the article is ridiculous...