More on flights
Matthew pointed out that my calculations in the previous post neglect to consider that it's faster flying east than west. I had taken the estimated emissions of flying in economy from Heathrow to JFK, then doubled that number to get the round trip.
The calculator I used seems to give the same number whichever way I ask. I tried a bunch of other calculators, and was a bit surprised by the wide range of answers I got for the return trip:
- The estimate from the original post: 1,619 kgCO2e
- World Land Trust carbon calculator: 1,660 kgCO2e
- The Grauniad's carbon calculator: 986 kg CO2. “Airplanes also cause significant other warming effects. For your flight, these are estimated to contribute the equivalent of an additional 1,877 kg CO2.”
- ICAO carbon emissions calculator: 312.6 kgCO2 out, 312.7 back, 625.3 kgCO2 total (so ICAO don't think the direction matters much)
I think the first two are including other effects beyond pure carbon emissions in a single figure; the Graun estimates them as two separate numbers; ICAO just reports emissions. But I could be wrong!
Anyway, even the most optimistic estimate is a little over 2 years' commuting; if I'm understanding the Guardian's answer right, they think it's more like a decade.
(I picked JFK just for the sake of argument, as somewhere I have flown to several times.)