You may be aware that there's a airline running flights between Oxford and Cambridge, as from February 1st this year. Now, were this a jet service, the waste and emissions would be enormous. As it is calculations suggest that, in the absence of alternative public transport, the service does NOT in fact emit more than private travel. However, Oxford and Cambridge green groups are at present considering if action is still necessary. Will update with info when it comes. For info on the airline see www.skycommuter.com.
flying Oxford to Cambridge - CO2 emissions
Guy, I haven't looked at this closely but I find it hard to believe that flying uses less energy than driving a fuel efficient car. What assumptions have been made? Surely there isn't an absence of alternative public travel, it is just that it is hard to do day trips. The X5 bus service takes 3.5 hours according to the time tables.
Extraordinary but probably true
It does sound bizarre that flying may be more efficient than driving, but in this particular case, it is probably true. The provision of public transport between Oxford and Cambridge is now so bad, that more fuel is burnt by taking the windy route by road than nipping into an aircraft! (And of course, for those busy little academics and businessmen, it shears off hours.)
I'll take the liberty of quoting Oxford Green Councillor Matt Sellwood's calculations on this - sure he won't mind:
"My calculations are basically as follows:
Plane - Piper Navajo Chieftain, which is propeller driven. This means
that, unlike jet planes, there is no 'climate forcing' effect - i.e. it has much the same impact as if it were trundling along the ground. It holds nine passengers.
It uses about 38 gallons of petrol per hour. In a 30 mins flight, 19
gallons of petrol.
Distance from oxford to cambridge by road = 143 kilometres, or roughly 89 miles.
On that basis, if the 9 passengers travelled by road instead of by air (all in seperate cars) they would need to get about 42 miles to the gallon. This is perfectly possible - and in fact, they would probably get less than this, so them all travelling by car *would* be more polluting than them all taking the plane.
Obviously there are assumptions here - the plane would have to be running full, and not running its engine for ages while on the ground - but basically, it isn't much more polluting than people driving their cars.So if we are going to do this campaign, it needs to focus on the need for a decent public transport link between the two cities."
That said, we probably WILL be campaigning about this - precisely to generate pressure for better public transport. Re-open the Varsity Line!
See:
http://en.wikipedia.org/wiki/Varsity_Line
http://www.oxford2cambridge.net/
fuel used during take off?
I think that 38 gallons per hour assumes you have reached cruising height. I would imagine that take off would involve a lot more fuel. Also a load factor of 100% is unrealistic, easyjet only achieves 85% or thereabouts.
What about the GW effect?
I wonder whether the comparison looks purely at fuel consumption or also at GW effects. The Royal Commission on Environmental Pollution estimate that the global warming effect of aviation is three times that of its CO2 emissions. In order for cars to be worse in this instance, one would have to show that they emitted at least three times as much CO2. And, by the way, if nine people can share a plane, can't they fit into two ordinary cars between them? If there is no decent public transport, what about a car sharing scheme?
Almuth Ernsting
Aircraft forcing effects
Guy said the aeroplane was a small propellor-driven type and therefore had no additional radiative forcing aerosol effects, presumably partly because it is low-flying.
The 2.7x mean multiplier for jet aircraft assumes a 100-year window, I believe. However, over many millenia, most of the effect comes from the persistence of CO2 in the biosphere, i.e. becomes very similar to any other combustion of similar petroleum fractions.