Re: [Q] what is the energy consumption of several airliners ?

From:         felton@phoenix.Princeton.EDU (phil. Felton)
Organization: Princeton Univ.
Date:         25 May 96 14:40:21 
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In article <airliners.1996.778@ohare.Chicago.COM>, C++ Freak
<> wrote:

> Of course, figures from Deutsche Airbus show a low environmental impact
> of air traffic.
> It is not the greatest: automobile traffic and fossil power plants are the
> worst, but according to other figures is is currently 2 % of the CO2 output
> which still seems low but still of concern because of:
> - increasing *rapidly* because air travel is getting cheaper and governments
>   strongly subsidize airlines and airports
> - it affects the upper atmosphere which other polluters don't. And the
state of
>   the upper atmosphere probably affects the climate more than the lower
>   atmosphere.

This is incorrect, the altitudes that are flown by commercial airlines are
<40000 feet.  The atmosphere up to the tropopause is well mixed and therefore
the altitude of emission is irrelevant, SSTs on the other hand fly higher and
NOx emissions there are of more concern.  However, note that the main source
of NOx in the stratosphere is from agricultural fertilizers!  To illustrate the
degree of mixedness note that Mauna Loa where the classical set of data on
CO2 is taken (at an altitude of about 13,000 ft) shows a ~2% annual fluctuation
due to the seasonal growth and die back of vegetation.