Just had a look at the IPCC Special Report. Here is a bitesize summary:
* The data is from 1992
* Aviation emissions in 1992 were 2% of total anthropogenic emissions in 1992
* Aviation CO2 emissions in 1992 were 13% of all transportation related emissions in 1992.
* However, the CO2 atmospheric concentration attributable to aviation in 1992 is 1% of the total!
Some other snippets wot I noticed:
* Emissions of CO in the upper trop create more GH ozone than at the surface.
* However, aircraft sulpher and water emissions deplete trop ozone offsetting the effects to an unknown degree (more work needed).
* CO emissions deplete methane (a GH gas), estimated at 2% less than would exist without aircraft now and 5% reduction due to aircraft in 2050.
* Upper trop lower strat ozone create a local effect. Methane depletion creates a global effect, therefore predictions unreliable as to net effect despite possible global numerical cancellation.
Clearly the story is not as black and white as some believe and that this data is at odds with that reported.
Last edited by High Wing Drifter; 3rd November 2006 at 10:32.