Originally posted by pianopraze
reply to post by Aloysius the Gaul
Very interesting paper. I only read one section of it:
Aviations contribution to climat change.
But I find deeply flawed science here. A study was done in Alaska that showed that the overall effect of aviation was a net decrease. This was
confirmed after 9/11 where recorded data showed with no airplanes flying led to a net increase of temperature 2.2 degrees. So aircraft decrease the
temperature 1-2 degrees.
Is the 9/11 study you refer to this one? www.nature.com...
(with a good follow-up here - journals.ametsoc.org...
Because if so then you have misinterpreted the rsults.
It did not say that the lack of contrails resulted in a net temperature increase at all. It concluded that there was a net increase in hte difference
between daytime and night time temperatures
And it is far from universally accepted that this was the case - eg this paper www.agu.org...
at that link) postulates that any change in Daily Temperature Range as due to changes in low clouds and not high clouds - low clouds having a much
greater effect than high ones.
And both "camps" acknowledge that the actual DTR measured was well within the norms for the period concerned anyway, which makes "simple" chance at
least as likely as any other cause.
Yet this paper says the opposite, it says aviation lead to an increase in temperature:
The amount of cumulative CO2 emissions that will result in a 2° C temperature increase is relatively well known and quantified: one trillion
tonnes of CO2, half of which has already been emitted. The question that remains is “what proportion can aviation have of the half a trillion tonnes
of CO2 that can be emitted, before surface temperatures increase beyond 2° C?
another misinterpretation on your part - this section is only looking at the effect of CO2 in isolation, not the total effect of aircraft.
One of the authors does acknowledge this, in a backhanded manner:
Aviation climate impacts are due to both CO2 and non-CO2 emissions. The non-CO2 emissions include water vapor (H2O), nitrogen oxides (NOx), sulfur
oxides(SOx), hydrocarbons (HC), and black carbon (or soot) particles.
Aviation CO2, H2O and soot emissions contribute directly to climate change with positive radiative forcing (net warming). Whereas, emissions of
NOx, SOx, H2O and black carbon aerosols contribute indirectly to climate change.
Notice how he says Co2 increases temperature and No So and H2O "contribute indirectly"... i.e. they actually COOL, yet they do not say this. Nor do
they admit anywhere in this paper that aviation leads to a NET COOLING... very interesting.
Because it doesn't - you have misinterpreted the science completely.....see also below...
He goes on and obfuscates further, notice he does not mention the So2 or carbon...
Except he does - right there in the bit you quoted.....
.....which are mentioned throughout the geoengineering research as aerosols they want to use to cool the atmosphere:
In general, there is a better understanding of impacts of GHG emissions that have a direct impact on the climate than emissions that have indirect
impacts. For example, while the scientific understanding and modelling of NOx effects have substantially improved over the last few years, there is
still uncertainty regarding the exact extent to which NOx emissions from air travel affect climate change through their impact on ozone formation and
methane destruction. Similarly, H2O vapor emissions can trigger formation of contrails in sufficiently cold air masses which may persist for hours and
can potentially increase cirrus cloudiness. Direct emissions of black carbon and in situ formed aerosols can also serve as cloud condensation nuclei
which, along with background aerosols, facilitate the forma- tion of contrails and cirrus clouds. Contrails and induced cirrus clouds reflect solar
short-wave radiation and trap outgoing long-wave radiation resulting in the net positive contribution to climate change.
and there he is again mentioning carbon.....
The Alaskan study and the 9/11 study both invalidate his assumption that these contrails lead to warming.
And yet this article says that it does lead to warming - and from 2010 is the result of much more recent research than the 9/11 study....which I have
already shown is by no means uiversally accepted - news.discovery.com...
He is either not aware or directly misleading.
Or he has access to better information than you - which is something I think highly likely since he's actually studying teh situation in depth and not
"once-over-lightly" as you have done.
I editied out the rest of your baseless slander.
I find it fascinating that So2 and black carbon are admitted to in this paper at all... So those contrails ARE geoengineering, as they have 2
Well DUH! That's what "debunkers" have been saying ever since the chemtrail conspiracy started!!
edit on 14-4-2011 by Aloysius the Gaul because: (no reason given)