Alan/Stephen, I follow the geoengineering site as an environmentalist particularly interested in global warming. Also particularly interested in this contrail issue – as an ex-fighter pilot many years ago. My recollection is that contrails are also, under certain Met conditions, emitted by piston engined aircraft within the troposphere, and of course jet engines in the stratosphere. Understand the point about uncertainty as to the net global warming effect of contrails. However, I understand that water vapour is responsible for around 65% of the greenhouse effect. And that has temperature decreases with altitude within the troposphere but increases in the stratosphere there is little exchange of air mass between the two? Does this therefore imply that aircraft flying within the stratosphere and burning fossil fuels are increasing both water vapour and carbon dioxide levels in the stratosphere?
Suggests that the global warming impact exceeds that of straightforward CO2 emitted per kilogram of fuel? Or is this allegedly account for with the IPCC 1.8 X factor? Impact in ozone in the stratosphere? Tread Lightly! Dave Dave Stanley Holly House Camp Lane Grimley Worcester WR26LX 01905 641529 07966528564 www.tochallengethethinking.co.uk www.pastureforlife.org > On 15 Jul 2019, at 15:31, Stephen Salter <[email protected]> wrote: > > Alan > > 1. The contrailscience site you give is an excellent source about detecting > contrails but my question was how you can tell no contrails from very clear > skies. I show two pictures below. Which is which? > > > > <ifefmhjolbchfpci.png> > > 2. I suggest that clarity is 'clearness' in skies, language and optics. > > 3. The mention of a factor 30 was in the 2002 Nature paper. > > https://www.nature.com/articles/418601aSnips are > > Snips are: > > <jdbnmchnbhkkdmjm.png> > > <aplcnimkomblkdag.png> > > > > A relevant factor might be the financial consequences of a reduced permission > to burn hydrocarbons in the atmosphere. > > A possibly relevant paper is attached. > > Stephen > > > > > > > > > > Emeritus Professor of Engineering Design. School of Engineering, University > of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland [email protected], > Tel +44 (0)131 650 5704, Cell 07795 203 195, WWW.homepages.ed.ac.uk/shs, > YouTube Jamie Taylor Power for Change >> On 15/07/2019 14:05, Alan Robock wrote: >> 1. Contrailscience.com >> >> 2. What is clarity? >> >> 3. Where? When? I have never heard this claim before. Please show us the >> data. >> >> Alan >> >> Alan Robock, Distinguished Professor >> Associate Editor, Reviews of Geophysics >> Department of Environmental Sciences Phone: >> +1-848-932-5751 >> Rutgers University E-mail: >> [email protected] >> 14 College Farm Road >> http://people.envsci.rutgers.edu/robock >> New Brunswick, NJ 08901-8551 USA ☮ http://twitter.com/AlanRobock >> >> >> On Jul 15, 2019, at 2:45 AM, Stephen Salter <[email protected]> wrote: >> >>> Alan >>> >>> 1. How can you tell the difference between clear weather and no contrails? >>> >>> 2. Do contrails affect weather clarity? >>> >>> 3. Is there a reason why it was the clearest of clear weather for 30 years? >>> >>> Stephen >>> >>> Emeritus Professor of Engineering Design. School of Engineering, University >>> of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland [email protected], >>> Tel +44 (0)131 650 5704, WWW.homepages.ed.ac.uk/shs, YouTube Jamie Taylor >>> Power for Change >>> >>>> On 14/07/2019 15:51, Alan Robock wrote: >>>> See also https://www.nature.com/news/2008/081231/full/news.2008.1335.html >>>> for a discussion of several papers on this. >>>> >>>> Alan >>>> >>>> Alan Robock, Distinguished Professor >>>> Associate Editor, Reviews of Geophysics >>>> Department of Environmental Sciences Phone: >>>> +1-848-932-5751 >>>> Rutgers University E-mail: >>>> [email protected] >>>> 14 College Farm Road >>>> http://people.envsci.rutgers.edu/robock >>>> New Brunswick, NJ 08901-8551 USA ☮ >>>> http://twitter.com/AlanRobock >>>> >>>> On Jul 14, 2019, at 8:47 AM, Alan Robock <[email protected]> wrote: >>>> >>>>> The reported warming after 9/11 was actually a change in diurnal >>>>> temperature range. Kalkstein and Balling found that it was just clear >>>>> weather and not lack of contrails. >>>>> https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.pdf >>>>> >>>>> Alan >>>>> >>>>> Alan Robock, Distinguished Professor >>>>> Associate Editor, Reviews of Geophysics >>>>> Department of Environmental Sciences Phone: >>>>> +1-848-932-5751 >>>>> Rutgers University E-mail: >>>>> [email protected] >>>>> 14 College Farm Road >>>>> http://people.envsci.rutgers.edu/robock >>>>> New Brunswick, NJ 08901-8551 USA ☮ >>>>> http://twitter.com/AlanRobock >>>>> >>>>> On Jul 14, 2019, at 7:00 AM, Seb Eastham <[email protected]> wrote: >>>>> >>>>>> Hi John , >>>>>> >>>>>> Inconveniently, they do both. They reflect and scatter incoming solar >>>>>> radiation (cooling effect) but also absorb outgoing longwave (warming). >>>>>> At night they are purely warming, but during the day the net effect can >>>>>> be either - depending strongly on whether there are clouds beneath them >>>>>> (decreases cooling benefit), the surface albedo (sea is dark so contrail >>>>>> benefits are greater), and the surface temperature. Kärcher wrote an >>>>>> excellent review article in 2018 (Formation and radiative forcing of >>>>>> contrail cirrus) covering the degree of uncertainty in all this - since >>>>>> we have very poor records of total coverage and properties, the exact >>>>>> balance between warming and cooling is also highly uncertain. >>>>>> >>>>>> Regards, >>>>>> >>>>>> Seb >>>>>> >>>>>>> On Sun, Jul 14, 2019, 08:40 john gorman <[email protected]> wrote: >>>>>>> The report that got me into this was a research paper showing that the >>>>>>> lack of contrails just after 911 allowed a warming of the atmosphere. >>>>>>> So I came up with an idea to increase and simulate the cooling effect >>>>>>> of contrails. At the time I had never heard of the this group or the >>>>>>> word geoengineering. >>>>>>> >>>>>>> >>>>>>> >>>>>>> I now see in a recent post that contrails warm the earth. >>>>>>> >>>>>>> >>>>>>> >>>>>>> Which is correct? >>>>>>> >>>>>>> >>>>>>> >>>>>>> John Gorman >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> You received this message because you are subscribed to the Google >>>>>>> Groups "geoengineering" group. >>>>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>>>> an email to [email protected]. >>>>>>> To post to this group, send email to [email protected]. >>>>>>> Visit this group at https://groups.google.com/group/geoengineering. >>>>>>> To view this discussion on the web visit >>>>>>> https://groups.google.com/d/msgid/geoengineering/5d29a2ee.1c69fb81.57666.3e93SMTPIN_ADDED_MISSING%40gmr-mx.google.com. >>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> -- >>>>>> You received this message because you are 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https://groups.google.com/d/msgid/geoengineering/64EC2DB0-DC91-467E-9A46-2AC95EB607CC%40envsci.rutgers.edu. >>>>> For more options, visit https://groups.google.com/d/optout. >>>> -- >>>> You received this message because you are subscribed to the Google Groups >>>> "geoengineering" group. >>>> To unsubscribe from this group and stop receiving emails from it, send an >>>> email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at https://groups.google.com/group/geoengineering. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/geoengineering/899A4FCF-3516-49DC-84AB-F1B8810886F6%40envsci.rutgers.edu. >>>> For more options, visit https://groups.google.com/d/optout. >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "geoengineering" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at https://groups.google.com/group/geoengineering. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/geoengineering/98726e6b-8232-cf38-f59b-9bb164bb6ac6%40ed.ac.uk. >>> For more options, visit https://groups.google.com/d/optout. >>> The University of Edinburgh is a charitable body, registered in >>> Scotland, with registration number SC005336. >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "geoengineering" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at https://groups.google.com/group/geoengineering. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/geoengineering/98726e6b-8232-cf38-f59b-9bb164bb6ac6%40ed.ac.uk. >>> For more options, visit https://groups.google.com/d/optout. > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/geoengineering. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/654aed74-d750-6f7a-ac33-6c9c6e270c0d%40ed.ac.uk. > For more options, visit https://groups.google.com/d/optout. > <Salter hydrogen planes.pdf> > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > 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