Many thanks Stephen and Alan for taking the trouble to reply. It was an idle/curious enquiry – should’ve guessed it would be an incredibly complex issue. I am a bit more into global warming/carbon/cycle/ecosystem/soils and food/farming. On Climate Change and complexity, When talking on the carbon cycle like to quote Christine Jones – Australian soil scientist – “ five years ago we thought we understood about 5% of how the soil ecosystem functions, now we know quite a bit more and realise we only understand 1%”
Tread Lightly! Dave Dave Stanley Holly House Camp Lane Grimley Worcester WR26LX 01905 641529 07966528564 www.tochallengethethinking.co.uk www.pastureforlife.org > On 26 Jul 2019, at 09:37, Stephen Salter <[email protected]> wrote: > > Dave > > Water vapour is indeed a strong greenhouse gas and retains about 2.5 times > more heat but fortunately it condenses back to liquid much more easily than > CO2. > > Kevin Trenberth 1987 gives the average mass of water in the atmosphere as > 1.46 x 10^16 kg which you can compare with annual jet fuel consumption. This > would be a liquid level of 2.86 centimetre of the earth's surface. This > amount will increase as we warm the sea. Most of it is quite low in the > atmosphere. > > The evaporation /condensation residence time is about 10 days so the water > comes out very easily. Let me know if you would like papers about a way that > might do this removal by cooling the sea surface. The method would also help > Arctic ice, coral, hurricanes, sea level rise but nobody seems to want to do > any of these. > > 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 25/07/2019 20:57, Dave Stanley wrote: >> 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 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/CAGb9uZsZgCSSaugj_KU8P%2BFt%2Ba14pBpAkzG1Gr3KJY%2BrDCbXQg%40mail.gmail.com. >>>>>>>> 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/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]. >>> 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. > 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. 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