Dear Renaud and Stephen, Truth often gets lost in the story. If you believe the climate models (which I have concerns about), but are the basis of the ICCP6 results, the simulations of MCB can easily provide 4W/m^2 cooling with < 10% of the clouds, (only the stratocumulus). If you seed more, you can induce an ice age, so says the climate models. If you look at the cloud models for small scale regions (resolution 20m which I strongly believe are correct), the increases in the albedo match the climate model values. There are side effects for all interventions. Please don’t ignore the fact that we use NWP rather models everyday and they do work. Stratospheric Sulphur has been shown to work, with other very significant side effects and inability to switch off. The aerosol would reach polar stratosphuric regions within ~ 4 weeks.
The weather is global. The atmosphere’s role is solely to take heat from the equator to the pole. With just MCB seeding any one of the three main sub-tropical stratocumulus cloud decks would affect the WHOLE planet, not just a region. The biggest signal would be in the polar regions. This is often forgotten when discussing climate. With a reduced AMOC, Western Europe will cool, but the ramifications around the globe are huge. My personal view that a combination of measures may well be required; relying on one seems foolhardy as each has limitations. The consequences of MCB are global and one has to understand planetary meteorology to appreciate this. The CCRA3 report (June 2021) is a far better assessment (in my opinion) than the IPPC6 WG1 report (July 2021)which is “concensusly” bland. The draft ONR document for the UK https://www.onr.org.uk/consultations/2021/external-hazards/ns-tast-gd-013-annex-3.pdf <https://www.onr.org.uk/consultations/2021/external-hazards/ns-tast-gd-013-annex-3.pdf> is a far more accurate assessment in my opinion and makes stark reading - but then I would say that as I was a co-author . Ukraine has shown that world leaders are incapable of realising the consequence of their actions. One suspects climate change is not on the radar at all, but being ready when is does hot will be significant. Alan Alan Gadian [email protected] > On 16 Jun 2022, at 15:07, SALTER Stephen <[email protected]> wrote: > > Renaud > I think that the reason for good cooling from spray under clear skies is that > they were taking a long term average and spray under clear skies has longer > to spread and a longer life. Double the drop number means a bit over 5% more > reflectivity. Because of this log term in Twomey we want the low dose over > a wide area that we get if we spray under clear skies. It is even better if > we spray just after rain which has cleaned the air which will eventually get > to somewhere with a high enough relative humidity. We are not in a hurry. > Stephen > > > From: Renaud de RICHTER <[email protected] > <mailto:[email protected]>> > Sent: Thursday, June 16, 2022 2:22 PM > To: SALTER Stephen <[email protected] <mailto:[email protected]>> > Cc: John Nissen <[email protected] <mailto:[email protected]>>; > Planetary Restoration <[email protected] > <mailto:[email protected]>>; Shaun Fitzgerald > <[email protected] <mailto:[email protected]>>; [email protected] > <mailto:[email protected]> > Subject: Re: [geo] RE: PRAG meeting and SLR: Satellite images reveal dramatic > loss of global wetlands over past two decades > > This email was sent to you by someone outside the University. > You should only click on links or attachments if you are certain that the > email is genuine and the content is safe. > Don't forget also Ahlm, L., Jones, A., Stjern, C. W., Muri, H., Kravitz, B., > & Kristjánsson, J. E. (2017). Marine cloud brightening–as effective without > clouds. Atmospheric Chemistry and Physics, 17(21), 13071-13087. > https://acp.copernicus.org/articles/17/13071/2017/ > <https://acp.copernicus.org/articles/17/13071/2017/> > > Sulfates from ships (and from fossil fuels power plants) are also effective > without clouds! > > Le jeu. 16 juin 2022 à 11:46, SALTER Stephen <[email protected] > <mailto:[email protected]>> a écrit : > Hi All > John Nissen writes below that marine cloud brightening is not so scalable as > cloud coverage is limited. > Below is a table from Jones Haywood and Boucher of the UK Hadley Centre in > the Journal of Geophysical Research 2009 showing 0.97 watts per square metre > of cooling, about half the warming problem, could come from treating just > 3.3% of the earth’s surface. This used the same spray regions all the year > round but vessel mobility would allow us to track the movement of the best > regions. > > <image001.png> > > Charlson and Lovelock in Nature 326 pp 655-661, 1987 say that low but not > high-level clouds cover 18% of the oceans. > I have sent some of you the attached calculations about sea level rise and > would be grateful if you could suggest other input assumptions. Marine cloud > brightening has the advantage of regional and seasonal control with > high-frequency and low phase-lag. > > Stephen > > > From: [email protected] > <mailto:[email protected]> > <[email protected] > <mailto:[email protected]>> On Behalf Of John Nissen > Sent: Thursday, June 16, 2022 2:04 AM > To: Planetary Restoration <[email protected] > <mailto:[email protected]>>; Shaun Fitzgerald > <[email protected] <mailto:[email protected]>> > Subject: PRAG meeting and SLR: Satellite images reveal dramatic loss of > global wetlands over past two decades > > This email was sent to you by someone outside the University. > You should only click on links or attachments if you are certain that the > email is genuine and the content is safe. > Hi everyone, > > I'm in Canada for the next week without access to zoom so next Monday's > meeting is cancelled. > > I've had a chance to do a lot of reading and this paper (1) mentions the huge > impact of sea level rise: > > More than 1 billion people now live in low-elevation coastal areas globally. > > The Greenland Ice Sheet could give us a sudden SLR of half a metre or more if > glacier avalanches are triggered by dammed internal lake collapse or > earthquake. To reduce this risk and the risk from growing extremes of > weather/climate the Arctic must be cooled as quickly as possible. > > Powerful intervention is mandatory. Stratospheric Aerosol Injection north of > 50N is our best bet. It would be wonderful if the CCRC could endorse this > strategy while SAI still has a good chance of success. Urgency cannot be > overstated. > > (MCB is not so scalable as cloud to brighten is limited. Using both SAI and > MCB might be ideal, if MCB can be deployed quickly enough at strength. SAI > has an advantage of the blanket cooling while MCB might provide more specific > cooling where it helps.) > > We need a campaign to recognise that SAI can be deployed extremely safely, > mimicking a high latitude volcano such that ozone hole is not significantly > affected and winter warming avoided. > > The solution to the immediate climate emergency is so simple yet so far from > being accepted let alone implemented - it's crazy. > > Cheers John from mobile > > (1) https://phys.org/news/2022-05-satellite-images-reveal-loss-global.html > <https://phys.org/news/2022-05-satellite-images-reveal-loss-global.html> > -- > You received this message because you are subscribed to the Google Groups > "Planetary Restoration" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/planetary-restoration/CACS_Fxpdpwa3%3Dsoq%3DMcsL%3DDRFp1PZGFJkD3CR9Y24JoYfs-uYA%40mail.gmail.com > > <https://groups.google.com/d/msgid/planetary-restoration/CACS_Fxpdpwa3%3Dsoq%3DMcsL%3DDRFp1PZGFJkD3CR9Y24JoYfs-uYA%40mail.gmail.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. > The University of Edinburgh is a charitable body, registered in Scotland, > with registration number SC005336. Is e buidheann carthannais a th’ ann an > Oilthigh Dhùn Èideann, clàraichte an Alba, àireamh clàraidh 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/DB7PR05MB5692793F7FD3557E90BDCE68A7AC9%40DB7PR05MB5692.eurprd05.prod.outlook.com > > <https://groups.google.com/d/msgid/geoengineering/DB7PR05MB5692793F7FD3557E90BDCE68A7AC9%40DB7PR05MB5692.eurprd05.prod.outlook.com?utm_medium=email&utm_source=footer>. > > -- > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/DB7PR05MB569207E2EE8136039203B5EEA7AC9%40DB7PR05MB5692.eurprd05.prod.outlook.com > > <https://groups.google.com/d/msgid/geoengineering/DB7PR05MB569207E2EE8136039203B5EEA7AC9%40DB7PR05MB5692.eurprd05.prod.outlook.com?utm_medium=email&utm_source=footer>. -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/36F779BC-C6CD-4C09-A93D-D71A3AB7399E%40gmail.com.
