The most interesting new insight this paper affords is that it confirms the "once in a blue moon" rarity of stratospheric smoke injections. The orignal 1983 TTAPS paper- Owen Toon is the second T, presumed their ubiquity, and postulated that teragrams of black smoke from thousands of fires lit by nuclear attacks would simultaneously rise past the tropopause, creating a hemispheric optical depth of 20 and by reducing sunlight by roughly 3 to 6 orders of magnitude,creating a lethal global deep freezelasting for months or years.
Climate communicator Carl Sagan, the S in TTAPS publically equated the modeled effects with those of the K-T asteroid impact and wrote that " The extinction of* Homo sapiens* cannot be excluded." and pronounced what he termed his "Apocalyptic predictions" to be the "robust" products of a "sophisticated one dimensional model." Writing in *Foreign Affairs *asserted that , never mind the smoke, the dust alone from a nuclear exchange 100 time smaller that TTAPS apocalyptic "baseline" case, "a (100 megaton) pure tactical war in Europe" would be equally dire. Forest fire experiments were accordingly carried out in Canada in the 80's to test TTAPS 'nuclear winter' hypothesis but did not produce high optical depths or evidence of solar plume bouyancy or stratospheric smoke transport- it has taken three decades for one natural wildfire out of hundreds to do so. Black smoke from the appallingly intense Kuwait Oil Fires also failed to penetrate the tropopause.although Sagan warned ABC *Nightline *viewers would collapse the Asian monsoon , causing a regional famine. It didn't happen. There was once a case for climate modeling hyperbole in the service of disarmament, but the Cold War is long gone, and while Alan Robock remains at liberty to call radiative forcing , and single digit temperature changes , from low optical depth model intercomparisons, "nuclear winter ",but the two most salient feature of this study are that, as was objected in the 1980's, photochemisry militates* against *othe optical depth persistance, TTAPS presumed in adducing the term 'nuclear winter" and that smoke plumes that reach the stratosphere remaiin quite rare- we had to wait more than a generation for satellites to catch one in the act. It's easy to paint a GCM l sky black- just tell the systems programmer to adjust the code, but models are not things and the material world is under no obligation to emulate that parameter changes that we make . CF https://www.nature.com/articles/475037b On Monday, August 12, 2019 at 2:56:07 AM UTC-4, Andrew Lockley wrote: > > https://science.sciencemag.org/content/365/6453/587.full > > Black carbon lofts wildfire smoke high into the stratosphere to form a > persistent plume > Pengfei Yu1,2,3,*, Owen B. Toon4,5, Charles G. Bardeen6, Yunqian Zhu5, > Karen H. Rosenlof2, Robert W. Portmann2, Troy D. Thornberry1,2, Ru-Shan > Gao2, Sean M. Davis2, Eric T. Wolf5,7, Joost de Gouw1,8, David A. > Peterson9, Michael D. Fromm10, Alan Robock11 > See all authors and affiliations > > Science 09 Aug 2019: > Vol. 365, Issue 6453, pp. 587-590 > DOI: 10.1126/science.aax1748 > Article > Figures & Data > Info & Metrics > eLetters > PDF > You are currently viewing the abstract. > > View Full Text > Log in to view the full text > via AAAS login > > AAAS login provides access to Science for AAAS members, and access to > other journals in the Science family to users who have purchased individual > subscriptions. > > Become an AAAS Member > Activate your Account > Purchase Access to Other Journals in the Science Family > Account Help > Log in via OpenAthens. > Log in with your institution via Shibboleth. > More options > Purchase digital access to this article > Download and print this article for your personal scholarly, research, and > educational use. > > Purchase this issue in print > Buy a single issue of Science for just $15 USD. > > Up in smoke > Extensive and intense wildfires in the Pacific Northwest of the United > States in 2017 injected large quantities of smoke into the stratosphere. Yu > et al. used satellite observations and modeling to characterize the history > and chemistry of that smoke. The smoke rose to altitudes between 12 and 23 > kilometers within 2 months owing to solar heating of black carbon. The > smoke then remained in the stratosphere for more than 8 months. > Photochemical loss of organic carbon resulted in a smoke lifetime 40% > shorter than expected. > > Science, this issue p. 587 > > Abstract > In 2017, western Canadian wildfires injected smoke into the stratosphere > that was detectable by satellites for more than 8 months. The smoke plume > rose from 12 to 23 kilometers within 2 months owing to solar heating of > black carbon, extending the lifetime and latitudinal spread. Comparisons of > model simulations to the rate of observed lofting indicate that 2% of the > smoke mass was black carbon. The observed smoke lifetime in the > stratosphere was 40% shorter than calculated with a standard model that > does not consider photochemical loss of organic carbon. Photochemistry is > represented by using an empirical ozone-organics reaction probability that > matches the observed smoke decay. The observed rapid plume rise, > latitudinal spread, and photochemical reactions provide new insights into > potential global climate impacts from nuclear war. > -- 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/34b90561-f710-40b3-a9d7-432e77eae235%40googlegroups.com.
