Los Alamos find that firestorms are highly unlikely to form under nuclear detonations, even at very high fuel loads, and so lofting is negligible. They only look at fission scale weaponry.
I think this may well misrepresent Los Alamos’ view, as Reisner 2019does not find significantly more lofting, and they did model firestorms. I estimated 6.21 % of emitted soot being injected into the stratosphere in the 1st 40 min from the rubble case of Reisner 2018, which did not produce a firestorm. Robock 2019 criticised this study, as you did, for not producing a firestorm. In response, Reisner 2019 run:
Two simulations at higher fuel loading that are in the firestorm regime (Glasstone & Dolan, 1977): the first simulation (4X No-Rubble) uses a fuel load around the firestorm criterion (4 g/​cm2) and the second simulation (Constant Fuel) is well above the limit (72 g/​cm2).
Crucially, they say (emphasis mine):
Of note is that the Constant Fuel case is clearly in the firestorm regime with strong inward and upward motions of nearly 180 m/​s during the fine-fuel burning phase. This simulation included no rubble, and since no greenery (trees do not produce rubble) is present, the inclusion of a rubble zone would significantly reduce BC production and the overall atmospheric response within the circular ring of fire.
These simulations led to a soot injected into the stratosphere in the 1st 40 min per emitted soot of 5.45 % (= 0.461/​8.454) and 6.44 % (= 1.53/​23.77), which are quite similar to the 6.21 % of Reisner 2018 for no firestorm I mentioned above. This suggests a firestorm is not a sufficient condition for a high soot injected into the stratosphere per emitted soot under Reisner’s view?
In my analysis, I multiplied the 6.21 % emitted soot that is injected into the stratosphere in the 1st 40 min from Reisner 2018 by 3.39 in order to account for soot injected afterwards, but this factor is based on estimates which do not involve firestorms. Are you implying the corrective factor should be higher for firestorms? I think Reisner 2019implicitly argues against this. Otherwise, they would have been dishonest by replying toRobock 2019 with an incomplete simulation whose results differ from that of the full simulation. In my analysis, I only adjusted the results from Reisner’s and Toon’s views in case there was explicit information to do so[1], i.e. I did not assume they concealed key results.
As a result, blending together the Los Alamos model with that of Rutgers doesn’t really work as a baseline, they’re based on a very different binary concerning firestorms and lofting and you exclude other relevant analysis, like that of Lawrence Livermore.
In my analysis, I also did not integrate evidence from Wagman 2020 (whose main author is affiliated with Lawrence Livermore National Laboratory) to estimate the soot injected into the stratosphere per countervalue yield. As far as I can tell, they do not offer independent evidence from Toon’s view. Rather than estimating the emitted soot as Reisner 2018 and Reisner 2019 did, they set it to the soot injected into the stratosphere in Toon 2007:
Finally, we choose to release 5 Tg (5·10^12 g) BC into the climate model per 100 fires, for consistency with the studies of Mills et al. (2008, 2014), Robock et al. (2007), Stenke et al. (2013), Toon et al. (2007), and Pausata et al. (2016). Those studies use an emission of 6.25 Tg BC and assume 20% is removed by rainout during the plume rise, resulting in 5 Tg BC remaining in the atmosphere.
For example, I adjusted downwards the soot injected into the stratosphere from Reisner 2019 (based on data from Denkenberger 2018), as it says (emphasis mine):
Table 1. Estimated BC Using an Idealized Diagnostic Relationship (BC Estimates Need to be Reduced by a Factor of 10–100) and Fuel Loadings From the Simulations Shown in Reisner et al. and Two New Simulations for 100 15-kt Detonations
Hi Mike.
I think this may well misrepresent Los Alamos’ view, as Reisner 2019 does not find significantly more lofting, and they did model firestorms. I estimated 6.21 % of emitted soot being injected into the stratosphere in the 1st 40 min from the rubble case of Reisner 2018, which did not produce a firestorm. Robock 2019 criticised this study, as you did, for not producing a firestorm. In response, Reisner 2019 run:
Crucially, they say (emphasis mine):
These simulations led to a soot injected into the stratosphere in the 1st 40 min per emitted soot of 5.45 % (= 0.461/​8.454) and 6.44 % (= 1.53/​23.77), which are quite similar to the 6.21 % of Reisner 2018 for no firestorm I mentioned above. This suggests a firestorm is not a sufficient condition for a high soot injected into the stratosphere per emitted soot under Reisner’s view?
In my analysis, I multiplied the 6.21 % emitted soot that is injected into the stratosphere in the 1st 40 min from Reisner 2018 by 3.39 in order to account for soot injected afterwards, but this factor is based on estimates which do not involve firestorms. Are you implying the corrective factor should be higher for firestorms? I think Reisner 2019 implicitly argues against this. Otherwise, they would have been dishonest by replying to Robock 2019 with an incomplete simulation whose results differ from that of the full simulation. In my analysis, I only adjusted the results from Reisner’s and Toon’s views in case there was explicit information to do so[1], i.e. I did not assume they concealed key results.
In my analysis, I also did not integrate evidence from Wagman 2020 (whose main author is affiliated with Lawrence Livermore National Laboratory) to estimate the soot injected into the stratosphere per countervalue yield. As far as I can tell, they do not offer independent evidence from Toon’s view. Rather than estimating the emitted soot as Reisner 2018 and Reisner 2019 did, they set it to the soot injected into the stratosphere in Toon 2007:
For example, I adjusted downwards the soot injected into the stratosphere from Reisner 2019 (based on data from Denkenberger 2018), as it says (emphasis mine):