# Nuclear Question (Be careful, it might blow up)
**URL:** https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803
**Category:** Factual Questions
**Created:** [March 26, 2012, 1:33am UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803 "2012-03-26T01:33:13Z")
**Posts on this page:** 16
**Page:** 2
### Author:  [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)
#### Post date: [March 26, 2012, 4:13pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/21 "2012-03-26T16:13:46Z")
Reckoning something doesn’t really cut it for a question like this. Modelling is required, and the article **Exano Mapcase** linked to explains why there is a lot of uncertainty. A firestorm in a city is not necessarily comparable to a forest fire. The more intense the fire, the greater it’s ability to introduce smoke particles into the stratosphere.
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### Author:  [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)
#### Post date: [March 26, 2012, 4:31pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/22 "2012-03-26T16:31:06Z")
Let’s see. Here’s a shot from space of the 2007 “Wicked Fire” [forest fire](http://www.cruzine.com/2010/11/16/earth-space-photography/)in Gallatin National Forest. That [was a 26,500 acre fire](http://www.bozemandailychronicle.com/news/article_69353e0e-7d8e-11df-b61d-001cc4c03286.html), which as forest fires go, isn’t that big.
The buildable area of New York City (minus streets and water) is [154,000 acres](http://www.nyc.gov/html/dcp/html/landusefacts/landusefactshome.shtml), or about six times the size of the Wicked Fire.
For point of reference, smoke from the firebombing of Dresden was detected at [15,000 feet](http://news.bbc.co.uk/onthisday/hi/dates/stories/february/14/newsid_3549000/3549905.stm), while the Mount St. Helens eruption threw a column up to [80,000 feet](http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens), so we can probably use those as our minimum and maximum.
Also compare the [Southeast Asian Haze](http://en.wikipedia.org/wiki/1997_Southeast_Asian_haze)in 1997 which covered three million square kilometers, somewhat smaller than the size of India.
Leaving aside the issue of how smoky a flaming Big Apple would be compared to a typical forest (you can try to extrapolate from **Sailboat** ’s photo if you want) it’s pretty clear that **WarmNPrickly** ’s 'hundred burning cities" – or let’s say 20 burning cities – is going to generate a metric buttload of smoke.
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### Author:  [@Michael63129](https://boards.straightdope.com/u/Michael63129)
#### Post date: [March 26, 2012, 5:05pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/23 "2012-03-26T17:05:58Z")
> [@Hermitian](#):
>
> I agree. I see no reason to think that cities burning will make any more smoke than a forest fire that burns hundreds of thousands (or even millions) of acres.
>
> Maybe they think that if a city burns together _all at once_ it will force the smoke up higher than wildfires that burn in waves or lines?
That’s pretty much the explanation given in the Wikipedia article on nuclear winter:
> [@](#):
>
> Stenchikov et al. [2006b][25] conducted detailed, high-resolution smoke plume simulations with the RAMS regional climate model [e.g., Miguez-Macho et al., 2005][26] and showed that individual plumes, such as those from the Kuwait oil fires in 1991, would not be expected to loft into the upper atmosphere or stratosphere, because they become diluted. However, much larger plumes, such as would be generated by city fires, produce large, undiluted mass motion that results in smoke lofting. New large eddy simulation model results at much higher resolution also give similar lofting to our results, and no small scale response that would inhibit the lofting [Jensen, 2006].
Obviously, they are assuming that the entire city would be more or less burning at once, plus the smoke is probably sootier and darker than from forest fires (some of which can be intense enough for stratospheric injection; not so much related to the total size but the area and material currently burning, and [pyrocumulonimbus clouds](http://www.sciencedaily.com/releases/2010/08/100826122612.htm)).
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 7:06pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/24 "2012-03-26T19:06:18Z")
> [@Alka\_Seltzer](#):
>
> Do you have a cite for this claim? In the past, single volcanic eruptions have had a measurable impact on climate.
Indeed they have had. But let’s not lose sight of the fact that the major volcanic eruptions through history have released enormously more energy than would be released by the detonation of all our nuclear devices, and have also released many megatons of both gas and particles clear into the stratosphere.
Also, as I look into this, I find the concept remains more active than I had thought it was. This [wikipedia](http://en.wikipedia.org/wiki/Nuclear_winter) article considers the current state of the idea and the research on it.
The major information that I was aware of that criticizes the concept is discussed in the “Criticisms” section, particularly in the “Firestorm formation” section.
Most notably, some of the assumptions of the nuclear winter scenarios do not appear supportable based on history. Specifically, we have had firestorms in cities - including firestorms due to the detonation of nuclear weapons - but none of those firestorms managed to inject soot into the stratosphere, which would be required if the nuclear winter scenario was to come about. Further, all the soot from these firestorms quickly rained out of the lower atmosphere.
Still further, Carl Sagan was predicting a nuclear winter type event when the retreating Iraqis lit off all the Kuwaiti oil wells as they retreated in Gulf War I - I remember watching him on TV talking about it. Nothing happened.
And finally, we have had any number of large nuclear explosions near forests and jungles, which failed to ignite firestorms in the forests and jungles, and while we have had enormous forest fires in the United States and around the world, none have injected significant quantities of soot into the stratosphere.
This is not to say that a major nuclear war wouldn’t be a cataclysm - it certainly would be, particularly since the destruction would specifically target Man and Man’s works. But nuclear winter seems to rest on a lot of assumptions that are not well supported.
I had not realized the idea was still receiving any serious consideration, but the Wikipedia article suggests it is.
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 7:11pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/25 "2012-03-26T19:11:32Z")
> [@coremelt](#):
>
> Iran wants Nuclear weapons so they can’t be invaded by the US, a reasonable concern in my opinion. Overall they are fair more stable and predictable than Pakistan, I am much more concerned about Pakistan / India volatility than I am about a Nuclear Iran.
Iran has stated publicly that it would use them to destroy Israel. I think that, given their behavior, it is quite appropriate for us to consider the possibility that they mean it.
This is not to say that I’m somehow claiming that Pakistan isn’t a threat - it certainly is and its stability (and rationality) is very questionable. And, I do agree that India-Pakistan seems like the most likely flashpoint - for now anyway.
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 7:18pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/26 "2012-03-26T19:18:34Z")
> [@kunilou](#):
>
> For point of reference, smoke from the firebombing of Dresden was detected at [15,000 feet](http://news.bbc.co.uk/onthisday/hi/dates/stories/february/14/newsid_3549000/3549905.stm),
Lower atmosphere. Will rain out.
> [@](#):
>
> while the Mount St. Helens eruption threw a column up to [80,000 feet](http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens), so we can probably use those as our minimum and maximum.
A minor “burp” as far as volcanoes go. Think Krakatoa, since that is the last one that eliminated a complete summer around the world and led to beautiful sunsets for years afterward.
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 7:29pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/27 "2012-03-26T19:29:58Z")
To get a comparison of scale, recognize that he blast from Krakatoa was heard more than 2,000 miles away, and the shock waves were recorded 7 times as they circled the earth.
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### Author:  [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)
#### Post date: [March 26, 2012, 8:14pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/28 "2012-03-26T20:14:24Z")
> [@Bemused](#):
>
> Lower atmosphere. Will rain out.
>
> A minor “burp” as far as volcanoes go. Think Krakatoa, since that is the last one that eliminated a complete summer around the world and led to beautiful sunsets for years afterward.
[Mount Pinatubo’s eruption](http://geography.about.com/od/globalproblemsandissues/a/pinatubo.htm) might be a better high end marker, given its much larger size than St. Helens’s cloud and our much better ability to quantify its atmospheric contamination than in 1883. The article attributes much of the global climate change from Pinatubo to the very large amount of sulfur dioxide released. I don’t know if a nuclear firestorm would release those amounts of SO2.
OTOH, a very large airbursted thermonuclear weapon (not that very many of those exist anymore) is capable of releasing a tremendous amount of heat over a very wide area. Your garden variety one MT weapon (and most extant devices are smaller), airbursted at optimum altitude (ballpark 7km height, if I’m doing the calculations detailed in the [nuclear weapon archive](http://nuclearweaponarchive.org/Nwfaq/Nfaq5.html) correctly), will emit radiation of at least 8 calories/cm^2 out to at least just over 9 km away. That radiation intensity will cause 3rd degree burns to exposed skin, and ignite paper, IIRC, over a \>260 square kilometer area. For one bomb.
(I find the calculations detailed in the archive to be a little ambiguous: the scaling equations they mention don’t detail whether they are slant ranges or ranges from ground zero, assuming optimum burst height. In any event, I used the lower bound, the higher one is 11.5 km away.)
As a pretty data point of who-knows-how-reliability, here’s [a wiki chart](http://en.wikipedia.org/wiki/File:Nukecloud.png) purporting to show the relationship between device yield and height of mushroom cloud. I imagine it changes greatly depending on what the device ignited beneath it.
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 8:30pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/29 "2012-03-26T20:30:55Z")
> [@Gray\_Ghost](#):
>
> [Mount Pinatubo’s eruption](http://geography.about.com/od/globalproblemsandissues/a/pinatubo.htm) I don’t know if a nuclear firestorm would release those amounts of SO2.
Only if there was a source for it.
> [@](#):
>
> OTOH, a very large airbursted thermonuclear weapon (not that very many of those exist anymore) is capable of releasing a tremendous amount of heat over a very wide area. Your garden variety one MT weapon (and most extant devices are smaller), airbursted at optimum altitude (ballpark 7km height, if I’m doing the calculations detailed in the [nuclear weapon archive](http://nuclearweaponarchive.org/Nwfaq/Nfaq5.html) correctly), will emit radiation of at least 8 calories/cm^2 out to at least just over 9 km away. That radiation intensity will cause 3rd degree burns to exposed skin, and ignite paper, IIRC, over a \>260 square kilometer area. For one bomb.
>
> (I find the calculations detailed in the archive to be a little ambiguous: the scaling equations they mention don’t detail whether they are slant ranges or ranges from ground zero, assuming optimum burst height. In any event, I used the lower bound, the higher one is 11.5 km away.)
>
> As a pretty data point of who-knows-how-reliability, here’s [a wiki chart](http://en.wikipedia.org/wiki/File:Nukecloud.png) purporting to show the relationship between device yield and height of mushroom cloud. I imagine it changes greatly depending on what the device ignited beneath it.
The nuclear burst itself would have a negligible impact on these nuclear winter scenarios. Such a scenario depends critically on the burning of all burnable objects, and the injection of the resulting soot and ash into the stratosphere so that it will remain there long enough to substantially upset the energy balance of the earth due to a lack of insolation.
The problem here is that burning cities and forests don’t have enough energy density to elevate particulates high enough into the atmosphere to get them above storms. Hence the material rains out quickly. Indeed, the presence of the material works in many circumstances to actually precipitate storm formation.
Essentially, the air columns above these fires rise and cool and spread. The fire is not and can’t be hot enough to begin with to retain the amount of heat necessary in the column so that the column can rise clear to the stratosphere. It cools off first.
The blast itself DOES have sufficient energy density, but the blast is over pretty much instantly and the amount of material lofted that high is very small.
Volcanic eruptions, if large enough, might have the energy density (I’m not sure of that…) but will have sufficient force to loft large quantities of material high enough just by kinetic effects, as if the material was shot out of a cannon. The smaller components of this lofting will remain airborne for possibly years.
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### Author:  [@Trinopus](https://boards.straightdope.com/u/Trinopus)
#### Post date: [March 26, 2012, 8:36pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/30 "2012-03-26T20:36:57Z")
> [@Bemused](#):
>
> . . . the major volcanic eruptions through history have released enormously more energy than would be released by the detonation of all our nuclear devices . . .
This is pure nitpicking, but isn’t a great deal of the energy in a volcano seismic energy – shaking, the physical motion of vast masses of rock, lava, and ash, and so on – whereas the energy in a nuclear explosion is much more directly destructive – flash, heat, and shock-wave? The bomb’s energy is more focused on very short-term harm.
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 8:49pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/31 "2012-03-26T20:49:49Z")
> [@Trinopus](#):
>
> This is pure nitpicking, but isn’t a great deal of the energy in a volcano seismic energy – shaking, the physical motion of vast masses of rock, lava, and ash, and so on – whereas the energy in a nuclear explosion is much more directly destructive – flash, heat, and shock-wave? The bomb’s energy is more focused on very short-term harm.
Sure.
But what we’re considering here is whether these devices have the capacity to harm the ecosphere to a level that is greater than we’ve seen in recorded history from the largest volcanic blasts of which we have knowledge. This would seem to require comparisons of energy releases, to some extent anyway.
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### Author:  [@Michael63129](https://boards.straightdope.com/u/Michael63129)
#### Post date: [March 26, 2012, 9:33pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/32 "2012-03-26T21:33:53Z")
> [@Bemused](#):
>
> Only if there was a source for it [SO2]…
>
> The problem here is that burning cities and forests don’t have enough energy density to elevate particulates high enough into the atmosphere to get them above storms. Hence the material rains out quickly. Indeed, the presence of the material works in many circumstances to actually precipitate storm formation.
>
> Essentially, the air columns above these fires rise and cool and spread. The fire is not and can’t be hot enough to begin with to retain the amount of heat necessary in the column so that the column can rise clear to the stratosphere. It cools off first.
The source I mentioned says that it is due to black soot, which is apparently pretty effective at blocking sunlight and fine enough to stay in the air for a while. More importantly, it also absorbs sunlight (SO2 is mostly reflective), heating the atmosphere and causing air to rise further.
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### Author:  [@Kevbo](https://boards.straightdope.com/u/Kevbo)
#### Post date: [March 26, 2012, 10:27pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/33 "2012-03-26T22:27:33Z")
> [@coremelt](#):
>
> …and the fact they apparently drive live nuclear warheads around in unmarked vans so the US can’t work out where they all are…
You mean that they transport their nukes in a way similar to how the US does it?
> **[National Nuclear Security Agency Office of Secure Transportation](https://cryptome.org/eyeball/nnsa-ost/nnsa-ost.htm)**
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### Author:  [@Bemused](https://boards.straightdope.com/u/Bemused)
#### Post date: [March 26, 2012, 10:28pm UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/34 "2012-03-26T22:28:41Z")
> [@Michael63129](#):
>
> The source I mentioned says that it is due to black soot, which is apparently pretty effective at blocking sunlight and fine enough to stay in the air for a while. More importantly, it also absorbs sunlight (SO2 is mostly reflective), heating the atmosphere and causing air to rise further.
Nothing particulate will stay in the air if it rains. To get something like that to remain airborne for more than a short time, you have to get it above the weather. That’s the point here.
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### Author:  [@Foggy](https://boards.straightdope.com/u/Foggy)
#### Post date: [March 27, 2012, 12:38am UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/35 "2012-03-27T00:38:43Z")
It obvious that we need to do some field testing. Let’s call MythBusters.
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### Author:  [@by-tor](https://boards.straightdope.com/u/by-tor)
#### Post date: [March 28, 2012, 1:47am UTC](https://boards.straightdope.com/t/nuclear-question-be-careful-it-might-blow-up/616803/36 "2012-03-28T01:47:42Z")
Hmmm, these scientists seem to disagree with your assertion, Bemused, that the smoke won’t get into the stratosphere: “The smoke-laden air rises to the upper stratosphere, where removal mechanisms are slow, so that much of the stratosphere is ultimately heated by the localized smoke injections. Higher stratospheric temperatures accelerate catalytic reaction cycles, particularly those of odd-nitrogen, which destroy ozone.”
[http://www.pnas.org/content/105/14/5307.abstract](http://www.pnas.org/content/105/14/5307.abstract)
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