Nuclear Winter - new simulations and studies

[K. A. Pital]

We all know that Sagan's model (TTAPS) of nuclear winter is "bunk", but what of newer models and studies like the 2007 Journal of Geophysical Research article, etc.?

They seem to confirm the reality of a global cooling (incidentally corroborating the idea of using nuclear bursts to stem global warming if necessary), with timespans over a decade that is bad enough on it's own, and disastrous effects on agriculture.

Any thoughts?

[The Romulan Republic]

I remember reading that the effects of a nuclear war would be limitted largely to the Northern Hemisphere. Is this confirmed in these new studies? I've been thinking of hopping on a plane to New Zealand if it ever looked like World War 3 was about to start.

[starslayer]

I remember reading that the effects of a nuclear war would be limitted largely to the Northern Hemisphere. Is this confirmed in these new studies? I've been thinking of hopping on a plane to New Zealand if it ever looked like World War 3 was about to start.

Just the opposite. The new studies indicate that the effects of nuclear winter would be global, not simply restricted to the latitude bands around the majority of the explosions. Besides, under the most likely scenario today (India and Pakistan go at it), you'd be better off staying in the US or Canada, given the fact that both countries have extensive, well-developed agricultural and transportation infrastructures, and they happen to be where you are currently living.

As for the new research itself, I find the largest question is how high does the smoke go? And how much of it goes to what height? Quite a bit of stuff is launched into the air in the initial explosion, but this should be tiny in comparison to what the fires put up (this is counting the atmosphere as a whole, not how high it goes). If the plumes rise very high, to say the jet stream level, it should be obvious that this would severely affect climate; just look at Tambora, Krakatoa, Pinatubo, etc. On the other hand, if most of the smoke stays low, say under 10-20,000 feet, it should fall out relatively quickly and the effects would stay localized, as now mountain ranges and other terrain features can have large effects on where the stuff goes.

This was also discussed in Physics Today, and it hasn't gone behind a subscriber wall yet.

[The Duchess of Zeon]

It's been known for quite some time that there would be a "nuclear autumn" from a major nuclear war with many tens of thousands of devices exchanged, more or less exactly like similar events such as the eruption of Mount Tambora which created the "Year without a Summer". note that Tambora ejected 1.6E11 cubic metres of debris into the atmosphere either temporarily or long-term, with 1.4E14 kg of pyroclastic trachyandesite being ejected. 1816 was the second coldest year since 1400, the coldest being 1601, after the eruption of Huaynaputina in Peru in 1600. Average global temperature was reduced by 0.7 degrees C and remained low for a while; it was still reduced from the pre-eruption figure by 0.29 degrees C in 1818. Up to 120 million tonnes (yes, 120 million tonnes) of sulphur dioxide was injected into the atmosphere by Tambora. The megatonnate of Tambora? About 24,500 MT, or, if you prefer, 24.5 GT. The current deployed US nuclear arsenal conversely has a 1.43 GT total megatonnage, or at least did; it may be even lower now. So while nuclear winter is certainly possible, we'd have to be using a lot more devices. Even at the very height of the cold war there were still collectively at most 65,000 functional nuclear devices in the world, and even if all of them were used their megatonnage would not have amounted to even, at worst, two Tamboras; and that would assume both perfect effectiveness in all weapons, perfect success in use, etc. When in fact that would never by the case, and many were tactical devices or part of stockpiles, or would have been detonated high in the atmosphere, and even airbursts contribute basically nothing to the ejecta required for nuclear winter, nor do they produce substantial fires (they have in fact been used to put out refinery fires before in the USSR), so that only groundbursts that successfully initiated would, by and large, contribute to the problem; broadly speaking, in, short, a nuclear war would have had climatological effects only on the same approximate scale as the eruption of Tambora or a volcano of similar intensity.

[Sky Captain]

How high went the smoke from WWII firebombings? I`d guess it does`t matter much if fire storm is started by nuclear explosion or conventional firebombing. I think the easiest way to clarify effects of nuclear war is to look what happened in known historical firestorms.

During first Gulf war when Iraqis set Kuwait oil wells on fire there were quite a lot of soot spewed into atmosphere and I don`t remember any global environmental effects caused by that.

When Pinatubo went boom it trowed 10 cubic km of dust into atmosphere and reduced global temperatures only about 0.4 - 0.5 degrees. Also large volcanic eruptions are far more energetic than firestorms and throw dust dozens of km high into stratosphere.

IMO for truly devastating global effects to occur you would need something comparable to supervolcanic eruption which is basically multi teraton underground explosion and far more efficient in dust throwing than few thousands of sub megaton airbursts and subsequent fires.
World`s combined nuclear arsenals are something like few dozens of GT which is nothing compared to VEI 8 eruption not to mention that volcanoes produce dust more effectively.

[K. A. Pital]

I think the easiest way to clarify effects of nuclear war is to look what happened in known historical firestorms.

Actually, no, because soot and dust from a nuclear groundburst apparently have a higher potential to reach the stratosphere than firebombing smoke plumes, thus causing a more wide, and lengthy climatic change

I also think that judging by megatonnage is not exactly a fair model, many groundbursts would lift up more soot, while a localized explosion which fails to lift significant amounts into stratosphere will fail to produce long-term climatic effects.

[Sky Captain]

I think the easiest way to clarify effects of nuclear war is to look what happened in known historical firestorms.

Actually, no, because soot and dust from a nuclear groundburst apparently have a higher potential to reach the stratosphere than firebombing smoke plumes, thus causing a more wide, and lengthy climatic change

I also think that judging by megatonnage is not exactly a fair model, many groundbursts would lift up more soot, while a localized explosion which fails to lift significant amounts into stratosphere will fail to produce long-term climatic effects.

I was assuming the dust from explosion itself would be less than than dust and soot produced by burning houses, industrial complexes etc. However explosion would throw dust higher up than mere fires.

Anyway I found starslayer`s article somewhat dubious since it says that nuclear war between India and Pakistan producing 6 - 7 million tons of soot would cause global temperatures to drop by 2 degrees and global nuclear exchange with 180 million tons of soot produced would cause global temperatures to drop by 8 degrees. When in fact recent far more powerful volcanic eruptions producing order of magnitude more dust have failed to catastrophically affect Earth climate.

[K. A. Pital]

I found starslayer`s article somewhat dubious since it says that nuclear war between India and Pakistan producing 6 - 7 million tons of soot would cause global temperatures to drop by 2 degrees and global nuclear exchange with 180 million tons of soot produced would cause global temperatures to drop by 8 degrees. When in fact recent far more powerful volcanic eruptions producing order of magnitude more dust have failed to catastrophically affect Earth climate.

The necessity to shoot the stuff up into the stratosphere is important, far more than sheer megatonnage.

For example, Kuwait smoke plumes were limited in impact, but were they really capable of shooting it up, they'd heavily impact climate all over the world.

[Sky Captain]

I found starslayer`s article somewhat dubious since it says that nuclear war between India and Pakistan producing 6 - 7 million tons of soot would cause global temperatures to drop by 2 degrees and global nuclear exchange with 180 million tons of soot produced would cause global temperatures to drop by 8 degrees. When in fact recent far more powerful volcanic eruptions producing order of magnitude more dust have failed to catastrophically affect Earth climate.

The necessity to shoot the stuff up into the stratosphere is important, far more than sheer megatonnage.

For example, Kuwait smoke plumes were limited in impact, but were they really capable of shooting it up, they'd heavily impact climate all over the world.

Large volcanic eruptions do exactly that - shoot dust high into stratosphere. If we compare volcanic eruption to shallow depth underground nuclear detonation then to replicate relatively minor climatic effect of Tambora we need to groundburst below surface hundreds of Tsar Bomba scale nuclear devices. In realistic nuclear war scenarios no one would use nuclear devices of that magnitude since they are too big and heavy to fit in a rocket and huge overkill for any conceivable target. Sub megaton airbursts over cities would throw little material into stratosphere and most dust would come from resulting fires which probably won`t make into stratosphere.

At least for volcano eruption to have catastrophic climate effect you need eruption of VEI 8 magnitude like Toba eruption throwing few thousand cubic km of dust and hundreds of millions tons of sulphur into atmosphere which is several orders of magnitude more than full scale nuclear war would produce.

[starslayer]

Reading through the article in Physics Today (I'd only really skimmed it before), the authors say that the soot rises to much higher altitudes than the 1980s results according to their new models. This leads to a much longer decay time for atmospheric soot levels, and correspondingly more and longer lasting cooling.

One of their references says that severe ozone depletion results from the smoke plumes. This to me is far more worrying, as plants and animals can survive unseasonal cold for a few years, but would be far more affected by constant increased UV radiation. Most, if not all species would probably still survive, but the result would be even more and harder crop failures if these models prove true.

Large volcanic eruptions do exactly that - shoot dust high into stratosphere. If we compare volcanic eruption to shallow depth underground nuclear detonation then to replicate relatively minor climatic effect of Tambora we need to groundburst below surface hundreds of Tsar Bomba scale nuclear devices.

Remember that although the .7C change resulting from Tambora was relatively "minor," its effects were not. There were snowstorms in New England and the Ohio River Valley in June, which ruined the corn crops, and reduced yields to a mere 10% of normal. Europe had similar problems as well, and this was followed by an unusually harsh winter.

And Duchess and Sky Captain, how are you able to compare volcanic eruptions (large, single, localized events) to many scattered detonations? We may need a buried nuke larger than everything we have ever built combined to recreate something like Tambora, but what of the potential effects of many separate ground or airbursts that may have similar combined effects, even if the sheer megatonnage is not equivalent? We are, after all, discussing the effects of smoke plumes, large, persistent entities that may be burning for many days or weeks, releasing far more soot than the explosions themselves. How much of the Tamboran ash cloud fell to Earth relatively quickly (week or two), and how much hit the stratosphere? According to these papers, only 20% of the soot from the fires would rain out or otherwise fall before reaching the stratosphere.

A couple notes: Duchess, the Russians used nukes to put out refinery fires? Sources? I know that dynamite will put out oil well fires that have already been lit, but we're talking about the nukes being dropped on targets that are not presently on fire, and the resulting large explosions and thermal pulses setting them. How large were the fires at Hiroshima and Nagasaki after the bombings? How long did they burn? If they were actively fought, how long would they have burned had they not been fought?

I also found this paper to be very informative and detailed.

[The Duchess of Zeon]

First thing's first, most nuclear events would not inject any appreciable quantities of dust into the atmosphere to begin with. Where would the dust be collected from? The answer is nowhere; the fireball must touch the ground and thus vapourize large quantities of matter into particulate form for injection into the upper atmosphere; the ignition of major fires can be studied already today, for instance in Indonesia, and we do not need models to do this for us, we have empirical data now from these huge out of control fires which have recently existed in that region, which can instead be expanded for a large area of effect to correctly judge the amount of high atmosphere injection by the secondary fires, so one wonders why this group, and what their motives are, for returning to a model in the 1980s and modifying its data, instead of developing a model based on recent events which provide actual empirical data? So we'll look at Indonesia--I will shortly--to make some considerations in this regard. But of course only groundbursts will injection particulate matter into the atmosphere, and only a relatively small percentage of nuclear events would be groundbursts, which must also be accounted for.

And this is why Tambora is relevant, Starslayer. Because the force of the detonation lends more power for thrusting more material into the stratosphere Even a twenty megatonne groundburst after all will inject only a small fraction of material into the upper atmosphere, because it lacks the power in one place to force up more... Now as these dust clouds spread around the world we will quickly see mitigation, in the volcanic event, due to the interchange of the atmosphere at high levels, a fairly even cloud will develop not all that different from having a large number of smaller events. Only in the short duration after the initial events is there a major difference. So first of all we're going to see only a small portion of the nuclear devices actually inject particulate matter into the atmosphere, in comparison with a volcano like Tambora which has the ability to lift millions of tonnes or hundreds of millions of tonnes of debris into the high atmosphere!

As for the fact that nuclear airbursts can in fact be used to extinguish fires, I was, apologies, slightly wrong; they were not refinery fires, but gas well fires, as seen here:

[In] November of 1965, a conference was held in the Soviet Union to consider
possible industrial and scientific uses for nuclear explosions. The meeting included
the leading scientists and weapons designers in the Soviet nuclear weapons program,
including Andrei Sakharov. The scientists evinced great interest in such a program,
including the development of special explosives to facilitate the fielding of nuclear
explosives in unique industrial situations and to reduce the radioactivity produced by
such explosions. The ideas discussed ranged from scientific experiments and
industrial applications utilizing the unique physical and electromagnetic properties
of nuclear explosions to controlling asteroids and powering rockets in deep space.16
In the middle of 1966, a crisis in the gas industry suddenly offered an
opportunity for a new application for peaceful nuclear explosions, the extinguishing
of runaway gas wells. Successfully closing several such wells in 1966 and 1967 gave
growing confidence to the leaders of the program and they began to think about a
broad spectrum of new applications

This reference being from Page twelve of this article.


Now, as for the Indonesian fires, these released 2.6 billion tonnes of carbon into the atmosphere! -- Mostly in the form of carbon dioxide! -- which is of course a greenhouse gas, and that these fires released, thus, about as much carbon dioxide into the atmosphere as the entire Earth sequesters in an entire year. Now this is why the idea that the vast fires ignited by a nuclear war would cause a nuclear winter is very, very silly--they are actually injecting greenhouse gasses which would warm the planet, and thus counterbalance the effect of high atmospheric injection of particulate matter from the events themselves. Now certainly the clouds of soot will initially make things much colder--nobody is disputing this, and since the northern regions are peatlands just like 730,000 hectares of peatlands out of 800,000 hectares that burned during the Indonesian fires, these comparisons will nonetheless hold up well, but overall: as we seem from similar fires in 2006, this matter only remained in the atmosphere for several weeks.

Therefore, this "study" seems to ignore all existing empirical data, which is that,

A majority of nuclear initiations will be airbursts which by definition cannot inject particulate matter into the high atmosphere in any quantity, that quantities injected from groundbursts will be substantially less than those from eruptions of major stratovolcanoes, that high atmospheric winds quickly spread ejecta from stratovolcanoes across the globe, so that different concentrations between a volcano and a nuclear war will only exist for a period of weeks or months, and that empirical data from vast, 800,000 hectare fires, including 730,000 hectares of peat, in short, similar organic material to the proposed vast fires in the northern wildernesses of Canada, the United States, and the Soviet Union in a nuclear war, indicates that all of the soot clouds remained in the atmosphere only for several weeks, whereas the gasses which cause global warming would be the permanent ones, and of course that Carbon Dioxide is the main global warming gas being released here, and that does NOT harm the ozone layer.

Now, with all of this considered, it is I believe contingent upon you to prove that "nuclear winter" could actually threaten life on Earth through some unknown mechanism, since the only two mechanisms in a nuclear exchange for causing a "nuclear winter", high atmospheric injection of particulate matter by fireballs of ground-contact nuclear initiations in the primus, and in the secundus, soot release from fires initated as secondary effects of nuclear initiations (which clearly since airbursts can actually extinguish fires may be of a quite limited effect), have been proved to be insufficient to cause a more serious event than Tambora to the Earth, and in fact that Tambora was eminently survivable by all life on the planet, just a severe hardship.

So now the onus is on you to explain this hidden third mechanism which will somehow put enough particulate matter into the high atmosphere to cause a nuclear winter which will be the extinction of most life on Earth, since according to all available data no such mechanism actually exists. (If you were just asking for clarification, I apologize, but this matter must be aggressively addressed because some very educated people otherwise behave like idiots when the subject of Nuclear Winter comes up, and therefore the subject must be very aggressively addressed and these people who are mostly reasonable must be either forced to see reason, or else demonstrated to be doctoring figures and arguments as part of a political agenda).

[JointStrikeFighter]

(they have in fact been used to put out refinery fires before in the USSR),

WHOAH WHOAH WHOAH WHAT!?

[The Duchess of Zeon]

(they have in fact been used to put out refinery fires before in the USSR),

WHOAH WHOAH WHOAH WHAT!?

See the post above you--I slightly misremembered, but nuclear devices were in fact actually used in the USSR in 1966 and 1967 to extinguish gas well fires.

[JointStrikeFighter]

(they have in fact been used to put out refinery fires before in the USSR),

WHOAH WHOAH WHOAH WHAT!?

See the post above you--I slightly misremembered, but nuclear devices were in fact actually used in the USSR in 1966 and 1967 to extinguish gas well fires.

Do you have any more information?

[The Duchess of Zeon]

Do you have any more information?

Yeah, here's another source.

As you can see the Soviets did a fairly extensive amount of testing and also actual employment of nuclear devices for non-warfare purposes.

Ah, and a couple more general sources on Soviet peaceful nuclear events:

There's a Russian source

And An America Source.

Note that the actual number of uncontrollable fires extinguished by Soviet nuclear events may have been as high as six according to some reports--five were natural gas wells, one a methane blowout or something of that sort.

[Adrian Laguna]

The United States also researched the peaceful use of nuclear devices in the 60s. I am very short on time and cannot site any sources, but anyone interested should look up Project Plowshare. From what I remember, atomics were considered for mining, massive earth moving, creating artificial harbours, and cooking oil shale for extraction.

[Sky Captain]

but this matter must be aggressively addressed because some very educated people otherwise behave like idiots when the subject of Nuclear Winter comes up, and therefore the subject must be very aggressively addressed and these people who are mostly reasonable must be either forced to see reason, or else demonstrated to be doctoring figures and arguments as part of a political agenda).

Well, I have came across otherwise reasonable people who think US and Russia has enough nuclear devices to not only exterminate all life, but knock Earth out of orbit or even blow into asteroid field.

[Ma Deuce]

Anyway I found starslayer`s article somewhat dubious since it says that nuclear war between India and Pakistan producing 6 - 7 million tons of soot would cause global temperatures to drop by 2 degrees and global nuclear exchange with 180 million tons of soot produced would cause global temperatures to drop by 8 degrees. When in fact recent far more powerful volcanic eruptions producing order of magnitude more dust have failed to catastrophically affect Earth climate.

Wait what? They're seriously trying to claim that an exchange between India and Pakistan would produce noticeable global climate cooling, when the 500+ atmospheric tests in the 50s and 60s failed to do so? Now, granted those tests were spread out over a decade or so, but the devices used were on average, far more powerful than what India and Pakistan currently possess.

[Ma Deuce]

Ghetto edit: I also notice that two of the names on that paper (Turco and Toon) were also two of the authors of the TTAPS study. That alone should cast doubt on it's credibility.

BTW, where's Stuart? It was his essays which (for me at least) demolished TTAPS in detail, and I'd love to see him weigh in on these more recent studies.

[Sky Captain]

Anyway I found starslayer`s article somewhat dubious since it says that nuclear war between India and Pakistan producing 6 - 7 million tons of soot would cause global temperatures to drop by 2 degrees and global nuclear exchange with 180 million tons of soot produced would cause global temperatures to drop by 8 degrees. When in fact recent far more powerful volcanic eruptions producing order of magnitude more dust have failed to catastrophically affect Earth climate.

Wait what? They're seriously trying to claim that an exchange between India and Pakistan would produce noticeable global climate cooling, when the 500+ atmospheric tests in the 50s and 60s failed to do so? Now, granted those tests were spread out over a decade or so, but the devices used were on average, far more powerful than what India and Pakistan currently possess.

Yeah that`s what they are claiming. They are assuming soot spewed out by fires started by 100 nuclear bombs airbursting over Indian and Pakistan cities would cause more cooling than Tambora eruption which ejected several orders of magnitude more dust up to 40 km height.

Basically they are claiming most of the dust will came from fires not from nuclear fireball touching ground, completely ignoring the fact that known large scale forest fires have failed to produce measurable global cooling.

[The Duchess of Zeon]

Considering that's basically three orders of magnitude less than the amount of carbon alone (they released other junk) that the Indonesian fires released into the atmosphere, that should tell you that the study in question is worthless, a pure propaganda piece intended only to terrify people, for their own aims. Science studies which go directly contrary to observed reality either have a very good reason for it... Or a very political reason for it.

[starslayer]

Thank you for the additional information, Duchess. I'm not a climatologist by trade, nor am I involved in the nuclear business (though I am interested in both subjects). All I was trying to do was ask some questions, for I readily admit my knowledge in this area is limited, and there seemed to be conflicting information. I now realize that this is not the case. Since Turco and Toon were involved in the TTAPS study, that does indeed cast doubt on the credibility of their work. I am not trying to prove that nuclear winter exists; when I first read the articles, I felt that it may have presented a new or more compelling case (from reading this board in the past, I knew that TTAPS was bunk). From your analysis, I must conclude that the authors are quite wrong in their estimation of the long-term threat posed by a nuclear war.