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Climate Hustle

How much has nuclear testing contributed to global warming?

Posted on 24 August 2012 by Tom Curtis

A reasonable estimate indicates that the total energy released by nuclear explosions in the twentieth century amounts to six hundred megatons TNT equivalent of energy, or 2.5 billion, billion Joules (2.5 x 1018 J).  That estimate  is larger than the five hundred and thirty megatons TNT equivalent estimated by UNSCEAR (also), so it can be considered a conservative estimate.  Divided over the five hundred and ten million, million square meters of the Earth's surface (510 x 1012 m^2), and over the two decades of peak testing, that represents eight millionth of a Watt per square meter (8 x 10-6 W m-2) of power.  For comparison, the 1.8 Watts per square meter (1.8 W m-2) of CO2 radiative forcing as of 2011 generates approximately twenty nine billion, trillion Joules of energy (29 x 1021 J) over the Earth's surface in a single year, or more than ten thousand times as much energy in a year that the entire combined nuclear weapons program of the world has generated.

That is not the whole story.  Many nuclear tests kick up a lot of dust, which reflects sunlight, thereby cooling the Earth.  Indeed, according to Turco et al, 1983, that is the dominant effect of nuclear explosions on climate.  The result is that nuclear testing is likely to have reflected more energy from the Sun than they generated.  That is, nuclear testing is likely to have been a net cooling factor.

Let us ignore that possibility, and the large proportion of energy released to space as radiation.  In that case, during the period of maximum nuclear testing it may have contributed 0.62 millionth of a degree Centigrade (0.62 x 10-6 C) to temperature increase, a contribution too small to notice, and likely to have entirely dissipated since the reduction in nuclear testing in the 1990s.  The peak contribution was in 1962, when nuclear testing may have contributed as much as one hundred and seventy megatons TNT equivalent of energy in 1962.  Averaged over the year and the Earth's surface, that represents forty-four millionths of a Watt (44 x 10-6 W m-2), for a warming contribution, ignoring dust effects, of around thirty-five millionths of a degree Centigrade (35 * 10-6  C), still too small to notice.



Note: this is the intermediate rebuttal to 'nuclear testing is causing global warming' and can be found at the short URL

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Comments 1 to 32:

  1. I thought I was familiar with pretty much all the myriad loopy dissenting arguments. This one took me by surprise.

    There are some very important historical links between nuclear weapons and climate science, since the rapid improvement in atmospheric monitoring and modelling that occurred after WWII was very significantly driven by the desire to learn more about the likely fallout distribution of nuclear explosions. I read a fascinating article drawing many of these links, though can't find it right now.
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  2. Byron: I thought I was familiar with pretty much all the myriad loopy dissenting arguments.

    Me too. There are a lot of problems with this idea beyond the basic erg deficit. I don't think nuclear weapons release a new form of energy that is unusually subject to gravitational attraction, weapons testing largely ended a long time ago, yet the energy released in those tests is supposed to be lingering? How?

    Is a bizarre argument like this a sign of hope or cause for depression? Desperate hail Mary or indicator of a receptive audience whose thinking skills have collapsed and dribbled away like ice cream on a a hot summer day?
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  3. I certainly can't recall seeing anyone make this claim before online.
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  4. Tom Curtis, in your third 'graph, under the "Annual Yields" graph, you've mispelled 'from' to 'form.'

    I understand though, having rented flingers, too..;)

    Thanks for this article, and to Doug: I'm waiting for bated breath to hear what next the denialisti come up with, for the global warmings, as their cherished 'causes' fall like dominos.

    Excessive planting of sunflowers, causing too much reflection of yellow light up to the troposphere?

    Where I live--surrounded by ~25K acres of corn, alfalfa, and *sunflowers*, and in the county in which I live (where I'm one of two, *maybe* ten Progressives--it would be an easy sell.

    You heard it here, first...;(
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  5. On a more serious note, have a look at the discussion in Fujii 2011, on stagnation of Global Warming in mid 20th Century. Interesting read, and more of a case for cooling due to atmospheric nuclear explosions than warming
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    Moderator Response: [DB] Fixed link.
  6. Byron et al. "I thought I was familiar with pretty much all the myriad loopy dissenting arguments. This one took me by surprise."

    I'll bet you don't know this one either.
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  7. Like the sheep.

    The world sheep population has fallen by 1% since 1992.

    They'll be paying farmers to breed pale coloured animals next.

    Wouldn't want to be black sheep.
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  8. Fujii link now fixed, apologies. I see Watts criticised it last year, so maybe there's merit to it.
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  9. vroomie @4, thanks, and fixed.

    Byron Smith @1, this is certainly not the loopiest idea I have ever seen from AGW "skeptics". The most bizarre is the idea that it is radar that is causing global warming. The next most bizarre is that not only is geothermal energy causing global warming, but the relatively temperate climate at the Earth's surface is entirely caused by geothermal energy.

    The theory that nuclear weapons is the cause involves primarily a simple failure to grasp the scale of the energies involved. Consequently it will have an intuitive appeal to the scientifically uninformed; but fortunately only to a very few on the sidelines.
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  10. Tom@9: HAARP.

    Oh, and the evil gummint contrails...
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  11. I'm dubbing it HAARP's Law (the equivalent of Godwin's Law):
    1. As an online discussion grows longer, the probability of a comparison involving HAARP and/or jet contrails/chemtrails/new world order (nwo) approaches 1.

    2. In other words, given enough time, in any online discussion—regardless of topic or scope—someone inevitably makes a comparison to HAARP and/or jet contrails/chemtrails/nwo.

    3. Once such a comparison is made, the thread is finished and whoever mentioned the HAARP and/or jet contrails/chemtrails/nwo has automatically lost whatever debate was in progress.
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  12. When flying in comment streams, don't poke the HAARPies!
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  13. I was going to suggest that we shouldn't haarp on about this... ;-)
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  14. "Chemtrails," not contrails!

    How can we enact a conspiracy if we can't keep our terms straight?

    No "Agenda 21 Decoder Ring" for you guys, sorry.
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  15. Looking of nuke test influence over the climate is a joke, however a related topic: the natural radioactive decay in Earth's mantle is not.

    This wikipedia article provides the real, somewhat signifficant number of 0.1W/m2 as the geo-radiative heat escaping to space currently. It used to be twice higher 2Ga. So, some (within just one order of magnitude-10) portion of this heat, diminishing as the Earth ages, can be attriubuted for recent cooling from hothouse of ancient history. I cannot find any more info about that in climate studies that I've looked at, which IMO cannot be ignored, because 0.1W/m2 should be taken into account if taking about total radiative balance. Or, maybe less geo-heat in recent times can mean that simply plate techtonics are not as fast as they used to be with no change to radiative balance, hopefully some geologist would explain it to me? Thanks.
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  16. I once had to debunk a similar thing: that time it was microwave radiation. As in the calculation above, the estimation (in favor of the hypothesis by overestimating sender density and strength and handy strength and usage) showed a difference of several orders of magnitude compared to the energy needed to heat the globe as is observed.
    Some arguments can easily be checked ad hoc for validity, but the more advanced biasing, tweaking, cherry picking, falsifying, etc. of science is not so easy to get for me - despite my regular reading on climate here and elsewhere - and I am very thankful to all people here contributing to this fact oriented work. I personally am not a (semi-)professional on the subject, so I only con contribute a little money to the web site each year: one of the best investments I can make in a livable future, I think.
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  17. DB@11: I *like* it!

    Now, who's gonna write it up on Wikipedia? The birth of a new definition is something I'm not sure I've ever witnessed, before!
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  18. #5 Peter - agreed.

    The Role of Atmospheric Nuclear Explosions on the tagnation of Global Warming in the Mid 20th Century
    Yoshiaki Fujii

    This study suggests that the cause of the stagnation in global warming in the mid 20th century was the atmospheric nuclear explosions detonated between 1945 and 1980. The estimated GST drop due to fine dust from the actual atmospheric nuclear explosions based on the published simulation results by other researchers (a single column model and Atmosphere-Ocean General Circulation Model) has served to explain the stagnation in global warming. Atmospheric nuclear explosions can be regarded as full-scale in situ tests for nuclear winter. The non-negligible amount of GST drop from the actual atmospheric explosions suggests that nuclear winter is not just a theory but has actually occurred, albeit on a small scale. The accuracy of the simulations of GST by IPCC would also be improved significantly by introducing the influence of fine dust from the actual atmospheric nuclear explosions into their climate models; thus, global warming behavior could be more accurately predicted.

    So atmospheric tests inject aerosols into the stratosphere like a thousand mini-volcanoes.
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  19. I would have thought that the amount of organic material vaporised by nuclear explosions would be more significant than energy released, as it would all convert to CO2. This would still be small on a global scale.
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  20. [Snipped of topic comments]
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    Moderator Response: TC: jmorpuss, Skeptical Science does not exist for your benefit, and nor do you have a special privilege to ignore the comments policy. If you wish to discuss the absurd theory that microwave transmissions cause global warming, you are entitled to do so where it is on topic, and not anywhere else.

    Please carefully peruse the comments policy before commenting there as well. If you do not have anything new to add to what you have already written, as appears to be the case, simply regurgitating the same tires arguments will result in your posts being deleted for failing to avoid excessive repetition, and sloganeering.
  21. I found the answer to my post @15 and pointers to the interesting papers on another thread:

    SkS is an excellent source of knowledge if you know how to search it...
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    Moderator Response: TC: Link made live.
  22. Where did this Einstinean idea originate from? I give our Lord Monckton the benefit of a doubt - I can't believe he'll stoop that low. Then again...
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  23. TC, ModComm@20....what?? Now there's a "tires cause GW" argument?

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    Moderator Response: TC: I meant "tired", of course, and as you obviously realize. I shall allow the misprint to stand so that your joke can as well. (It is not often I get to start my GW reading in the morning with a chuckle.)
  24. Well, vroomie, I don't think that argument's going to get any traction. I mean, evidence is where the rubber hits the road. It's been a good year for GW, and we're rapidly turning the planet into a fire stone.

    This tread is kind of petering out, isn't it?
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  25. DSL@24:......*ow*.

    But, you're right; this t(h)read is becoming kinda like a carcass....;)

    TC: I aims ta please! I'm a big believer in humor, both remaining in a tough topic, and being injected into ones that are bordering on war--not that this one was--but I am glad you got the joke!
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  26. Please my ignorance, but the way it was described to me many years ago in high school, dropping an h-bomb was equal to taking a teaspoon of the sun and exposing it to Earth's atmosphere.  Is there any way someone might describe the thermal change caused by above  ground testing in terms of heat from automobiles or dmage done by coal emissions?

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  27. earthhouse

    As a comparison, a common unit that is being used to describe the amount of heat accumulating in the worlds oceans, where over 90% of the heat is going, is the Hiro. The Energy of 1 Hiroshima bomb. Energy is accumulating in the oceans at around 4 Hiro's per second. The very largest bombs ever exploded were of the order of a 1000 times larger than the Hiroshima bomb but only a tiny number of those were ever tested. quite a few bombs that were 10 to 100 times larger than the Hiroshima bomb were tested. Possibly hundreds.

    Wikipedia suggests there have been nearly 2000 tests.

    So lets say as an upper limit that there were 2000 tests at 100 times the size of the Hiroshima bomb.  200,000 Hiro's. That is the equivalent of just under 14 hours worth of heat accumulation in the oceans. So totally insignificant compared to the heating being observed.

    It can be hard to get our heads around the relative magnitudes of different very large quantities.

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  28. earthhouse @26, that is an interesting analogy.

    Assuming that all energy from nuclear tests was dissipated as heat in the Earth's atmosphere (which without doubt over estimates the amount of heat generated), 0.000044 W/m^2 of energy was generated over the years of nuclear testing.  For comparison, the total waste heat from human industry, power generation and transport is 0.028 W/m^2, or 636 times as much.  The current Top Of Atmosphere (TOA) energy imbalance is approximately 0.6 W/m^2, or 13,636 as much.  The current forcing by CO2 is 1.9 W/m^2, or 43,368 times as much.

    Comparison with the power output of individual cars could, no doubt, be calculated, but I do not think the result would be informative.  However, the total energy released by nuclear testing (2.5 x 10^18 Joules) is equivalent to that which would be released by burning 71.4 billion liters of gasoline, or 18.9 billion gallons.   However, actually burning that amount of gasoline would release 164 million tonnes of CO2, which as it happens is a mere 0.012 ppmv of atmospheric content, considering only the portion retained in the atmosphere.  The additional greenhouse effect of that tiny amount of additional CO2 would be 0.00016 W/m^2, or 3.6 times the amount from the total energy release from nuclear testing, with the difference being that that increased greenhouse effect would continue year on year, while the nuclear testing is over and done, and it forcing along with it.

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  29. Glenn @27, as you know I strenuously object to the use of the "Hiro" as a unit of energy, both because (as I understand it), the residents of Hiroshima find it offensive, and because its impact factor comes from its association with the explosion of Little Boy at Hiroshima, with the deaths of 100,000 people immediately or from injuries recieved, and further deaths of 100,000 people +/-  from radiation exposure.

    I also consider it a scientifically limited comparitor with the total forcing or TOA energy imbalance because it leaves out the essential factor of entropy.  The energy imbalance due to the greenhouse effect is not like the dropping of four atomic bombs a second at random over the Earth's surface because far less destructive (while noting that the much less destructive effects will also be much longer lasting, and indeed will outlast the energy imbalance itself). 

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  30. I read somewhere that the dust from nuclear testing might have had a cooling affect from increased albeido.  Does anyone know if that is real or just something that is spread on the internet?

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  31. Google finds this article, unfortunately behind a pay wall.  The abstract claims that the global temperature hiatus from 1950-1970 can be attributed to fine dust from above ground nuclear tests.  Very few cites by scientists so apparently other scientists did not think much of the hypothesis. 

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  32. michael sweet @30, based on Turco et al that would have been the dominant impact of nuclear testing on climate.  I believe Turco et al over estimated the impact of nuclear exchanges on climate, primarilly by underestimating the moderating effect of the thermal mass of the oceans.  Further, many nuclear tests were underground (eliminating the aerosol forcing) or at sea (minimizing it), so it is not certain that he net forcing would have been negative, though still likely.   However the effect in either direction would be far to small to distinguish from the impact of other factors on Earth's short term climate in the fifties and sixties.

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