How many kilotons should we expect per kilogram? This article is great in answering that: https://blog.nuclearsecrecy.com/2013/12/23/kilotons-per-kilogram/ "all US weapons currently in the stockpile end up, in the 0.1-3 kt/kg range, especially the 2-3 kt/kg range" So only if we use the absolutely lowest values of this ratio and the lower end of the payload estimate, we will get 250 kilotons, but as some of the nuclear weapons in the US nuclear stockpile were developed in the late 1960s and 1970s https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html and with the possibility of Russia sharing their nuclear know how along with some other technical expertise with North Korea in exchange for weapons and soldiers, I am not an expert, but I think we can expect that they will be able to achieve better kiloton to kg ratio than 0.1 kiloton/kg. So I think they aim for something bigger than 250 kilotons, especially now, when they may have access to Russian expertise. I may be wrong, since my understanding is limited, but I think they are now likely working on some new design with higher yield, rather than only making more of the current ones. Another point: other pros were right to point out that the warnings about the test keep repeating and nothing happens. However, as I read some of the warnings from last two years, one (IIRC it was from 2022) was saying explicitly that the test is not imminent but that North Korea is working on the technology and the test is likely in the future, and the one from 2023 said about the test "next year", So maybe some of these were not necessary false alarms, or at least we do not know yet. One more point that comes to my mind: I love the idea that we would be able to see preparations for the test on the satellite images so if we cannot see them now it will likely not happen in the next two or three months, but I keep thinking - if North Korea is determined to conduct the test (they may want to test improvements, especially if there is/will be know-how transfer from Russia - I assume that they will want to test it, that testing is needed for new designs or at least they will want it to be sure) they may want to try hiding the preparations for the test and avoid international pressure not to do it (I would expect pressure if everyone could read about the preparations). Is it possible? It would be hard, but India was successful. Also, the problem with any open-source intelligence methods which results are published online is that the people whom we observe can access these analyses as well and they will know what to hide from us. As a counter-argument, it is one thing to play this tactic with the West, but they also have to think about their relationship with China, which is against North Korean nuclear tests.
I think the probability slightly increases over time because this is a process that is progressing, and now they may have Russian help. At the same time, I don't think they will do the test that fast. Of course, I may underestimate the importance of political factors here, like nuclear diplomacy with the new US President for example - if Kim Jong Un decide that it may give him political benefits, then testing even the same nuclear bomb as before would be reasonable.
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Why might you be wrong?
I wonder if North Korean government affiliated forecasters were asked what would be a result of conducting a nuclear test before the US Elections on their result... This is not impossible.
I think the question needs to be divided into two parts for probability assessment. Part one is technical which you provide a lot of good information for. A couple things I would add. If we look at the previous 6 tests we can see a significant increase in the last one (Richter around 6.0). Most analysis at the time and since has said this was a thermonuclear or better to understand maybe as a two-stage device. So the question becomes, if it was a two-stage device what further testing is needed? https://missilethreat.csis.org/north-korea-missile-launches-1984-present/
You mention that 250 kiloton is a threshold for consideration. I would offer most of the world's 2 stage missile delivered weapons fall into the hundreds of kilotons range. Not necessarily for destructive power, but mostly for payload considerations. It takes more and more missile to launch extra weight. Scrolling through the choices of all weapons on NukeMap shows very large weapons are less and less likely in today's world.
The second part is to ask the political messaging of the statement. While not a tight correlation, I think you can see some in the months and years of launches relative to US elections in the wikipedia cataloguing of launches. Particularly if there is a change in political parties. Some would argue Kim tries to press new administrations to test if policies and postures are going to change. https://en.wikipedia.org/wiki/List_of_North_Korean_missile_tests
@NukePirate thank you very much for your prompt feedback and giving me food for thought. I know my logic about their missile payload suggesting being intended for a larger warhead was based on estimates and if the estimates are wrong, the conclusion may easily be wrong (not true). Good point with: "Most analysis at the time and since has said this was a thermonuclear or better to understand maybe as a two-stage device. So the question becomes, if it was a two-stage device, what further testing is needed?" This is similar to one of my technical questions - is the test needed for a bigger bomb. I assume you know more on these stuff than most forecasters here (more than myself for sure), but even collecting our collective educated-guesses about the technical stuff the wisdom of crowd will only return wisdom if the average participant is at least slightly more likely to guess right than not. It would be super useful to have a call with a RAND expert on that matter or at least deliver a few technical questions to them in the written form by our managers at RFI/CL. @FP - do you think someone from RAND from that field could be willing to share some of their wisdom? The last call with the SME was great, even just something like a reply from SME to questions sent in the email should be very useful.
@srl I noticed your high quality forecasting rationales and followed you. Back then I also noticed in your description that you are a physicist, and as I just checked, you are a nuclear physicist, right? I do not know if you are affiliated with RAND, and even if you are, I don't have any power to ask you for help as a part of your work, but I wanted to ask: Would you be interested in sharing some of your technical expertise with us?
I collected some statements from my own forecast (above) and other forecasters comments to collect our pro forecasters educated guesses (or in some cases, answers based on some level of expertise rather than guesses), but I thought that with technical questions you may be able to answer more like "yes" or "no" or "it depends on..." Here is my judgmental poll:https://forms.gle/RGEmDAmBxVet8xE46 Results will be visible here: https://docs.google.com/spreadsheets/d/1WtzZ58z-Fb8OBOJidJDJpSngIyYgy5sAt_CnbrIHg44/edit?usp=sharing Here is my list of statements to be assessed (they are not necessary my own views - I highlighted the technical questions with bold but if you are interested, feel free to answer any of them): The kiloton-to-kilogram efficiency of North Korea’s nuclear warheads is likely comparable to US weapons developed in the 1960s and 1970s (0.1-3 kt/kg) - (that was my guess) my friend @geoffodlum suggests that their designs may rather be comparable to US designs in the 1970's or early 1980s Russian expertise is enhancing North Korea’s nuclear weapons development, including yield and design improvements. New designs of nuclear weapons require testing to ensure reliability and performance. North Korea is working on a new nuclear design with a yield higher than 250 kilotons. Russian support is accelerating North Korea’s progress in nuclear development. China really (not just officially) wants North Korea to refrain from conducting any further nuclear tests. North Korea is determined to conduct another nuclear test at some point in the future. Past warnings about nuclear tests were not necessarily false alarms but reflect a gradual development process. China would impose significant pressure on North Korea if test preparations were discovered. North Korea could successfuly use techniques similar to India’s to conceal nuclear test preparations from international observation, including from China and the US. North Korea’s current geopolitical strategy makes a nuclear test within the next six months advantageous from their perspective North Korea is working on new nuclear weapon designs. The probability of a nuclear test increases over time. North Korea relies heavily on its nuclear program to maintain international relevance. North Korea is in a stronger position now due to support from Russia and China, reducing the need for saber-rattling. The absence of visible test site activity, a reliable indicator of no imminent test. In the short term (at least 6 months) North Korea will focus on missile launches or other provocations rather than nuclear tests. North Korea’s collaboration with Russia makes a nuclear test less likely in the short term (at least 6 months).
If this request from me would disturb your work in any way, please ignore it.
Why do you think you're right?
I start with 18%, I read some really great comments by other pros. Some ideas that came to my mind:
I read a good argument that they may not need testing since they already tested their nuclear bombs in the past and have something that works. In the last test in 2017 the blast was estimated to be around 250 kilotons. How much is it? For the purpose of calibrating our mental models we can use:https://nuclearsecrecy.com/nukemap/ If this will not be too disturbing for you, you can see the blast area for such a nuclear detonation in some cities which you know from your experience (have a mental representation of their size). Examples:
Washington DC: https://nuclearsecrecy.com/nukemap/?&kt=250&lat=38.895037&lng=-77.036543&airburst=0&hob_ft=0&psi=20,5,1&zm=12
London: https://nuclearsecrecy.com/nukemap/?&kt=250&lat=51.5073219&lng=-0.1276474&airburst=0&hob_ft=0&psi=20,5,1&zm=11
Seoul: https://nuclearsecrecy.com/nukemap/?&kt=250&lat=37.5666791&lng=126.9782914&airburst=0&hob_ft=0&psi=20,5,1&zm=12
Warsaw: https://nuclearsecrecy.com/nukemap/?&kt=250&lat=52.231958&lng=21.006725&airburst=0&hob_ft=0&psi=20,5,1&zm=11
Can we look at North Korean Ballistic Missiles payload capabilities to say something about warheads they intend to carry on them? 38North have estimated payload of North Korean Hwasong-16 ballistic missile payload to be about 2,500 to 3,000 kg,
How many kilotons should we expect per kilogram? This article is great in answering that:
https://blog.nuclearsecrecy.com/2013/12/23/kilotons-per-kilogram/
"all US weapons currently in the stockpile end up, in the 0.1-3 kt/kg range, especially the 2-3 kt/kg range"
So only if we use the absolutely lowest values of this ratio and the lower end of the payload estimate, we will get 250 kilotons, but as some of the nuclear weapons in the US nuclear stockpile were developed in the late 1960s and 1970s https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html and with the possibility of Russia sharing their nuclear know how along with some other technical expertise with North Korea in exchange for weapons and soldiers, I am not an expert, but I think we can expect that they will be able to achieve better kiloton to kg ratio than 0.1 kiloton/kg. So I think they aim for something bigger than 250 kilotons, especially now, when they may have access to Russian expertise. I may be wrong, since my understanding is limited, but I think they are now likely working on some new design with higher yield, rather than only making more of the current ones.
Another point: other pros were right to point out that the warnings about the test keep repeating and nothing happens. However, as I read some of the warnings from last two years, one (IIRC it was from 2022) was saying explicitly that the test is not imminent but that North Korea is working on the technology and the test is likely in the future, and the one from 2023 said about the test "next year", So maybe some of these were not necessary false alarms, or at least we do not know yet.
One more point that comes to my mind: I love the idea that we would be able to see preparations for the test on the satellite images so if we cannot see them now it will likely not happen in the next two or three months, but I keep thinking - if North Korea is determined to conduct the test (they may want to test improvements, especially if there is/will be know-how transfer from Russia - I assume that they will want to test it, that testing is needed for new designs or at least they will want it to be sure) they may want to try hiding the preparations for the test and avoid international pressure not to do it (I would expect pressure if everyone could read about the preparations). Is it possible? It would be hard, but India was successful. Also, the problem with any open-source intelligence methods which results are published online is that the people whom we observe can access these analyses as well and they will know what to hide from us. As a counter-argument, it is one thing to play this tactic with the West, but they also have to think about their relationship with China, which is against North Korean nuclear tests.
I think the probability slightly increases over time because this is a process that is progressing, and now they may have Russian help. At the same time, I don't think they will do the test that fast. Of course, I may underestimate the importance of political factors here, like nuclear diplomacy with the new US President for example - if Kim Jong Un decide that it may give him political benefits, then testing even the same nuclear bomb as before would be reasonable.
Why might you be wrong?
I wonder if North Korean government affiliated forecasters were asked what would be a result of conducting a nuclear test before the US Elections on their result... This is not impossible.
I think the question needs to be divided into two parts for probability assessment.
Part one is technical which you provide a lot of good information for. A couple things I would add. If we look at the previous 6 tests we can see a significant increase in the last one (Richter around 6.0). Most analysis at the time and since has said this was a thermonuclear or better to understand maybe as a two-stage device. So the question becomes, if it was a two-stage device what further testing is needed?
https://missilethreat.csis.org/north-korea-missile-launches-1984-present/
You mention that 250 kiloton is a threshold for consideration. I would offer most of the world's 2 stage missile delivered weapons fall into the hundreds of kilotons range. Not necessarily for destructive power, but mostly for payload considerations. It takes more and more missile to launch extra weight. Scrolling through the choices of all weapons on NukeMap shows very large weapons are less and less likely in today's world.
Of course there are reports that the testing site was destroyed in the 2017 test. So the question becomes have they had enough time to rebuild the site for another test. Or would they choose another site. And why.
https://www.nti.org/education-center/facilities/punggye-ri-nuclear-test-facility/
The second part is to ask the political messaging of the statement. While not a tight correlation, I think you can see some in the months and years of launches relative to US elections in the wikipedia cataloguing of launches. Particularly if there is a change in political parties. Some would argue Kim tries to press new administrations to test if policies and postures are going to change.
https://en.wikipedia.org/wiki/List_of_North_Korean_missile_tests
While this isn't comprehensive, it's a relatively good laydown of the considerations surrounding North Korea's nuclear program.
https://www.csis.org/analysis/dprk-aggression-near-term-concerns-longer-term-challenges
Overall, I'm not currenting forecasting on this question but probably should be. Thanks for the prompt.
@michal_dubrawski
I collected some statements from my own forecast (above) and other forecasters comments to collect our pro forecasters educated guesses (or in some cases, answers based on some level of expertise rather than guesses), but I thought that with technical questions you may be able to answer more like "yes" or "no" or "it depends on..." Here is my judgmental poll:https://forms.gle/RGEmDAmBxVet8xE46
Results will be visible here: https://docs.google.com/spreadsheets/d/1WtzZ58z-Fb8OBOJidJDJpSngIyYgy5sAt_CnbrIHg44/edit?usp=sharing
Here is my list of statements to be assessed (they are not necessary my own views - I highlighted the technical questions with bold but if you are interested, feel free to answer any of them):
The kiloton-to-kilogram efficiency of North Korea’s nuclear warheads is likely comparable to US weapons developed in the 1960s and 1970s (0.1-3 kt/kg) - (that was my guess) my friend @geoffodlum suggests that their designs may rather be comparable to US designs in the 1970's or early 1980s
Russian expertise is enhancing North Korea’s nuclear weapons development, including yield and design improvements.
New designs of nuclear weapons require testing to ensure reliability and performance.
North Korea is working on a new nuclear design with a yield higher than 250 kilotons.
Russian support is accelerating North Korea’s progress in nuclear development.
China really (not just officially) wants North Korea to refrain from conducting any further nuclear tests.
North Korea is determined to conduct another nuclear test at some point in the future.
Past warnings about nuclear tests were not necessarily false alarms but reflect a gradual development process.
China would impose significant pressure on North Korea if test preparations were discovered.
North Korea could successfuly use techniques similar to India’s to conceal nuclear test preparations from international observation, including from China and the US.
North Korea’s current geopolitical strategy makes a nuclear test within the next six months advantageous from their perspective
North Korea is working on new nuclear weapon designs.
The probability of a nuclear test increases over time.
North Korea relies heavily on its nuclear program to maintain international relevance.
North Korea is in a stronger position now due to support from Russia and China, reducing the need for saber-rattling.
The absence of visible test site activity, a reliable indicator of no imminent test.
In the short term (at least 6 months) North Korea will focus on missile launches or other provocations rather than nuclear tests.
North Korea’s collaboration with Russia makes a nuclear test less likely in the short term (at least 6 months).
If this request from me would disturb your work in any way, please ignore it.