so, then all the worlds nukes...

[The Jazz Intern]

- suddenly all exploed on the north pole, all at once, at ground level. what happens?

[Nieztchean Uber-Amoeba]

Attention, people of Earth, we have just lost cabin pressure...

[Uraniun235]

It would kick up a tremendous shitstorm of fallout. Where it would land, I have no idea.

I'm not sure how much ice would be melted and how significant that amoutn would be relative to the total icecap.

[Zor]

1-MKShepard Commits Seppuku
2-The People's Republic of China, European Union and Republic of India replace the USA and the Russian Federation as the most powerful military forces on Earth now that the plane has been leveled.
3-North Korea begins to accelerate it's nuclear weapons development project.
4-The heat from all the nukes has a definate effect on the global climate, possibly leading to rising sea levels.

Zor

[Darth Garden Gnome]

Times Square becomes a lovely place to fish...

[Ma Deuce]

The People's Republic of China, European Union and Republic of India replace the USA and the Russian Federation as the most powerful military forces on Earth now that the plane has been leveled.

I don't think so: The US for example still has that enormous navy, which could easily crush the navies of all those other powers combined.

[K. A. Pital]

All the world's nukes? Now? Pfft. A few countries experience a return to medieval, other than that, not much. A 10-gigaton explosion, sure, lots of fallout, sure. Dump 10 gigaton ground burst into "nuclear explosion calculator" and see fallout radius and intensity, to get a clue on what countries are most fucked.

[Zor]

All the world's nukes? Now? Pfft. A few countries experience a return to medieval, other than that, not much. A 10-gigaton explosion, sure, lots of fallout, sure. Dump 10 gigaton ground burst into "nuclear explosion calculator" and see fallout radius and intensity, to get a clue on what countries are most fucked.

They go off at the north pole, several thousand kilometers from any human habitation of sugnifigance.

Zor

[Grandtheftcow]

Would a bunch of nukes going off in close proximity really change much other than the amount of fallout?

[Sikon]

Checking a recent other thread, the world's nuclear arsenal peaked at around 25000 megatons, but it is now about 10000 megatons. So if all devices could be detonated with sufficient precision at the same time, in about the same location, the result is a 10-gigaton explosion.

If the formulas here are approximately valid even with extrapolation into the gigaton range, then thermal radiation would cause 3rd-degree burns out to about a 510-km radius (terrible, lethal for exposure over enough of the body). However, such extrapolation of the complicated scaling for lesser-yield nuclear detonations is uncertain. But earth's curvature provides an upper limit. That limit would depend on the effective size and height of the radiating fireball. Using the calculator here suggests the fireball radius for 10-gigatons would be around 30 km, though vertical radius may not be the same as horizontal radius in this case. So earth's curvature would probably mostly stop the thermal radiation before 500-km, and all direct thermal radiation should be stopped in much under 1000-km of distance.

Other effects might be 4.6-psi overpressure out to on the order of 160-km radius (collapsing most structures) and initial prompt radiation of 500 rems out to around 18-km radius (a bit more than 50% mortality by itself if not for other lethal effects).

Let's use the asteroid impact crater calculator here for a rough estimate by analogy of the 10-gigaton nuclear explosion to a 10-gigaton asteroid impact. Land detonation would make an apparent crater diameter of around 6 km with an apparent depth of around 1.4 km, excavating billions of cubic meters and many billions of tons. An airburst at some altitude over ground would create a much more shallow but far greater diameter crater. But actually there is not land at the north pole, and this is to be a detonation at sea level in the ocean or ice.

If the 10-gigatons of nukes were detonated at sea level, effects would include production of giant waves. Some publications suggested an asteroid impact of a few gigatons yield would produce tsunami waves decreasing in intensity only very slowly with distance, being devastating out to great distance. However, an article here suggests more recent modeling of an asteroid impact in the general region of 15 gigatons implies wave height dropping to under a meter by around 1600 kilometers. It could be amplified at some shores, but see the map later for the lack of landmass around the North Pole. Treating 10-gigatons of nukes as equivalent to a similar gigatonnage asteroid impact may be imperfect, but it gives some idea, suggesting the waves produced would be no worse than the preceding.

Assuming a similar ratio of fission to fusion yield, the amount of radioisotopes in fallout from the 10-gigatons of nukes detonating would be about 23 times greater than 440-megatons of past nuclear tests. Such would differ, though, due to being detonated in a different location, with exact dispersion depending on many factors. But roughly approximating as comparable to 23 times past nuclear testing would result in an estimate of around 160 million man-Sv of exposure from the fallout radioisotopes, for the total up through the subsequent couple centuries.

Average natural radiation exposure is around 2.4 mSv per person annually for 6.5 billion people or around 16 million man-Sv a year, so the preceding might be on average equivalent to around a decade of natural radiation exposure. References involved in the preceding are here and here. Of course, some people would receive more, and some less, some dying if in areas where fallout was relatively concentrated. Localized fallout levels would initially be lethal, probably over thousands of square kilometers, although that area would be limited compared to the world's total surface area of 510 million square kilometers.

For general perspective, compare all of the preceding to a map here. Observe the limited landmass within a radius of 1000-km or even 2000-km from the North Pole. Remember a radius of 1000 km involves 3.14 million square kilometers.

In summary, considering all of the preceding, the devastation from the 10-gigaton North Pole detonation would tend not to reach Canada or Russia outside of their northern islands, aside from more limited indirect effects. The worst effect would be on any few people unfortunate enough to be within a few hundred kilometers or so of the North Pole at the time of detonation...

[K. A. Pital]

Detonating 10 gigatons shouldn't be raising a serious tsunami threat - as far as I understand, a 100-gigaton earthquake caused the indonesian 2004 tsunami. This is 10 times less, and the shores against which this possible tsunami would strike are sparsely populated.

[Siege]

Well, we lose the polar bears, that's for sure.

Incidentally, how long would it take for some degree of nuclear re-armament to occur? Can all these nukes be easily replaced?

[Mr Bean]

Incidentally, how long would it take for some degree of nuclear re-armament to occur? Can all these nukes be easily replaced?

America yes, we still have the old materials sitting under plastic in storage. We might conceivably have full nukes being produced inside of a month if we wished it. However we will slam into a wall of "not enough weapons grade material" after we run through our current stocks. I don't know about Russia but considering the previous communist attitudes towards nukes they most like as just as well prepare as we are for reproduction, having squirreled away the materials if not perhaps the trained personnel.

Great Britan, France and China? Anyone's guess.

And FYI there's a huge difference between having ready to go nuclear bombs, and having ready to fly ICBM's.

[Sikon]

Detonating 10 gigatons shouldn't be raising a serious tsunami threat - as far as I understand, a 100-gigaton earthquake caused the indonesian 2004 tsunami. This is 10 times less, and the shores against which this possible tsunami would strike are sparsely populated.

Well, my main point is that the tsunami would tend not to be too serious given the drop in wave intensity over distance, combined with the distance of its starting location from landmasses. The figures I mention are directly from the article linked aside from unit conversion, albeit with the analogy of treating the nuclear explosion like an equivalent gigatonnage asteroid impact. That isn't a perfect analogy, since a large high-momentum impacting mass isn't exactly the same as the nuclear explosion, despite having some similarities when velocity is high enough for a mainly omnidirectional blast at impact. But it seems plausibly a better analogy than an equivalent gigatonnage earthquake. At least a 10 gigaton nuclear detonation would explosively form a large cavity in water that would subsequently collapse, perhaps a little like the asteroid impacts discussed in a paper modeling them here, if one adjusts for yield, noting that the paper suggests a 1/4th power scaling with energy.

The energy of an earthquake would be delivered over a different time scale, over a different area, and in a different, complicated manner. Besides, I wouldn't even be sure that the 2004 Indian Ocean earthquake really was 100 gigatons, despite multiple web pages stating that. For example, a document here says the energy release was estimated as 4.3E18 joules and goes on to say that is equivalent to 100 gigatons of TNT. But I know from many sources including the definition of the term and here that 4.2E12 joules is a kiloton. So 4.3E18 joules would be about 1000,000 kilotons, which is 1000 megatons or 1 gigaton, not 100 gigatons. A web page states it has been estimated as 3.35E18 joules, 0.8 gigatons, but a later more refined estimate was 1.1E18 joules, which would be around 0.25 gigatons.

What definitely limits the effect of the nuclear detonation is that the shores against which the waves would strike are sparsely populated, as you suggested, and the North Pole is so distant from the body of countries like Canada and Russia.