How long would it take for world trade to start recover after a full scale nuclear war? For example, let’s assume USSR and USA got into a war during eighties and of course dragged lots of other countries with them.
I find this interesting because it would have a huge effect for rebuilding efforts. I think I never saw any speculation about this. I am sure there are plans about this in some government safes.
I think what would happen in the short term is that the US and USSR would be absolutely devastated, and presumably so would Europe and other allied nations (Japan, Australia, China). The rest of the world would be struggling to get by with the effects of nuclear winter and the disruption of global trade.
In the medium term, I think we’d see a pretty serious realignment of global power, with southern hemisphere and southerly countries coming to the forefront, especially those with manufacturing and food surpluses. They’d lead the charge in re-establishing global trade I suspect. Meanwhile, the US/USSR/Europe/China would be rebuilding and/or the pieces would be realigning - I kind of doubt the USSR would have existed as a political entity after a nuclear war. It’s entirely possible that the US would be more 19th century-style, in that the states would assume a MUCH larger role in governance, and the Federal government would be relatively feeble.
I suspect that the real answer is “never, or close enough to it.” If we assume a “full scale nuclear war,” as you posit in your post, it’s probably also a safe assumption that a substantial portion of humanity will die immediately, with more dying in the following years due to fallout and climate change.
In such a scenario, how much of humanity would be left, and how much (if anything) would be left of societies, are huge questions, and I think it’s debatable whether humanity (or the planet) would be able to rebound from such a war. Given that, re-establishment of world trade is probably way down the list of things that would happen.
10 years, if you go by the “optimistic assumptions” in On Thermonuclear War 
Classic Dr Strangelove!
Seriously? It’s back to primitive living, stone age style for the survivors.
How many nukes get smuggled to target inside freighters?
If the answer is “one or more”, then no trade for 100 years.
How about thinking about this again? Seriously. 
That might be interesting book to read. 10 years sounds quite a long time though. I would assume many somewhat developed countries survive without being bombed or badly irradiated. They would have an incentive to continue trading as soon as possible. Destroyed countries would be desperate to get food, oil and medicine, which they could trade for gold, machinery, art, weapons, specialists etc.
There might be also trade based on blackmail, as nuclear powers would still have some if their nukes left.
Part of the reasoning goes, sure, you are going to lose New York, Saint Petersburg, etc., maybe 50 to 100 of the largest cities in each country, but a fraction of the population and resources still survive, so you’re not rebuilding from the Stone Age. Similarly, extrapolating to a global scale, not every country will be simultaneously and utterly devastated by ICBMs.
Disclaimer: global thermonuclear war is still not a good idea
That’s what people often don’t realise about this topic. Even in USA countryside and small towns would be left physically pretty much intact.
That is making an assumption that the USSR wouldn’t carpet bomb the entire United States with nuclear weapons; I mean they had enough warheads to do it if they wanted.
Also the electromagnetic pulse generated by the weapons would probably damage areas beyond those directly physically affected by the nuclear explosions.
I admit I could be wrong; there are too many variables involved to make a definitive prediction about what would happen after a full scale nuclear exchange.
Physically intact, perhaps yes, but most places are very dependent on regular shipments of goods from elsewhere in the US and outside the US. That transportation system would be badly broken in the event of global thermonuclear war.
Nope. 2013 figures show the Russians with ~8500 warheads, at least half not deployed. Even with those deployed, you are talking 3.797 million square miles of area in the USA. That’s 1 warhead for every 446.7 square miles. For comparison, the city of Los Angeles is 503 square miles.
There is zero reason to carpet-bomb a target, and multiple targets would get multiple warheads. So there would be large swaths of the US totally untouched by nukes after a war. Whole states, even. It’s not like the Russians are going to waste one on Alaska. Or Wisconsin.
It’s true, most if the trucks would be broken, without fuel, without a driver, robbed or wouldn’t have anything to transport. This has actually been researched a bit: The Consequences of Nuclear War: An Economic and Social Perspective - The Medical Implications of Nuclear War - NCBI Bookshelf
And yes, EMP would probably hit sparsely populated areas as well.
I admit I was wrong about that then.
Do you know if I was wrong about the electromagnetic pulses affecting areas beyond the initial nuclear blasts? Because I was always under the impression that a full scale nuclear exchange would knock out power for the entire lower 48.
Also wouldn’t radioactive fallout get blown over most of the lower 48 as well?
Oh, yeah. EMP would be a bitch. Fallout would be trickier. Depends on prevailing winds, atmospheric patterns and blind luck.
One commodity that would be likely to be traded internationally and quite quickly after the event is food, especially grain, and it will be coming into the north. If North America is reduced to a population in the low dozens then its perhaps not an issue, but any large surviving number will have trouble sustaining itself once the tinned beets run out. With the prime wheat silo land also having been prime missile silo land, its likely that lots of North American agricultural land will be inoperable [perhaps not directly transferable, but watching Chernobyl showed just how bad things will be agriculturally just down-wind].
I’d expect more of the agricultural land in the global South to survive, and capacity for surplus production to remain. The question would be what a war-ravaged USA, Russia or China would have that was of any interest to the survivors in Australia, Kenya or Argentina.
Oh, weeks at least. Thousands of weeks. The first few hundred weeks the survivors will be too busy to try and secure food to make excess goods for the purpose of trade. A few hundred weeks in, some salvage items will likely be traded, but not likely transoceanic. It will be decades before trade returns to levels of the 1600’s.
The question is: how much government, and how much infrastructure, would be left? Would the people and the military left behind still swear allegiance to a government that got us into this mess? Would the road and rail infrastructure survive? Who is going to be shipping valuable food away?
Brazil and Argentina might make out okay, but the global supply chain is quite complex and will be in tatters. Not many new computers for them. But they’ll have food at least.
How long did it take to go from small settlements to today?
About that long.