Would a first strike by NK or the U.S. upon NK result in a world wide Great Depression or Great Recession?

This is quite likely to happen given all present variables. For example, how many cars, cell phones like Samsung Androids, products made in South Korea would immediately stop. It likely would take the world about a month or two to use up all products from there but with Seoul, Korea gone any South Korean product, car or truck would stop along with all parts from these products either permanently or temporarily depending how bad this got for how long?

This kind of interruption likely should be compared to being at least as bad as the 2011 tsunami and Earthquake in Japan where all Nuclear power plants had to be shut down in Japan for some time because of the earthquake and all the aftershocks from a 9.0 earthquake I believe it was then.

And also now we are going to be dealing with 25,000 years to 50,000 years of plutonium from one of the meltdowns there that reprocessing weapons grade plutonium then that will be going into the ocean almost forever from a human point of view.

We likely should expect weapons grade nuclear problems running down rivers above ground and below ground into the ocean from NOrth Korea after this conflict was over for 25,000 to 50,000 years as well radiating the fish in the oceans as it spreads worldwide through the 7 seas on ocean currents as well when and if this conflict happens. This likely would increase cancers worldwide as it moves through the food change because of water. I'm not sure what happens when water evaporates I don't think radiation can evaporate and move through the clouds and come down to earth again. I'm not sure if studies have been made regarding this sort of thing. However, I do know John Wayne died eventually from a radiated particle (one or more) that got into his lungs (as well as many other people that made a movie with him downwind of a Nevada Nuclear Test site. So, all you need is one radiated particle that stays in your lungs over 20 years to die from nuclear radiation.

So, even though 25 to 50 million people could die within the first weeks time likely many more than that would die of radiation and cancer during the following 20 to 30 years after the conflict was over in China, North Korea, South Korea and wherever North Korean missiles landed.